A Cyclopædia of Practical Receipts, Processes, and Collateral Information (part 9)

Chloral, Hydrate. C2HCl3O. Aq. Syn. Hydrate of chloral. Prep. “Pass dry chlorine gas, for several days, through absolute alcohol, sp. gr. 0·795, until it becomes a thick viscid liquid of sp. gr. 1·57. At the beginning of the operation the alcohol is well cooled to prevent inflammation and explosion, but towards the end of the operation the alcohol is heated nearly to the boiling point. The resulting liquid, which after a day or two solidifies to a mass of crude chloral hydrate, is agitated with four times its bulk of concentrated sulphuric acid, and the anhydrous chloral which floats on the surface is separated and purified by fractional distillation. The purified anhydrous chloral is placed in a still, mixed with 11 per cent. of water, and distilled over chalk to remove any hydrochloric acid that may be present; the resulting solid distillate is then fused and poured out into shallow vessels to cast into cakes.” (Squire.) The purest chloral hydrate is said to be that which has been crystallised two or three times out of pure bisulphide of carbon.—Prop. White opaque solid, having a pungent odour resembling that of a ripe melon. Soluble in water, glycerin, and alcohol. Gradually volatilises in the air, and may be distilled without decomposition. From 100 gr. dissolved in ⁄2 fl. oz. of water, well shaken with 1 fl. oz. of solution of potash (B. P.), and allowed to stand for several hours, at least 46 grain-measures of chloroform should separate.

Chloral hydrate may be obtained in crystals by mixing the cake with about half its bulk of chloroform, and putting aside in a cool place. When the crystallisation is complete (which is generally in about 8 or 10 days) the crystals are freed from the mother liquor by a centrifugal machine, and afterwards dried at a gentle heat. The mother liquor may be utilised for future crystallisations.

Uses. An excellent sedative, antispasmodic, hypnotic, anodyne. It has done good service in hypochondriacal and other nervous affections, as well as in the insomnia of the insane, and of dipsomaniacs; also in asthma, hooping-cough, and scarlet fever. It has also the reputation of being an efficient preventive of sea-sickness, especially on short voyages, such as crossing the channel, which can be accomplished during the sleep occasioned by the agent.—Dose, from 10 to 60 gr.

It was introduced into medical practice by Dr Liebreich, of Berlin. Immense quantities are imported into this country from Germany.

CHLORALUM. An impure aqueous solution of chloride of aluminum, sp. gr. 1·15, 1 fl. oz. of the liquid contains 75 grains of anhydrous chloride. Introduced by Professor Gamgee as an antiseptic and disinfectant, for which purposes it is recommended to dilute the article as sold with four times its bulk of water.

CHLO′′RATE. Syn. Hyperoxymu′′riate†, Chlo′′ras, L. A compound in which the hydrogen of chloric acid, HClO3, is replaced by a metal or other basic radical, e.g. KClO3, chlorate of potassium. Chlorates may be prepared by dissolving the hydrate or oxide in chloric acid, and crystallising. The alkaline chlorates, however, are made by passing chlorine into solutions of the hydrate or carbonate of potassium or sodium, boiling the resulting liquid, and separating the chlorate from the chloride, which is also formed by crystallisation. They are very similar to the nitrates, both in their general properties and composition. They are all decomposed at a red heat, metallic chlorides being formed and oxygen gas given off. Like the nitrates, they deflagrate with inflammable substances, but with greater facility and violence. A mixture of this kind will detonate with a slight blow or friction. All the chlorates are soluble in water.

Char., Tests, &c. The chlorates are known by their deflagrating when placed on red-hot charcoal. By evolving a yellow gas when treated with concentrated sulphuric acid, in the cold, which gas also communicates to the liquid a red or yellow tinge. By evolving oxygen gas when heated alone in a test-tube. This test is not characteristic, unless carried a stage further, by dissolving the residual chloride out of the tube, and adding to the filtered solution a few drops of nitrate of silver; then the formation of a white precipitate, insoluble in nitric acid, will show that the salt treated was a chlorate, and not a nitrate. Pure chlorates give no precipitate with nitrate of silver.

CHLORHY′DRIC ACID. See Hydrochloric Acid.

CHLO′′RIC ACID. HClO3. Syn. Hyperoxymuriat′ic acid; Acidum chlo′′ricum, L. An acid discovered by Chenevix, but first obtained in a separate form by Gay-Lussac.

CHLO′′RIDE (-ĭd). Syn. Chlo′′ruret†; Chlori′dum, L. A chemical compound of chlorine with a metal or other basic radical, e.g. NaCl, chloride of sodium; C2H5Cl, chloride of ethyl.

Prep. The majority of the metallic chlorides may be made by simply dissolving the metal or its carbonate, oxide, or hydrate, in hydrochloric acid (previously diluted with about twice its weight of water), and evaporating and crystallising the solution in the usual manner. Zinc, cadmium, iron, nickel, cobalt, and tin, dissolve readily in hydrochloric acid; copper only in strong boiling acid; silver, mercury, and gold, not at all. The insoluble chlorides, as those of silver and mercury, may be readily prepared by precipitating any of their corresponding soluble salts with hydrochloric acid, or a soluble chloride, such as common salt. Anhydrous chlorides are generally prepared by the direct action of chlorine on the bases.

Char., Tests, &c. Most of the metallic chlorides are soluble in water. Many fuse when heated, and volatilise unchanged, but others are completely or partially decomposed at a red heat. All, with the exception of those of the alkali and earth metals, are decomposed at a red heat in a current of hydrogen. They are recognised by the following reactions:—1. Heated with a little peroxide of manganese and sulphuric acid, chlorine is evolved, and easily detected by its colour, smell, and bleaching properties:—2. The soluble chlorides may be readily detected by their solutions, slightly acidulated with nitric acid, giving with a solution of nitrate of silver a white, curdy precipitate (chloride of silver), insoluble in nitric acid, freely soluble in liquor of ammonia, and blackened by the light:—3. The insoluble chlorides may be tested by digesting them in a little liquor of potassa, when a solution of chloride of potassium will be formed, which may be treated as just directed (2); or the chloride may be dissolved in nitric acid, and tested with nitrate of silver as before.

CHLORIM′ETRY. See Chlorometry.

CHLORINA′TED LIME. See Lime.

CHLORINA′TED SO′DA. See Sodium.

CHLO′′RINE. Syn. Chlorin′ium, L.; Chlore, Fr.; Chlor, Ger. An elementary substance discovered by Scheele in 1774, and at first supposed to be a compound body. In 1809 MM. Gay-Lussac and Thénard suggested the probability of it being a simple substance; but it was reserved for Sir H. Davy, shortly afterwards, to demonstrate the truth of the suggestion of these foreign chemists.

Nat. Hist. It exists in nature chiefly in the form of chloride of sodium, which constitutes rock salt when deposited in inland beds, sea salt when dissolved in masses of water. The sea also contains chlorides of potassium, calcium, and magnesium. It is a constituent of several well-known minerals. It has been met with in the air of volcanic districts, combined with hydrogen, as hydrochloric acid.

Prep. Strong hydrochloric acid is poured on half of its weight of finely-powdered peroxide of manganese, previously placed in a glass flask or retort; chlorine gas is immediately evolved, even in the cold, but much more rapidly on the application of a gentle heat, and is collected in clean, dry bottles by displacement. The tube conducting the gas is so arranged as to reach to the bottom of the bottle, and the chlorine, being heavier than the air, displaces the latter without mixing with it. The bottle is known to be full by the gas, easily perceived by its green colour, overflowing the top of the vessel. The bottle is then closed up with an accurately fitting stopper, previously greased, and an empty one put in its place, which is subsequently treated in like manner. To free the gas entirely from hydrochloric acid it is passed through a wash bottle containing a small quantity of water; and to render it quite dry it is passed over fused chloride of calcium. When the presence of moisture is no object chlorine may be collected over warm water, or, what is better, a saturated solution of common salt, in the pneumatic trough. The mercurial trough cannot be employed, as the chlorine rapidly acts upon the metal, and becomes absorbed.

Commercial.—From oil of vitriol and water, of each 7 parts, cautiously mixed, and allowed to cool; chloride of sodium (common salt), 4 parts, mixed intimately with peroxide of manganese, 3 parts. The dilute acid is placed in a retort or other generating vessel, and the powder added. The gas comes off slowly at first, but the application of a gentle heat causes it to rush forth in large quantities. Of late years, owing to the general demand for bleaching agents, numerous new methods and suggestions for obtaining chlorine have been patented, of which the following are the most important.

1. Elliott. By this method the reconversion of the chloride of manganese to peroxide was attempted as follows:—The manganese residues left in the still are first heated to dryness. They are then roasted in a current of steam, the result being the formation of hydrochloric acid (which is condensed), and a residue consisting of a mixture of protoxide and peroxide of manganese.

2. Gatty. In this process the manganese residues, after evaporation to a suitable consistence, are mixed with nitrate of soda, and the nitrate of manganese and chloride of sodium formed, when dried, are strongly heated in an iron retort, the fumes of nitric acid which come off being employed in the manufacture of sulphuric acid. The residue in the retort, consisting of peroxide of manganese, being lixiviated, yields the peroxide in a pure state:

Mn(NO3)2 + 2(NaCl) + O2 =

MnO2 + 2NaCl + 2(NO3).

3. Hoffman. This process consisted in the regeneration of the manganese by means of soda waste. In this process the chloride of manganese is, by the addition of the yellow ley obtained from the lixiviation of soda waste, converted into sulphide of manganese. The precipitate so obtained consists of

Sulphide of manganese 55·00

Sulphur 40·00

Protoxide of manganese 5

100·00

This is dried and then calcined, the sulphurous acid evolved being conducted into the sulphuric acid chamber.

The residue, which has the following composition—

Sulphate of manganese 44·50

Peroxide of manganese 18·90

Protoxide of manganese 36·60

100·00

—is next mixed with nitrate of soda and heated to 300° C., yielding sulphate of soda and nitrate of manganese, the latter, however, being at once decomposed into peroxide of manganese, and nitrogen peroxide, thus:—

a. MnSO4 + 2NaNO3 = Mn(NO3)2 + Na2SO4.

b. Mn(NO3)2 = MnO2 + 2NO2.

After the mass has cooled, the sulphate of soda is washed out, the residue yielding, according to the inventor, a material equal to native peroxide of manganese.

4. Schlösing. Manganese is acted upon with a mixture of hydrochloric and nitric acids, the degree of concentration of the acids being so regulated by the addition of water that the mixture yields only chlorine, whilst protonitrate of manganese is formed; this salt being calcined yields peroxide of manganese and nitric acid. The nitric acid aids the oxygen of the air in decomposing the hydrochloric acid.

The following equation will explain the successive stages of the reaction:—

a. 2HCl + 2HNO3 + MnO2 = Cl2 + Mn(NO3) + 2H2O.

b. Mn(NO3)2 = MnO2 + 2NO2.

c. 2NO2 + H2O + O = 2HNO3.

5. Vogel. By decomposing chloride of copper by heat. The chloride in the crystalline state is mixed with half its weight of sand and heated in earthenware retorts to 200° to 300° C., yielding chlorine gas, while the remaining protochloride of copper is reconverted into perchloride by the action of hydrochloric acid.

According to Laurens the reaction is as follows:—

a. 2CuCl2 = Cl2 + 2Cu22Cl2.

b. Cu2Cl2 + 2HCl + O = H2O + 2CuCl2.

6. MacDougal, Rawson, and Shanks. This is effected by decomposing chromate of lime by means of hydrochloric acid, the result being the formation of chloride of chromium, chloride of calcium, and the evolution of free chlorine; thus

2CaCrO4 + 16 HCl = Cr2Cl6 + 2CaCl2 + 8H2O + Cl6

158 parts of chromic acid yield 106 parts of chlorine. The chloride of chromium is again precipitated with carbonate of lime, and by ignition converted into chromate of lime. Only three eighths of the chlorine contained in the hydrochloric acid is given up, whilst manganese yields one half.

7. Hargreaves proposes to evaporate a solution of protochloride of iron to dryness, and then to heat the dried substance in a current of air, at a temperature of about the melting point of zinc, by which means perchloride of iron and free chlorine would be obtained. Thielbierge’s suggestion consists in passing air over protochloride of iron, and so giving rise to peroxide of iron and chlorine. This, like Hargreaves’ proposition, possesses the disadvantage of furnishing the chlorine very largely diluted with air and nitrogen.

8. Jessie de Mothney. This chemist has proposed a continuous process which is as follows:—Peroxide of manganese either alone or mixed with lime is put into a retort, which, when heated to redness, has a current of hydrochloric acid gas passed into it. A disengagement of chlorine and steam takes place, and there remains in the retort a mixture of undecomposed peroxide of manganese with chlorides of manganese and calcium. The retort containing the undecomposed peroxide and chlorides being still kept at a red-heat, air or oxygen is passed over them, the result being that the manganic chloride is decomposed at once.

The chlorine liberated by this last operation is conveyed into vats containing a mixture of lime and manganous oxide, which substances have been previously formed by the decomposition of the manganous chloride by lime, the soluble chloride of calcium having been run off. Sesquioxide of manganese and hypochlorite of calcium are formed in the vats, and these two, reacting on each other, give rise to peroxide of manganese and chloride of calcium. With fresh hydrochloric acid this latter product yields more chlorine for use in the chambers. Magnesia may be substituted for lime.

9. Dunlop. This process, which may be regarded as the first practical method for utilising the whole of the exhausted manganese residues, and rendering them capable of reapplication in the production of chlorine, was devised by Mr Dunlop in 1855, since which time it has been in use in the alkali works of the Messrs Tennant, at St. Rollox, Glasgow. The operation consists in precipitating the chloride of manganese in the still liquor by carbonate of calcium; the resulting manganese carbonate being decomposed by heat. The liquors are previously mixed with a little milk of lime, which frees them from ferric oxide, alumina, and silica.

Being allowed to stand until these and all other insoluble matters are precipitated, the clear solution containing the chloride of manganese is mixed with finely divided chalk, when the following reaction ensues:—

MnCl2 + CaCO3 = MnCO3 + CaCl2.

The resulting milky liquid is then run into large iron boilers, through each of which passes horizontally an iron shaft furnished with a number of projecting arms. This shaft having been put into revolution so as to keep the contents of the boilers agitated, steam is admitted into them under a pressure of from two to four atmospheres, and by the combined effects of heat and pressure the decomposition of the manganese chloride by the calcium carbonate is accomplished in about four hours. The manganese carbonate is then allowed to subside, the calcium chloride solution is drawn off, the precipitate carefully washed, and thrown up in heaps on an inclined surface to drain. When partially dried the carbonate of manganese is placed in small low wagons, made of sheet-iron, supported on rollers, and slowly drawn through a furnace by means of a chain. The furnace holds forty-eight of these little wagons. The furnace is 50 feet long, 12 feet wide, and 10 feet high. “A fire-brick flue runs down the centre of the bottom of the furnace, and is connected at the far end with two return metal pipes, which lie on each side of the flue. A uniform heat at about 660° F. is maintained in the furnace, in which four lines of rails are laid for the small wagons to run along. The half-dried substance loses all its moisture and part of its carbonic acid as the wagons pass along the first line of rails, and as they return down the second line a further escape of carbonic acid ensues, and eventually the expulsion of all the acid, and the peroxidation of the manganese is completed during the passage of the wagons on the third and fourth lines.” The operation lasts about forty-eight hours, the substance gradually changing in colour from white to brown, and lastly to black.

The ends of the furnace are closed by loose hanging doors, so as to ensure the entrance of a sufficient supply of air. The fire-place is situated below the floor of the furnace, and requires very careful watching. The resulting product is a mixture of oxides of manganese, and contains about 72 per cent. of peroxide of manganese.

9a. A. Dunlop. Another process designed by Mr Dunlop, and also in use at Messrs Tennant’s, is as follows:—Nitrate of sodium (Chilian nitre) and chloride of sodium are decomposed by being heated in cast-iron cylinders with sulphuric acid. The gaseous products are made to pass through leaden Woulff’s bottles containing sulphuric acid, which absorbs the nitric peroxide formed, and allows the passage of the chlorine into the chambers. The reaction may be represented by the following equation:—

NaCl + NaNO3 + H2SO4 = Cl + NO2 + Na2SO4 + H2O.

The sulphuric acid charged with nitric peroxide is used in the manufacture of chamber acid.

10. Weldon. a. The process by which the greater part of the chlorine employed in the manufacture of bleaching compounds is now obtained and which has hitherto proved the most practical is that of Mr Walter Weldon. We have the authority of Mr Kingzett, in his work on ‘The Alkali Trade,’ for the statement, that out of 90,000 tons of bleaching powder made in Great Britain in 1874, 50,000 were procured by Weldon’s method; and turning to the Continent we find the process largely adopted in Germany, France, and Belgium. The utilisation and regeneration of the residual product left in the still after the evolution of the chlorine which it will be presently seen is accomplished by the above process, is not the only advantage accruing from it, since it has also been the means of removing an extensive source of contamination of many of our streams and rivers, into which the then useless chloride of manganese was thrown previous to Mr Weldon’s invention. It is true that the only waste product formed in the course of the operations, viz., chloride of calcium, is got rid of by being run into the nearest waters, but it is stated by the Rivers Pollution Commission, beyond making these harder, no other objectionable effect is caused by it.

Mr Weldon’s process is based upon the fact, that if protoxide of manganese be suspended in a solution of chloride of calcium, and an excess of lime be added, the protoxide will become readily converted into peroxide if air be forced into the liquor. It had long been known that it was possible to convert into a peroxide the protoxide of manganese obtained by treating the residual still liquors with an equivalent of lime, but all attempts to reduce this knowledge to practical account had proved unsuccessful until Mr Weldon attempted it.

Mr Weldon made the important discovery, that whilst protoxide of manganese is by itself, when treated in the wet way with air, only capable of being converted into peroxide, at the greatest, to the extent of one half; the addition to the protoxide so treated of a certain quantity of lime converted the whole of it into peroxide in less than a twentieth the time required to peroxidise half the protoxide if lime were absent. It will be seen that it is the employment of an excess of lime which constitutes the success of Mr Weldon’s process, which is as follows:—

The residual liquors remaining in the still after the chlorine has been evolved by the action of hydrochloric acid on peroxide of manganese, and in which chloride of manganese is by far the predominating constituent, are run into a receptacle termed the neutralising well, which is usually six feet in depth by twenty in diameter. In this well the free hydrochloric acid of the still-liquor is neutralised by the addition of limestone or chalk, which at the same time serves to decompose the soluble ferric and aluminic chlorides present in the liquid, and to precipitate them as insoluble oxides. During this process the contents of the well are kept in a state of brisk agitation by means of a suitable stirrer. After this treatment the now neutral liquor consists of chlorides of manganese and calcium in solution, of a small quantity of suspended ferric and aluminic oxides and chalk. It additionally contains also in suspension a by no means small quantity of sulphate of lime, derived from the sulphuric acid always present in varying amount in the commercial hydrochloric acid used.

From the neutralising well the liquor is pumped to a height of some forty feet into tanks, called the chloride of manganese settlers, in which after from two to four hours it deposits the solid matters suspended in it, the supernatant clear liquor assuming a pale rose-coloured appearance.

The next operation is to draw off by means of syphons, which can be lowered or raised in the settlers to any desired level, this clear liquid, containing the chlorides of manganese and calcium, into a vessel called the oxidizer; this latter being an iron cylinder, of from eight to twelve feet in diameter, and from twenty-two to thirty-five feet deep. Two pipes go down nearly to the bottom of the oxidizer; the larger one being used for conveying a blast of air from a blowing engine, and the smaller for the injection of steam. The introduction of steam is only had recourse to in case the liquor when drawn into the oxidizer should not have the requisite temperature, viz. 130° or 140° Fahr. Immediately above the oxidizer a reservoir containing milk of lime is placed. A great deal depends upon the careful preparation of the milk of lime, since on the degree of fineness in which the lime is added to the manganese chloride in solution depends the rapidity with which it acts in the oxidizer. The milk of lime is kept constantly agitated, to ensure its being of uniform consistency, and should contain from 15 lbs. to 20 lbs. of hydrate of lime in every cubic foot of the mixture.

A charge of the clear liquor having been drawn into the oxidizer, and raised if necessary to the requisite temperature, the blowing in of air is begun, whilst at the same time the milk of lime is run into the oxidizer as rapidly as possible, the flow of milk of lime being only discontinued when a sample of the filtrate drawn off, by means of a tap placed near the bottom of the oxidizer, ceases to give the manganese reaction when mixed with a solution of bleaching powder. This reaction consists in the production of a purple colour caused by the formation of permanganate of calcium. More milk of lime is then added, when the contents of the oxidizer are found to consist of a thin white mud, composed of a solution of calcium chloride, holding in suspension a mixture of protoxide of manganese and lime. The injection of air being continued the white mud rapidly becomes darker in colour, and soon changes into a thin black mud composed of solution of calcium chloride, holding in suspension certain compounds of peroxide of manganese partly combined with protoxide of manganese, but chiefly with lime, which compounds Mr Weldon terms “manganites.” Mr Weldon suggests that the manganites so formed may be regarded as salts in which the basic radical is calcium or manganese, and the acid radical MnO3; and may be represented by the formulæ CaMnO3, and MnMnO3; and possibly also CaMnO2 (MnO2)2. “The quantity of lime which has to be put into the oxidizer before the filtrate from a sample of its contents ceases to yield the manganese reaction varies very considerably. Recently precipitated protoxide of manganese dissolves very appreciably in neutral solution of chloride of calcium, its solution therein comporting itself with reagents exactly like solutions of manganese salts. It dissolves also in solution of oxychloride of calcium, that is to say, in solution of chloride of calcium containing dissolved lime; its solution in oxychloride of calcium not giving the ordinary manganese reactions.”

“Hence even if all portions of the lime added to the chloride of manganese in the oxidizer were capable of acting on chloride of manganese equally readily, manganese could not cease to be so in solution as to be detectible by ordinary reagents, until more than an equivalent of lime had been added—that is to say, until enough had been added not only to decompose all the chloride of manganese, but also to form a certain quantity of oxychlorate of calcium. It is never the case, however, that all portions of the lime used are capable of acting on the chloride of manganese with equal readiness. The lime used always contains a larger or smaller proportion of particles coarser than the rest, which coarser portions cannot of course act so rapidly as the finer ones; and as the decomposition of the chloride of manganese requires to be completed as quickly as possible, those portions of the lime which will not act upon it instantly are scarcely allowed time to act upon it at all.

“These coarser portions of the lime thus contribute very little to the decomposition of the manganese, though they afterwards dissolve completely in the hot solution of chloride of calcium, and then play their full part in the reactions which take place during the subsequent blowing. The proportion of lime which thus does not act on the chloride of manganese varies with the source of the lime, and with the manner in which it is prepared, so that the quantity of lime which has to be added to a charge of chloride of manganese liquor in the oxidizer, before the filtrate from a sample of the resulting mixture ceases to become coloured on the addition of solution of bleaching powder, varies from about 1·1 to 1·45 equivalent.

“The further quantity of lime which is added after that point has been reached is now usually so much as to raise the total quantity to about 1·5 to 1·6 equivalents, being from one half to six tenths in excess of the quantity which actually takes part in the decomposition of the chloride of manganese.”

As previously stated, Mr Weldon found that if only so much lime is employed as is necessary to precipitate the manganese, not more than half the protoxide of manganese will be converted into the peroxide, and that even this result will be accomplished very tardily. And, as has been already mentioned, a greater and more rapid yield of protoxide can only be obtained by using a larger proportion of lime. Any excess, however, of lime over that absolutely required for the peroxidation of the protoxide of manganese must be sedulously avoided, since a superabundance of lime leads to the formation of compounds that are not readily peroxidised. Should such compounds be formed, it is necessary to destroy them, and this may be done by the addition of a fresh quantity of chloride of manganese. The objectionable compounds in question are lime and protoxide of manganese, which are known in the process under the name of “bases;” and the reason why it is desirable to prevent as much as possible their formation will become evident when it is remembered that they cannot furnish chlorine when treated with hydrochloric acid, but that they merely dissolve in this latter.

The injection of air into the oxidizer, which constitutes the blowing operation, varies from two to four hours.

The quantity required to be blown in is chiefly dependent upon the depth of the oxidizer, and upon the amount of protoxide of manganese contained in a given volume of the charge.

The greater the depth of this latter the more rapidly does the peroxidation take place; and the greater the number of molecules of protoxide in a given volume of the charge, the larger is the total surface presented to the action of injected air, and consequently the greater is the proportion of the oxygen absorbed.

“In one instance 175,000 cubic feet of air were blown in during five hours, and of the oxygen contained in this, 14·8 per cent. (equal to rather more than 4 cwt.) was absorbed in the production of 22 cwt. of peroxide of manganese.”

The expenditure of mechanical power in forcing the air into the oxidizer averages between seven and eight horse-power for every 100 lbs. of peroxide of manganese obtained. In theory, to produce the quantity of chlorine contained in a ton of bleaching powder containing 37 per cent. of chlorine, 1020 lbs. of peroxide of manganese would be required; but it is found in practice that instead of this quantity of peroxide giving the above result, 1100 lbs. are needed.

“The consumption of lime averages 14 cwt. per ton of bleach. By this process 1 ton of bleach is made, using 2832 lbs. of hydrochloric acid, generated by the decomposition of 47·5 cwt. of salt, viz. a quantity which theoretically yields 3334 lbs. of hydrochloric acid. There is therefore a loss of acid of 15 per cent. The loss of manganese varies from 4 to 10 per cent. The whole of the lime is lost, and two thirds of the total chlorine (in combination with calcium) contained in the acid used.

When sufficient air has been blown into the oxidizer, the contents which consist of a solution of chloride of calcium, holding in suspension peroxide and protoxide of manganese and lime, are run into one of a range of settling tanks placed below the level of the oxidizer. These tanks are known as mud settlers. In these the manganese mud is left to deposit until about half its volume has become clear. It generally requires 3 or 4 hours to deposit. The clear part, which consists of chloride of calcium, being then decanted by means of a swivel-pipe, is usually thrown away. The mud remaining in the settlers, which contains in a cubic foot from 4 lbs. to 5 lbs. of peroxide of manganese, is now in a fit condition to be placed in the still, where it is to be exposed to the action of the hydrochloric acid. The stills, which are made of slabs of hard siliceous sandstone or of Yorkshire flagstones, and are usually in the shape of an octagonal prism, are about 8 feet square, and 10 feet in depth. Mr Kingzett says “the new Weldon stills are polygonal in shape, about 12 feet across, and 7 feet to 8 feet deep.” Contrary to the course formerly followed, when native manganese was used in the Weldon process, the still is charged with hydrochloric acid first, and the manganese mud is run in upon the acid in a small, steady stream, the flow of which can be regulated by a stopcock. Steam being carefully admitted into the still at the same time, the mud dissolves very rapidly in the acid, and the chlorine is evolved in an even current, the force and flow of which is dependent upon and can be very accurately regulated by the admission of the mud.

The time occupied before the reaction between the acid and the manganese is completed varies in different works from two to six hours. At the end of this time the contents of the still are run off into the well placed below it, and are afterwards submitted to the various operations already described, which we have seen to accomplish the regeneration of the residue and effect its reconversion into peroxide of manganese. The process is a continuous one, and theoretically the original quantity of manganese should be capable of being used over and over again for an unlimited number of operations. In practice, however, there is always found to be a loss of a small per-centage of manganese, arising from some of the chloride of manganese being carried down by the sulphate of lime and the ferric and aluminic oxides in the settlers, and not being thoroughly recovered when the deposit is washed; for, though an exhaustive washing of the precipitated matters could be easily managed, the bulk of the wash waters would render the recovery of the chloride of manganese from them a non-paying affair. This loss of chloride varies according to the statements of different manufacturers from 2 to 10 per cent.

It is stated that not only is the chlorine yielded by Mr Weldon’s process of very pure quality, and the bleaching powder manufactured from it very high of strength and excellence; but that over from 20 to 25 per cent. more bleach is obtained from a given quantity of hydrochloric acid, when artificial peroxide of manganese is used instead of the native. This advantage is chiefly owing to the artificial manganese (of the manganese mud) from its physical condition being much more accessible than the native form of manganese to the action of the hydrochloric acid, and from its dissolving in the acid so much more readily and thoroughly, and neutralising as much as from 95 to 99 per cent. of it, a much larger amount than the native ores are capable of neutralising.

Again, the bleaching powder produced by the above process stands not only very high in point of strength, but varies very little in the amount of chlorine it contains, as may be gathered from the following table, which shows the average strength for thirteen consecutive weeks of the bleaching powder made at six large and different manufactories:—

Factory.

Week. I. II. III. IV. V. VI.

1st 36·9 37·8 36·7 36·3 36·6 36·6

2nd 36·1 36·8 36·7 36·2 35·1 37·4

3rd 36·5 38·0 36·6 36·1 37·2 37·9

4th 35·9 37·1 35·9 36·2 36·8 37·1

5th 35·8 36·9 36·0 36·3 36·5 37·8

6th 36·0 37·0 36·2 35·9 36·5 37·2

7th 36·5 36·0 36·3 36·6 35·8 36·8

8th 36·3 36·8 36·3 36·3 35·0 37·1

9th 36·4 36·3 36·8 35·7 35·2 37·0

10th 36·5 36·7 36·3 36·0 36·2 37·6

11th 36·8 36·8 36·2 35·9 36·0 37·2

12th 36·8 35·9 35·6 35·6 36·1 37·2

13th 36·7 35·2 35·9 36·1 36·9 37·5

Spite of the expensive plant required to work Mr Weldon’s process, it is said to possess very decided advantages over the old methods as far as regards cost of production.

In connection with Mr Weldon’s process may be mentioned Mr Valentin’s modification of it, for which a provisional patent was taken out by this latter gentleman. Instead of adding more lime, after the neutralised still liquors have been precipitated by an equivalent of lime, as is done in the above process, Mr Valentin adds a solution of potassium ferricyanide, and air being blown in, the peroxidation of the manganese is effected much more quickly than in Mr Weldon’s process. It was also calculated that, by Mr Valentin’s method, bleaching powder could be produced at a cost of about ten shillings per ton less than when made by Mr Weldon’s.

For the successful working of Mr Valentin’s process it is necessary that the ferricyanide should be recovered, not only because of its cost, but also because its presence gives rise to the production of cyanogen compounds, which would enter the chamber with the chlorine. Hitherto no economical plan for the recovery of the salt has been devised, and consequently Mr Valentin’s proposed modification of Mr Weldon’s process has failed to be adopted.

b. A second process for obtaining chlorine, called “the magnesia process,” has been devised by Mr Weldon. In the previous method, or “lime process,” two thirds of the chlorine contained in the hydrochloric acid, as we have seen, is lost, passing away in the form of waste chloride of calcium.

In the “magnesia process” all the chlorine is utilised, the acid employed being made to yield the whole of its gas in the free state. The regeneration of the manganese peroxide being likewise accomplished, and the process being a continuous one, theoretically no loss of material should take place.

Beyond the employment of liquor pumps, no machinery is requisite for carrying out the operation, which, being very simple in its details, requires the employment of little skilled and, consequently, expensive labour. Further, the inventor claims for it the production of bleaching powder at a less cost per ton than by any other process. The “magnesia method” is worked as follows:—

The spent liquors of the still, consisting of chloride of manganese and free hydrochloric acid, are neutralised with magnesite, or, as it is sometimes called, Greek stone—a very pure native form of carbonate of magnesia. Sometimes the magnesite is calcined, and the magnesia thus obtained used instead.

The neutralisation may be effected either in the still itself, or in a well made of cast iron. The liquid is next pumped into the settlers, in which it deposits its ferric and aluminic oxides and sulphate of lime. The clear liquor containing the chlorides of manganese and magnesia is then run into an iron evaporating pan, where it is concentrated by boiling until it reaches a temperature of between 300° and 320° F. At this point the magnesium chloride begins to be decomposed by the water, and hydrochloric acid is given off. When it has reached the above degree of concentration, it is conveyed into a muffle furnace. This furnace is divided into two compartments, separated by an iron door, which can be opened or shut by means of a pulley placed outside. The desiccation of the mass which is accompanied with the evolution of a little chlorine and a large amount of hydrochloric acid, having been completed in one of the divisions of the furnace, it is broken up by constant stirring into thin cakes and raked into the second division, where it is gently heated with access of air; when the operation is complete the residue which left the first compartment as a mixture of manganese and magnesium chloride becomes converted into manganate of magnesia (MgMnO3), its chlorine having been driven off partly in the free state and partly as hydrochloric acid. “As long as water is present in the furnace hydrochloric acid is evolved, and as the main evaporation takes place in the first division of the furnace, it is chiefly hydrochloric acid that is there generated. In the second division it is chiefly chlorine which is evolved, but it is, of course, mixed with some hydrochloric acid. It is, indeed, doubtful whether much manganese chloride is decomposed by the water so long as there remains any chloride of magnesium, as this body is far more readily decomposable.”

It is stated that all the manganese is not converted into peroxide in the furnace, but that a certain portion of it is left as protoxide; which, with the magnesia, constitutes the useless “bases.” The completion of the process is known when portions of the cake drawn from time to time from the furnace cease to indicate any increase in the quantity of peroxide of manganese.

The finely-divided black powder—manganate of magnesium—thus obtained, after leaving the furnace and when sufficiently cold, is ready for the stills—where, in contact with hydrochloric acid, it is again employed in the generation of chlorine.

The chlorine leaves the furnace mixed with much hydrochloric acid, nitrogen, and air. The gaseous mixture is drawn by a chimney draught through the coke towers, as in the making of salt-cake. By this contrivance the hydrochloric acid is recovered, yielding a solution strong enough to react upon fresh manganese in the still. The diluted chlorine may be made to ascend leaden towers, where it comes in contact with a shower of milk of lime, which absorbs the gas and forms ordinary bleaching liquid, whilst sometimes it is employed in the production of potassium chlorate.

We have seen that the chlorine yielded by the “magnesia process” is partly in the concentrated, and partly in the dilute condition. The ratio of strong chlorine generated in the still to that of weak chlorine produced in the furnace may be anything between one to one, and one to about four, at pleasure.

“When working so as to obtain strong chlorine and weak chlorine in about equal proportions, the quantity of the liquor to be boiled down per ton of total bleaching powder made was about 105 cubic feet. As the proportion of the weak chlorine increased, the quantity of liquor to be boiled down diminished until, when the proportion of the weak chlorine to that of the strong became as four to one, the quantity of liquor to be boiled down per ton of total bleaching powder made was only about 40 cubic feet.”

11. (Deacon.) As we have already seen, Vogel proposed to obtain chlorine by the decomposition by heat of cupric chloride, and to reconvert the resulting cuprous chloride into the cupric salt by treatment with hydrochloric acid.

Chlorine may be produced by passing a mixture of gaseous hydrochloric acid and air over heated bricks or other porous substances, a reaction which Oxland unsuccessfully attempted to turn to account for the production of chlorine for manufacturing purposes. The cause of failure appears to have been the great heat necessary to effect the decomposition of the acid atmospheric oxygen.

In the late Mr Deacon’s process both Vogel’s and Oxland’s methods are combined. He discovered that to be able to generate chlorine and water from gaseous hydrochloric acid and air, a very much lower temperature than that employed by Oxland was necessary, and he found that this diminished temperature could be attained, if the gas and air to be decomposed were passed over porous bricks saturated with a solution of sulphate of copper, and heated to a temperature of 700° to 750° F.

Beyond this point he found the heat ought not to be carried; for at 800° the cupric chloride formed begins to volatilise, and to condense in the cooler parts of the apparatus (presently to be described), thereby interfering with the draught through it, and delaying the working, since its removal becomes necessary. It was found that below 400° the reaction does not take place. Experience has demonstrated that the best temperature to effect this decomposition is 625° F.

The hydrochloric acid obtained either from a soda furnace or evolved from an aqueous solution is immediately mixed with a quantity of air containing an excess of oxygen over that required for liberating all the chlorine from the evolved hydrochloric acid, and passed through heated U-shaped tubes of cast-iron, from which the gaseous mixtures obtain the necessary temperature. The original plant was so contrived that the heated gases were conveyed from the U-shaped tubes into a series of nine towers made of iron or other suitable material. Entering by a pipe at the bottom of the first tower, and passing on to the second, the gases came into contact with a series of ordinary agricultural drain pipes of small bore arranged with vertical spaces, these pipes being saturated with a solution of sulphate of copper and sulphate of soda, it being subsequently found that this latter addition increased the efficacy of the copper sulphate, as well as its power to resist decomposition. From the first two towers of the series the mixed gases traversed the remaining ones, where they encountered small pieces of common brick, fire brick, or burnt clay also impregnated with the copper and soda sulphates, after reacting upon which they passed out of the apparatus, called the ‘decomposer,’

In the more recently made decomposers we believe the nine towers were abolished, and one chamber substituted for them, the drain-pipes being at the same time abandoned for pieces of brick and clay marbles.

A decomposer upon this latter principle is said to have been in use for several months at a factory in Berlin, and to have worked perfectly satisfactorily. After leaving the decomposer, the gaseous mixture, which now consists of chlorine, water, nitrogen, unconsumed oxygen, and undecomposed hydrochloric acid, after being cooled, is passed through water, by which means it is deprived of its hydrochloric acid.

It is next made to ascend a tower, where, meeting with a stream of sulphuric acid running over coke, it is deprived of its water. The chlorine (diluted with nitrogen and oxygen) is now ready for the lime chamber.

One great objection urged against the adoption of the above process, viz., that in consequence of the large volume of the evolved gases enormously large chambers for the preparation of the bleaching would be necessitated, seems to have been met by passing the gas through a series of chambers, in which the first contains nearly finished bleaching powder; the second, lime in a less saturated condition; and so on, until the last chamber contains merely slaked lime.

The following table, exhibiting the amount of chlorine contained in different batches of bleaching powder made by Deacon’s process, is extracted from ‘Chemistry, Theoretical, Practical, and Analytical,’ published by Mackenzie:—

Strength. Strength.

July 14 36·0 July 22 34·3

” 15 34·8 ” ” 36·5

” ” 36·1 ” 24 36·8

” 17 36·4 ” ” 37·5

” ” 36·0 ” 25 36·1

” 18 37·2 ” ” 36·7

” ” 37·9 ” ” 36·8

” 19 37·2 ” 26 36·2

” ” 37·0 ” ” 36·9

” 20 37·9 ” 27 36·9

” ” 36·7 ” ” 35·5

” 21 36·0 ” 28 37·2

” ” 35·3 ” ” 37·0

” ” 37·7 ” ” 36·75

Writing on this process in his late work, ‘The Alkali Trade,’ Mr Kingzett says:—“The process bearing Mr Deacon’s name was first brought before the public at the British Association Meeting in 1870.

“It excited at that time much attention, and indeed for some period it was doubtful whether it would not rival or even displace the Weldon process. Further experience, however, discovered difficulties in the practical working of this beautiful method, which exercise a deteriorating influence on its value, and lessen its applicability. Although several plants have been erected in connection with this mode of manufacturing chlorine, most of them have been since abandoned, and at the present time most of the chlorine is manufactured according to the process of Mr Weldon.”

Dr Jurisch, in a communication to ‘Dingler’s Polytechnic Journal,’ 1876, remarks that when Deacon’s process was first taken up within a short time by more than twelve English and two German establishments, the view was generally entertained that the balls of clay steeped in solution of copper would ensure an uninterrupted production of chlorine gas for a year or two, if not longer. Before many months had elapsed complaints were heard of the action of the balls. He, therefore, undertook to determine what can be the cause of these balls declining so rapidly in their efficacy. His conclusion is, that the true cause of this speedy decrease in the decomposition is due to sulphuric acid, which passes through the interstices of the clay-balls mixed with the other gases. This injurious action, according to Hasenclever and Sartori, is probably to be explained by the following reaction:—The vapour of sulphuric acid in contact with sulphate of alumina at a dull red-heat, as is found in the balls, is resolved into sulphurous acid, watery vapour, and oxygen; the sulphurous acid thus formed is reoxidised at the expense of the free chlorine, is again decomposed, and thus keeps up a destructive circulation in the apparatus, which reduces or totally checks the chlorine.

Prices of Bleaching Powder (Clapham).

In 1805 £120 0 0 per ton.

” 1810 84 0 0 ”

” 1815 80 0 0 ”

” 1820 47 0 0 ”

” 1825 27 0 0 ”

” 1830 23 0 0 ”

” 1832 21 0 0 ”

” 1835 23 0 0 ”

” 1840 21 0 0 ”

” 1846 18 0 0 ”

” 1850 13 15 0 ”

” 1855 10 15 0 ”

” 1857 13 10 0 ”

” 1860 11 0 0 ”

” 1868 10 12 0 ”

Prop., Uses, &c. Chlorine is a gas possessing a yellowish-green colour, and a pungent, suffocating odour. It is one of the heaviest substances that are gaseous at ordinary temperatures, being nearly 2⁄2 heavier than atmospheric air; sp. gr. 1·47. It is soluble to a considerable extent in water, that liquid at 60° Fahr. absorbing about twice its volume. It is non-inflammable, but its union with some of the elements is attended with the phenomena of combustion; thus, phosphorus, copper leaf, powdered antimony and arsenic, and several other substances thrown into chlorine immediately inflame. Under a pressure of 4 atmospheres it is condensed into a yellow, limpid liquid. Moist chlorine gas cooled to 32° Fahr. condenses into yellow crystals, containing 35⁄2 parts of chlorine and 90 parts of water. The most remarkable property of chlorine is its power of destroying almost all vegetable and animal colours, and the putrid odour of decomposing organic matter; hence its value as a bleaching agent, and as a disinfectant and fumigator. When first proposed as a bleaching agent by Berthollet, it was used much the same way as sulphur is now in bleaching woollen goods; afterwards a solution of the gas in water was employed, but the final improvement was Tennant’s patent of combining the gas with lime to form “chloride of lime.” With the bases chlorine forms an important series of compounds called chlorides.

Tests. Free chlorine is readily distinguished from other gases by its colour, suffocating odour, and bleaching properties. The aqueous solution dissolves gold leaf, and with nitrate of silver gives a white, curdy precipitate.

CHLORINE STILLS. The accompanying figure represents a section of one of the earlier forms of still used in the preparation of chlorine.

These stills were sometimes made of strong sheet lead, the lower part of which was enclosed in a jacket of cast iron, into which steam was forced, by which means the contents of the still were heated. The steam was injected from an ordinary boiler through the pipe H, and the materials, after the decomposition had been completed, were drawn off by the pipe G. The four openings, C, D, E, F, were secured by water lutes, capable of bearing a pressure greater than that required in the chamber where the saturation took place. In some cases the lower half of the still was made of cast iron, and fitted into a groove made in the upper part, the two sections being united by means of a strong cement. In the latter case the heating of the still was effected by a naked fire applied to the bottom. Into the orifice C the said materials employed were introduced, whilst the acid was poured through the opening F. The gas evolved passed off through the pipe E to the purifier and chamber, where it was absorbed by the lime, and converted into bleaching powder, and the shaft of the agitator passed up through D.

The use of the leaden stills survived for a longer time in France than in this country. In some parts of Germany large glass globes with long necks were employed, in which the chlorine was generated from a mixture of hydrochloric acid and manganese. But these were only applicable in cases where comparatively small quantities of bleaching powder were to be manufactured. When the chlorine is obtained from a mixture of manganese, common salt, and sulphuric acid, the apparatus, being required to withstand a greater heat, is made entirely of metal.

In fig. 2. a a represents a shallow iron pan, fitted with the tube b, for the purpose of emptying the contents of the leaden cylinder d d. This iron vessel serves as the lower part of the cylinder d d, the top of which is provided with an opening for a funnel syphon tube, for the introduction of the acid, and another opening, f, for the manganese. The entire apparatus stands on a flue leading from the furnace.

The foregoing drawing represents a vessel for the manufacture of chlorine on a large scale, and is extensively used in Germany.

It consists of a cylindrical vessel of sandstone, the lower half of which, A, is carved out of a single block; the upper half, B, also of one piece, fits into the lower by means of a grooved joint, the two parts being united by means of a cement made of clay and boiled linseed oil. About six inches from the bottom the cylinder widens by 2 inches, and the rim thus formed carries a perforated bottom, C, upon which the manganese is deposited in large lumps. The tube D, likewise of stone, passes beneath the perforated bottom, and is at the other end joined to the steam-tube E. The steam must therefore, when introduced, enter the cylinder through the perforations of the false bottom. The top of the cylinder is closed by a lead cover, K, which is fastened down by means of iron clamps; this lid has an aperture, G, and the tubes E, F, H, pass through it; tube E serves, as already stated, for the introduction of the steam; tube F is for the delivery of chlorine; the bent tube, H, which ends in a funnel, for the introduction of the hydrochloric acid; and the opening G for throwing the lumps of manganese into the cylinder. The solution of manganese chloride, resulting from the action of the hydrochloric acid upon the manganese, is removed through I, which is kept closed by a wooden stopper whilst the reaction proceeds.

See also, under Chlorine, the description of Weldon’s stills, and of Deacon’s apparatus.

CHLORITE. A salt in which the hydrogen of chlorous acid, HClO2, is replaced by a metal or other basic radical. See Chlorous Acid.

CHLOROCHROMIC ACID. CrOCl. Syn. Chlorochromic anhydride. Prep. Bichromate of potassium, 3 parts; common salt, 3⁄2 parts; are intimately mixed together, put into a glass retort, and oil of vitriol, 9 parts, added; heat is next applied and maintained as long as dense, red vapours are given off. The product in the receiver is a heavy, deep-red liquor, greatly resembling bromine in appearance. Water resolves it into hydrochloric and chromic anhydride.

CHLORODYNE. See Patent Medicines.

Chlorodyne (Dr Browne’s). Acid muriat. conc., 5 parts; ether, chloroform, tinct. cannab. Ind., tinct. capsici, of each 10 parts; morphia, prussic acid, of each 2 parts; oil of peppermint, 1 part; syrup, 50 parts; tinct. hyoscyami, tinct. aconiti, of each 3 parts.

Chlorodyne, English. A filtered mixture of 5 grammes tinct. aromat., 4 grammes tinct. opii simp., 1 gramme morph. mur., 10 grammes aq. amygd. amar., 80 grammes syrup of liquorice, 1 gramme extract of liquorice, 40 grammes 90 per cent. spirit of wine, 5 drops oil of peppermint, 10 drops ether, 30 drops chloroform.

CHLOROFORM. CHCl3. Syn. Terchloride of formyle, Formyl-chloride; Chloroformyl, Trichloromethane, Chloroformum, L. A remarkable fluid discovered by Liebig in 1830, and independently by Soubeiran in 1832, and carefully examined in 1834 by Dumas. In 1842 its action upon animals was investigated by Dr M. Glover, and in 1847 it was introduced to the medical profession as an anæsthetic agent by Dr Simpson of Edinburgh.

It was first obtained by the action of caustic alkali upon chloral, but it is more easily prepared by distilling alcohol or wood spirit with chloride of lime. It may also be procured from wood spirit, acetone, oil of turpentine, and several essential oils, as well as from amylic alcohol, acetic acid, tartaric acid, and phenol; when these different bodies are severally subjected to the action of chloride of lime. When chlorine is made to act on marsh gas, or when chloral is treated with an alkali, chloroform is also produced.

Prep. 1. Chloride of lime (in powder), 4 lbs.; water, 12 lbs.; mix in a capacious retort or still, add of rectified spirit, 12 fl. oz., and cautiously distil as long as a dense liquid, which sinks in the water it passes over with, is produced; separate this from the water, agitate it with a little sulphuric acid, and, lastly, rectify it from carbonate of barium.

2. Chloride of lime, 4 lbs.; water, 10 pints; rectified spirit, ⁄2 pint; proceed as last, using a spacious retort that the mixture will only 1-3rd fill, and the heat of a sand bath. When ebullition commences remove the fire as quickly as possible, lest the retort be broken by the suddenly increased heat, and let the solution distil into a receiver as long as there is nothing which subsides, the heat being restored if it be at all needed. Add to the distilled liquid four times as much water, and shake the whole well together; next cautiously separate the heavier part as soon as it has subsided, and to this add chloride of calcium, broken into fragments, 1 dr.; and shake occasionally during an hour; finally, let the fluid again distil from a glass retort into a glass receiver.

3. Hydrate of lime, 1 part, is suspended in cold water, 24 parts, and chlorine passed through the mixture until nearly the whole of the lime is dissolved; hydrate of lime, q. s. just to restore the alkaline reaction of the liquid, is then added; and, afterwards, rectified spirit of wine or wood spirit, 1 part, is mixed in; the whole, after repose for 24 hours in a covered vessel, is cautiously distilled as before.

4. (B. P.) Take of chlorinated lime 10 lbs.; rectified spirit, 30 fluid ounces; slaked lime, a sufficient quantity; water, 3 gallons; sulphuric acid, a sufficient quantity; chloride of calcium in small fragments 2 oz.; distilled water, 10 fluid ounces. Place the water and the spirit in a capacious still, and raise the mixture to a temperature of 100° F. Add the chlorinated lime, and 5 lbs. of the slaked lime, mixing thoroughly. Connect the still with a condensing worm, encompassed by cold water, and terminating in a narrow-necked receiver; and apply heat so as to cause distillation, taking care to withdraw the fire the moment that the process is well established. When the distilled product measures 50 fluid ounces the receiver is to be withdrawn. Pour its contents into a gallon bottle, half filled with water; mix well by shaking, and set it at rest for a few minutes, when the mixture will separate into two strata of different densities. Let the lower stratum, which contains crude chloroform, be washed by agitating it in a bottle with 3 fluid ounces of the distilled water. Allow the chloroform to subside, withdraw the water, and repeat the washing with the rest of the distilled water, in successive quantities of 3 oz. at a time. Agitate the washed chloroform for five minutes in a bottle with equal volume of sulphuric acid, allow the mixture to settle, and transfer the upper stratum of liquid to a flask, containing the chloride of calcium, mixed with ⁄2 oz. of slaked lime, which should be perfectly dry. Mix well by agitation. After the lapse of an hour connect the flask with a Liebig condenser, and distil over the pure chloroform by means of a water bath. Preserve the product in a cool place in a bottle furnished with an accurately ground stopper. The lighter liquid which floats on the crude chloroform after its agitation with water, and the washings with distilled water, should be preserved and employed in a subsequent operation. Sp. gr. 1·456.

Prop., &c. Liquid; transparent; colourless; odour fragrant, ethereal, and apple-like; taste ethereal, sweetish, but slightly acrid; soluble in 2000 parts of water; mixes in all proportions with alcohol and ether; dissolves (readily) bromine, camphor, caoutchouc, gutta percha, iodine, oils, resins, wax, and several other like substances; boils at 141·8° Fahr.; kindles with difficulty; burns, when strongly heated, with a greenish flame; and communicates a dull, smoky-yellow colour to the flame of alcohol. Sp. gr. 1·48 (1·497, Miller); density of vapour 4·2. The vapour has the remarkable property of rendering a person breathing it temporarily insensible to pain.

Chloroform is frequently adulterated with alcohol and ether; and owing to careless manipulation, is also sometimes contaminated with other substances, as chloral, hydrochloric acid, free chlorine, aldehyde and certain chlorinated oils. These latter compounds are not only the most objectionable and prejudicial of the impurities found in chloroform, but if present in it to any appreciable extent, they render its anæsthetic administration not only inefficient, but frequently absolutely dangerous. These deleterious chlorinated oily compounds may be removed by agitation with strong sulphuric acid, or by distillation from it. Chloroform made from wood spirit is said to be more impure than that from alcohol. When pure it is free from colour, and of a pleasant odour. It is not perfectly soluble in water; and does not turn the colour of litmus red. Rubbed on the skin it quickly evaporates, scarcely leaving any odour. Dropped into water, it falls to the bottom and remains bright and limpid; but if it contain alcohol the surface of the drop becomes opaline. If the same experiment be made with diluted sulphuric acid, sp. gr. 1·44, the drop of pure chloroform will fall to the bottom; but that which contains spirit, if not shaken, will float or remain suspended in the acid solution. When contaminated with heavy hydrocarbon oils, a drop evaporated from the palm of the hand leaves behind a strong smell. Hydrochloric acid and free chlorine are detected by the ordinary tests.

Mr Shuttleworth, writing to the ‘Canadian Pharmaceutical Journal,’ says:—“In regard to the restoration of chloroform which has become spoiled, I would recommend that the chloroform be well agitated with a dilute solution of hyposulphite of soda.

“It should then be separated by means of a glass funnel from the supernatant liquid, and again washed; this time with simple water. After being separated the chloroform should be passed through filtering paper to free it from traces of moisture, when it will be found much improved and comparatively sweet, good enough in any case for external use.

“There are, of course, certain other impurities of chloroform which the hyposulphite will not remove. These are of a more stable character, and as they possess a higher boiling point than chloroform, may be separated by distillation, or by treatment with sulphuric acid in the usual manner.”

Uses, Action, &c. Chloroform is anodyne, antispasmodic, sedative, stimulant, and anæsthetic. In small doses (5 to 12 or 15 drops, in water, mixed with a little syrup or mucilage) it is employed in spasmodic disorders, and as a stimulant and diaphoretic. It is now chiefly used as an anæsthetic to produce insensibility to pain during surgical operations. The dose for inhalation is 1 fl. dr., which is repeated, in a few minutes, if no effect is produced, until 3 fl. dr. have been thus exhibited; the effects being carefully watched, and the source of the chloroform vapour removed as soon as a sufficient degree of anæsthesia is produced, or any unpleasant symptoms develop themselves.

Chloroform in large doses depresses the heart’s action, and causes profound coma, and death. It is therefore dangerous in all cases complicated with diseases of the heart or brain, or any visceral affections of a congestive character.

The treatment of asphyxia from chloroform is—the horizontal position, cold affusion to the head and spine, artificial respiration, and, if possible, either the application of electricity, or the inhalation of protoxide of nitrogen or oxygen gas, largely diluted with atmospheric air.

Concluding Remarks. The preparation of chloroform is not unattended with danger, and frequently miscarries in careless or inexperienced hands. This arises chiefly from the violent reaction which immediately follows the application of the heat. The common plan is attended with danger of explosion, or of the liquid in the still being forced over into the receiver, owing to the extraordinary rapidity with which the vapours are eliminated, and the ingredients, in consequence, swell up. A method which is successfully adopted on the large scale is to employ a very broad and shallow capsule-shaped still, having a flat rim round it, with a head or capital furnished with a corresponding rim at its lower part. In use, a flat, endless band of vulcanised india rubber is placed between the two rims, which are then held air-tight together by means of small, iron clamps. The application of heat is also delayed for some time after the admixture of the spirit with the other ingredients, and the process is interrupted as soon as the first violence of the reaction has subsided, by which time the whole product of chloroform will have passed over into the receiver. If the distillation is continued beyond this point, the remaining product is water. On the small scale, a very capacious, flat-bottomed retort or cucurbit should be employed. A similar condenser may be used to that noticed under ether.

CHLOROFORMIC ANODYNE (George Harley) is said to be an alcoholic tincture of opium with prussic acid and chloroform.

CHLOROHYPONITRIC GAS (NOCl) and CHLORONITROUS GAS (N2O2Cl4 are two peculiar compounds, formed when nitric acid and hydrochloric acid are mixed.

CHLOROMETER. Syn. Chlorim′eter. An instrument or apparatus employed in chlorometry. The chlorometers in common use are graduated measures and tubes precisely similar to those used in ACIDIMETRY, ALKALIMETRY, &c.

CHLOROMETRY. Syn. Chlorim′etry. The estimation of the available chlorine in the bleaching powder of commerce, which is valued and sold in this country by its per-centage of that element. The plans generally adopted are applicable to the so-called chlorides of soda and potassa, as well as to the ordinary bleaching powder, chloride of lime. Most of them depend on the oxidising effect of water when undergoing decomposition through the action of chlorine.

Dalton’s Process. The test solution is prepared as follows:—Pure protosulphate of iron (previously dried by strong pressure between the folds of cloth or bibulous paper), 78 gr., are dissolved in distilled water, 2 oz., and a few drops of hydrochloric or sulphuric acid added. This quantity of protosulphate requires for complete peroxidation just the quantity of oxygen liberated by 10 gr. of chlorine; in other words, the solution exhibits the indirect effect produced by exactly 10 grains of the bleaching element.

Exactly 50 gr. of the sample of chloride of lime to be examined are next weighed, and well mixed in a glass or wedgwood mortar with tepid water, 2 oz.; and the mixture poured into a graduated tube or chlorometer. The tube is next filled up to 0, or zero, with the washings of the mortar, and the whole well mixed, by placing the thumb over the orifice and shaking it. The solution of chloride of lime, thus formed, is next gradually and cautiously added to the solution of sulphate of iron, previously noticed, until the latter is completely peroxidised, which may be known when it ceases to be affected by a solution of red prussiate of potash. When a drop of the latter test, placed upon a white plate, ceases to give a blue colour on being touched with the point of a glass stirrer or rod dipped in the liquor under examination, enough of the solution of the chloride has been added. The number of measures thus consumed must now be carefully read off from the graduated scale of the chlorometer, from which the richness of the sample may be estimated as follows:—As 100 of the chlorometer divisions contain exactly 50 gr. of the chloride under examination, each measure will contain only ⁄2 gr., and, consequently, the number of measures consumed will represent half that number of grains of the chloride examined; and the weight of the chloride thus used will have contained 10 gr. of chlorine—the constant quantity of that substance required to peroxide the test solution of sulphate of iron. Thus:—If 80 measures of the liquor in the chlorometer have been consumed, this quantity will represent 40 gr. of chloride of lime, and 10 gr. of chlorine. By dividing 1000 by this number, the per-centage of chlorine will be obtained. In the present instance this would be—

1000
—— = 25%
40

Crum’s Process. Equal weights of water and hydrochloric acid are mixed together, and cast-iron borings digested in the diluted acid until saturation is complete; a large excess of iron being purposely employed, and the liquid kept at the heat of boiling water for some time. One measure of the solution, marking 40° on Twaddell’s scale (sp. gr. 1·200), is then mixed with an equal quantity of acetic acid (sp. gr. 1·048). This forms the test-liquid. When mixed with 6 or 8 parts of water it is quite colourless, but chloride of lime occasions the production of peracetate of iron, which gives it a red colour.

The above proof-solution is next poured into 12 two-oz. vials, of exactly equal diameters, to the amount of ⁄9th of their capacity; these are filled up with bleaching liquid of various strengths; the first at ⁄12th of a degree of Twaddell, the second ⁄12ths, and so on up to ⁄12ths of 1°. They are then well corked up, and, after agitation, arranged side by side on a tray, furnished with holes to receive them. (See engr.) To ascertain the strength of an unknown sample of bleaching liquor, the proof-solution of iron is put into a phial, exactly similar to the 12 previously used, and in precisely the same proportion (⁄9th). The phial is then filled up with the bleaching liquor, well shaken, and placed beside that one of the 12 already prepared which it most resembles in colour. The number on that phial expresses the strength of the sample under examination, in twelfths of a degree of Twaddell’s hydrometer.

Obs. The preceding method is admirably suited for weak solutions, such as are employed for bleaching textile fabrics, and is well adapted (from its simplicity) to the purposes of practical men. Indeed, it is quite astonishing to see with what ease and accuracy it is applied by unlettered operatives. This gives it great practical value. It has been for some time in extensive use in the bleaching houses of Scotland.

Table exhibiting the quantity of Bleaching Liquid, at 6° on Twaddell’s scale (sp. gr. 1·030), required to be added to a weaker liquor, to raise it to the given strengths. Adapted from Mr Crum’s table by Mr Cooley.

Strength of Sample in ⁄12°. Required Strength. Proportions required.

Given Sample. Liquor at 6°.

Parts. Part.

Water. ⁄12° 8 1

1 ” 9⁄4 1

2 ” 11 1

3 ” 13⁄2 1

4 ” 17 1

5 ” 23 1

6 ” 35 1

7 ” 71 1

Water. ⁄12° 11 1

1 ” 13⁄2 1

2 ” 17 1

3 ” 23 1

4 ” 35 1

5 ” 71 1

Water. ⁄12° 17 1

1 ” 23 1

2 ” 35 1

3 ” 71 1

Water. ⁄12° 23 1

1 ” 35 1

2 ” 71 1

According to Mr Crum, the range of strength within which cotton is “safe” is very limited. A solution at 1° of Twaddell’s scale (sp. gr. 1·005) is not more than safe, while one at ⁄2° is scarcely sufficiently strong for the first operation on stout cloth, unless it is packed more loosely than usual.

Gay-Lussac’s Indigo Process. One part of the best indigo is dissolved in 9 parts of strong sulphuric acid by the aid of a gentle heat; this solution is then mixed with distilled water, in such proportion that 1 volume of chlorine gas shall exactly decolour 10 volumes of this solution. Each measure so decoloured is called a degree, and each degree is divided into fifths. 5 gr. of the best chloride of lime, dissolved in 500 gr. measures of water, possess the above power, and indicate 10° or proof; or in other words, will decolour 10 times its volume of the indigo solution.

Obs. This method of chlorometry is objectionable, and liable to error, from the indigo solution altering by keeping. When, however, the proper precautions are used, it may be safely trusted for weak bleaching liquors.

Arsenious Acid Process. This depends on the conversion, by oxidation, of arsenious acid into arsenic acid, in the presence of chlorine and water.

To prepare the test-liquor, pure arsenious acid, 100 gr., are dissolved in about 4 fl. oz. of pure hydrochloric acid (free from sulphurous acid), and the solution diluted with water until, on being poured into a graduated 10,000 grains-measure-glass, it occupies the volume of 7000 grains measure marked on the scale. Each 1000 grains measure of this liquid now contains 14·29 gr. of arsenious acid; corresponding to 10 gr. of chlorine, or ⁄10th gr. of chlorine for every division or degree of the scale of the chlorometer.

100 gr. of the chloride of lime to be examined are next dissolved in water as before, and poured into a tube graduated up to 2000 grains measure. The whole is now well shaken, in order to obtain a uniformly turbid solution, and half of it (1000-grains-measure) transferred to a graduated chlorometer, which is, therefore, thus filled up to 0°, or the zero of the scale, and contains exactly 50 gr. of the chloride of lime under examination; whilst each degree or division of the scale contains only ⁄2 gr.

1000 grains measure of the arsenious acid test-liquor are now poured into a glass beaker, and a few drops of solution of sulphate of indigo added in order to impart a faint but distinct blue colour to it; the glass is then shaken so as to give a circular movement to the liquid, and whilst it is whirling round, the chloride-of-lime solution from the chlorometer is gradually and cautiously added, until the blue tinge given to the arsenious acid test-liquor is destroyed; care being taken to stir the mixture well during the whole process, and to stop as soon as the decolorisation is completed.

Let us suppose now that, in order to destroy the blue colour of the 1000 grains measure of the arsenious acid test-liquor, 90 divisions or degrees of the chloride-of-lime solution have been employed. These 90 divisions, therefore, contained the 10 gr. of chlorine required to destroy the colour of the test-solution; and since each division represents ⁄2 gr. of chloride of lime, 45 gr. of chloride of lime (10 gr. of chlorine) were present in the 90 divisions so employed, from which the per-centage strength may be ascertained. For—

45 : 10 : : 100 : 22·22

The chloride of lime examined, therefore, contained 22⁄4 per cent, (nearly) of chlorine.

Obs. This method is extremely simple and trustworthy when properly employed; but to ensure accuracy, certain precautions must be adopted. Instead of pouring the test-liquor into the solution of the sample (as in alkalimetry), the solution of the sample must be poured into the test-liquor.

Vogel found that in a normal solution of arsenious acid that had been prepared for using in the above process, half the quantity of the arsenious acid became oxidised to arsenic acid in the course of about a year. He therefore recommends that the standard solution, if kept for some time, should be tested by a magnesium salt. The formation of a precipitate would show the solution had undergone such a change, as to render it unfit for volumetric estimations.

Penot’s Process. This is a modification of the previous process. For the arsenious acid solution arsenite of soda is substituted, and for the indigo solution a colourless iodised paper, which is turned blue by the smallest quantity of free acid. The paper is prepared in the following manner:—1 gram of iodine, 7 grams of carbonate of soda, 3 grams of starch, and a quarter of a litre of water are mixed. When the solution becomes colourless it is diluted to half a litre; in this fluid, white paper is soaked. The arsenical fluid is prepared by dissolving 4·44 grams of arsenious acid, and 13 grams of crystallised carbonate of soda in 1 litre of water. This solution is added by means of a burette to the solution of chloride of lime intended to be tested (10 grams of the sample to 1 litre) the completion of the reaction being known by the paper remaining uncoloured.

Lunge says that the same piece of moist iodine test paper may be made use of repeatedly, since the spots produced by testing usually disappear after about twenty-four hours if exposed to the air. The paper must, however, be kept away from dust.

Wagner’s Process. This method is based upon the fact that a solution of chloride of lime separates the iodine from a weak (1 to 10) and slightly acidified iodide-of-potassium solution, the iodine being quantitatively estimated by means of hyposulphite of soda:—

Iodine 21, yield Iodine of sodium, 2NaI,

Hyposulphite of Tetrathionate of sodium, Na2S4O6,

soda, 2Na1SO3 Water, 5H2O.

+5H2O,

The test is performed as follows:—100 c. c. =1 gram of bleaching-powder solution, obtained by dissolving 10 grams of chloride of lime in 1 litre of water, are mixed with 25 c. c. of solution of iodide of potassium acidified with dilute hydrochloric acid. The resulting clear, deep brown-coloured solution is treated with hyposulphite of soda solution until quite colourless. The hyposulphite of soda solution is composed of 24·8 grams of that salt to 1 litre of water; 1 c. c. of this solution neutralises 0·0127 grams of iodine, and 0·00355 grams of chlorine.

Otto’s Process. This method is based upon the following data. Two molecular weights of protosulphate of iron when brought into contact with chlorine, in presence of water, and free sulphuric acid, give one molecule of persulphate of iron, and two molecules of hydrochloric acid, the process consuming one molecule of chlorine. Two molecules of crystallised sulphate of iron = 556, correspond to 71·0 of chlorine, or in other terms 0·7839 grams of the crystallised sulphate correspond to 0·1 gram of chlorine.

Bunsen’s Process. This consists in adding iodide of potassium to the bleaching-powder liquor, acidulating the mixture with hydrochloric acid, and running the solution of arsenite of soda into it till only a yellow tint shows itself. A little starch paste is now added, and the arsenite solution cautiously introduced drop by drop, till the blue colour just disappears. The solutions must all be standardised. To preserve the starch paste Mohr advises the addition to it of a little chloride of zinc.

Mr Davies uses glycerin as a solvent for the arsenious acid. He prepares a standard solution as follows:—13·95 grains of arsenious acid in 40 c. c. of glycerin and fitted up to 1 litre. Every c. c. corresponds to 0·1 grain of chlorine. Indigo sulphate solution is used as an indicator, and the bleaching liquor is run into the glycerin solution until the blue colour of the latter is changed to a brownish yellow.

Dr Ure’s as follows:—Liquor of ammonia, of a known strength, tinged with litmus, is added to a solution of a given weight of the chloride under examination, until the whole of the chlorine is neutralised, which is known by the colour being destroyed. From the quantity of ammonia consumed the strength of the sample is estimated.

The value of bleaching powder is estimated in England, America, and Germany by degrees corresponding to the per-centage of available chlorine contained in a sample of chloride of lime by weight; but in France the degrees denote the number of litres of chlorine gas at 0° c. and 760° Mm. Bar., which 1 kilo of bleaching powder can evolve. In the following table the chlorometrical degrees of France and England are contrasted:—

French. English.

63 20·02

65 20·65

70 22·24

75 23·83

80 25·42

85 27·01

90 28·60

100 31·80

105 33·36

110 34·95

115 36·54

120 38·13

125 39·72

126 40·04

The per-centage may be calculated by multiplying the French degrees by the coefficient 0·318.

CHLOROCARBONIC ACID. (COCl2). Syn. Phosgene Gas, Carbonic oxydichloride. This compound may be produced by the direct combination of equal volumes of carbonic oxide and chlorine gases under the influence of sunlight (whence its name of “phosgene gas”), when the mixture gradually becomes colourless, and contracts to half its original volume. Chlorocarbonic acid has a peculiar pungent smell, and fumes strongly when exposed to moist air, the moisture of which it decomposes, producing at the same time hydrochloric and carbonic acids.

It is sometimes employed in chemical research for the removal of hydrogen from organic compounds, and the substitution of carbonic oxide, or its elements for the hydrogen.

CHLOROPHYLL. The green colouring matter contained in the leaves, stalks, unripe fruit, and juices of most plants.

CHLORO′SIS. Syn. Green sickness. A disease which principally affects young unmarried females.

Symp. Languor, listlessness, fatigue after the least exercise, palpitation of the heart, flatulency, indigestion, acidity of stomach and bowels, constipation (generally), appetite for unnatural food, general debility, &c. As the disease advances, the skin at first pale, assumes a peculiar greenish tint, the respiration becomes affected, the feet and legs swell, and various organic affections of the viscera ensue. During the early stages of this disease the catamenia are usually pale and scanty, and return at irregular intervals, and as it progresses they disappear altogether.

Treat. This should be tonic and restorative. That recommended under Anæmia may be adopted with advantage. See also Appetite, Atrophy.

Chlorosis, Electuary for—Female Electuary. A greenish-black thick syrup, consisting of sugar, bayberries, carbonate of iron, iron filings, and water. (Buchner.)

Chlorosis Powder—Female Powder—consists of a mixture of anise, sugar, and 14 per cent. of iron filings. (Wittstein.)

Chlorosis Powder—Female Powder, according to Schott and Strauss, is a mixture of violet root, gum Arabic, and a tasteless green powder with 33 per cent. of steel filings. According to Hager, it is composed of 2 parts ferri pulvis, with 3 parts powdered sweet-flag root.

Chlorosis Powder—Female Powders. Steel filings, starch powder, and knot grass, of each 1 part, Florentine orris root, 4 parts.

Chlorosis Powder—Female Powders. A mixture of 1 part steel filings and 2 parts of a vegetable powder composed of gum Arabic, Florentine orris, knot grass, &c. (Egb. Hoyer.)

Chlorosis Water (Dr Ewich) contains in 10,000 parts 11 of sodium carbonate, 9 of sodium chloride, 1⁄2 sodium sulphate, 7 calcium carbonate, and 1·2 iron carbonate with an excess of carbonic acid. (Hager.)

CHLOROUS ACID. HClO2. Syn. Acidum chloro′sum, L. Prep. From chlorate of potassium, 4 parts; arsenious anhydride, 3 parts; nitric acid, 12 parts; (diluted with) water, 4 parts; heated together in a glass flask, furnished with a bent tube, and placed in a water bath. It must be collected in the same way as chlorine, or passed into water, when it forms a solution of chlorous acid.

Prop., &c. Chlorous acid is a greenish-yellow gas, non-condensable by a freezing mixture of salt and ice, but liquefiable by extreme cold. The aqueous solution undergoes gradual decomposition, yielding chloric acid and chlorine. Chlorous acid possesses powerful oxidising and bleaching properties; with the bases it forms salts called CHLORITES. These are all soluble in water, and bleach like the acid. They may be recognised by the evolution of chlorous acid gas when acted on by an acid. The use of the arsenious acid is to deoxidise the nitric acid employed in the process. Tartaric acid, or other deodorising agent, may be substituted for it.

CHOC′OLATE. Syn. Chocola′ta, L.; Chocollati, Mexican; Chocolat, Fr. A beverage or paste made from the roasted seeds of the Theobroma Cacao, or Cocoa. Strictly speaking, the term “chocolate” is applicable to all genuine preparations of cocoa, but it is now generally used to distinguish those which contain sugar, and, commonly, flavouring substances. Of late years great attention has been paid to the manufacture of chocolate in England; our principal makers now import the finest descriptions of cocoa, and produce varieties of the manufactured article which are scarcely inferior to those of their French rivals. The different kinds of cocoa, and the processes of roasting, sweating, &c., are described under Cocoa, to which article we refer the reader also for particulars respecting the chemistry of chocolate.

Prep. The cocoa nibs are ground in a mill consisting of stone or metal rollers, which are usually heated either by charcoal fires or by steam, so as to soften or melt the natural fat. The warm, smooth paste which passes from the mill is then placed in a mixing mill, and incorporated with refined sugar, and usually vanilla or other flavouring substance. The trituration is continued until the whole paste is converted into an entirely homogeneous mass, which is finally shaped, by means of suitable moulds, into various forms, as blocks, loaves, tablets, lozenges, &c.

Obs. Chocolate, prepared as above, without the addition of aromatics, is known in the trade as PLAIN CHOCOLATE. The Spaniards flavour it with vanilla, cloves, and cinnamon, and frequently scent it with musk and ambergris. With these additions it is termed Spanish chocolate. In general, they add too large a quantity of the last four articles. The Parisians, on the contrary, use little flavouring, and that principally vanilla. They employ the best kinds of cocoa, and add a considerable quantity of refined sugar. So prepared, it is called French chocolate.

Proportions. 1. French Chocolate:—The proportions used for the best description are said to be—2 beans of vanilla, and 1 lb. of the best refined sugar, to every 3 lbs. of the choicest cacao nuts.

2. Spanish Chocolate:—The following forms are said to be commonly adopted:—

a. Caracas cocoa, 11 lbs.; sugar (white), 3 lbs.; vanilla, 1 oz.; cinnamon (cassia), ⁄4 oz.; cloves, ⁄2 dr.

b. Caracas cocoa, 10 lbs.; sweet almonds, 1 lb.; sugar, 3 lbs.; vanilla, 1⁄4 oz.

c. Caracas cocoa, 8 lbs.; island cocoa, 2 lbs.; white sugar, 10 lbs.; aromatics, as above.

d. Island cocoa, 7 lbs.; farina, q. s. to absorb the oil. Inferior.

3. Vanilla Chocolate. Syn. Chocolat à la vanille, Fr. A variety of French or Spanish chocolate highly flavoured with vanilla. The following proportions have been recommended:—

a. Caracas cocoa, 7 lbs.; Mexican vanilla, 1 oz.; cinnamon, ⁄2 oz.; cloves, 3 in no.

b. Best chocolate paste, 21 lbs.; vanilla, 4 oz.; cinnamon, 2 oz.; cloves, ⁄2 dr.; musk, 10 gr.

Obs. The vanilla used in making chocolate is reduced to powder by rubbing it with a little sugar before adding it to the paste.

Pur., &c. The chocolate commonly sold in England is prepared from the cake left after the expression of the oil, and this is frequently mixed with the roasted seeds of ground peas, and maize or potato flour, to which a sufficient quantity of inferior brown sugar, or treacle and mutton suet, is added to make it adhere together. Inferior sweet almonds are also employed in the same way.

Since the above paragraph was written there has been a vast improvement in English chocolates, though the cheaper sorts of certain makers are still much adulterated. Genuine chocolate should dissolve in the mouth without grittiness, and should leave a peculiar sensation of freshness; after boiling it with water the emulsion should not form a jelly when cold, for if it does starch or flour is present. The presence of animal fat may generally be detected by a cheesy or rancid flavour. See Cocoa.

Qual., &c. Chocolate is nutritive and wholesome if taken in moderation, but is sometimes apt to disagree with weak stomachs, especially those that are easily affected by oily substances or vegetable food. When this is the case, by adopting the simple plan recommended under Butter, chocolate may generally be taken with impunity, even by the dyspeptic. The quantity of aromatics mixed with the richer varieties of chocolate improve the flavour, but render them more stimulant and prone to produce nervous symptoms and head complaints.

Chocolate is taken in the solid form, or made into a beverage; or, combined with sugar, is made into various articles of confectionery.

Chocolate for the Table is prepared by slicing or scraping very finely the required quantity into a jug, and adding to it a small quantity of boiling water. This is worked into a thin, smooth paste, and the jug immediately filled up with boiling milk-and-water. A froth is produced by the same means that eggs are beaten up. The operation of “milling,” performed by rapidly twirling a notched cylinder of wood in the emulsion, raises the froth very quickly. Sugar may be put in with the scraped chocolate, or added afterwards at pleasure.

Chocolate should never be made for the table before it is wanted, because beating it again injures the flavour, destroys the froth, and separates the body of the chocolate, the oil of the nut being observed, after a few minutes’ boiling, or even standing long by the fire, to rise to the top. This is one of the principal reasons why chocolate offends the stomach.

Preparations of chocolate, intended either as nutritious articles of food for convalescents, or as vehicles for medicine, are common among the pharmacopœial and magistral formulæ of the Continent. The following are a few examples:—

Chocolate, Aromat′ic. Prep. (Weiglebt.) Cocoa beans and sugar, of each 16 oz.; cinnamon, ⁄2 oz.; cloves, 2 dr.; cardamoms and vanilla, of each 1 dr.

Chocolate, Car′rageen. See Chocolate, White (Nos. 1 and 2).

Chocolate, Chalyb′eate. Syn. Ferrugin′eous chocolate; Chocola′ta chalybea′ta, C. Mar′tis, L. Prep. 1. (Trousseau.) Spanish chocolate, 16 oz.; carbonate of iron, ⁄2 oz.; mix, and divide into 1-oz. cakes. One at a time; in anæmia, amenorrhœa, chlorosis, &c.

2. (Pierquin.) Iodide of iron, 2 dr.; chocolate, 16 oz. For ⁄2-oz. cakes; as above, and in scrofulous and glandular affections.

Chocolate, Guarana′. Syn. Paullin′ia chocolate; Chocola′ta paulin′iæ, C. guaran′æ, L. Prep. From guarana and white sugar, of each 1 oz., triturated together, and afterwards thoroughly mixed with good plain chocolate, 18 oz. Recommended as a restorative in debility, chlorosis, and other diseases of debility, especially those of a nervous character.

Chocolate, Ice′land Moss. Syn. Chocola′ta cetrar′iæ island′icæ, C. lichen′is, L. Prep. 1. (P. C.) Simple chocolate (P. C.), 32 parts; sugar, 29 parts; dried jelly of Iceland moss, 11 parts; mix.

2. (Cadet.) Chocolate, 4 lbs.; sugar, 2 lbs.; Iceland moss (freed from its bitter, and powdered), 1⁄2 lb.; tragacanth and cinnamon, of each 4 oz.; water, q. s.; to be beaten in a warm mortar, or ground with a muller on a warm slab to a paste. Recommended in pulmonary affections, general debility, weakness of stomach, &c. See Cocoa (Iceland Moss).

Chocolate, Pur′gative. Syn. Chocola′ta pur′gans, C. cathar′tica, L. Prep. 1. Jalap, 1 oz.; chocolate, 9 oz.; mix, and divide into 1-dr. cakes.—Dose, 1 to 2 cakes, as a purge.

2. Jalap, 2 oz.; calomel and sugar, of each 1 oz.; triturate together, then add chocolate, 20 oz.; for 1-dr. cakes.

3. Scammony, 2 dr.; chocolate, 3 oz.; for 1 dozen cakes. The last two are given in worms.—Dose (for an adult), 1 cake, taken fasting.

Chocolate, Sal′ep. Syn. Sal′oop chocolate; Chocola′ta cum sal′ep, L. Prep. 1. (P. C.) Chocolate, 16 oz.; powdered salep, ⁄2 oz.

2. (Cadet.) Cacao paste and sugar, of each 1 lb.; powdered salep, 1 oz. Arrowroot chocolate and tapioca chocolate are made in the same manner. (See below.)

Chocolate, Sim′ple. Syn. Hygien′ic c., Homœopath′ic c.; Chocola′ta, C. sim′plex, C. salu′tis, L.; Chocolat de santé, Fr. Prep. (P. C.) Caracas and Maragnan cocoa, of each 96 lbs.; sugar, 160 lbs.; cinnamon, 1 oz. (to 2 oz.); triturated together in the usual manner, and formed into cakes or powder.

Chocolate, Vanil′la. Syn. Chocola′ta cum vanil′la, L. Prep. 1. (P. C.) Chocolate (plain,—P. C.), 16 oz.; vanilla, ⁄2 dr.

2. (Cotterau.) Cocoa paste, 6 lbs.; sugar, 10 lbs.; vanilla, 11 dr.

See forms previously given.

Chocolate, Ver′mifuge. Syn. Chocola′ta vermifu′ga, L. See Chocolate, Purgative (Nos. 2 and 3, above).

Chocolate, White. Syn. White cocoa, Car′rageen c.; Chocola′ta cum chon′dro, Pas′ta caca′o cum chon′dro, P. c. c. lichen′e carraghen′o, L. Prep. 1. As Iceland moss chocolate, but employing carrageen moss.

2. (Ph. Dan.) Roasted and decorticated cocoa seeds (reduced to a subtile mass in a warm iron mortar) and powdered white sugar, of each 2 lbs.; powdered carrageen (debitterised), 3 oz.

3. (Cottereau.) Sugar, 6 lbs.; rice flour, 1⁄4 lb.; potato starch and butter of cocoa, of each ⁄2 lb.; gum Arabic ⁄4 lb. (dissolved); tincture of vanilla, ⁄2 fl. oz.; boiling water, q. s.; triturate to a stiff paste. The above are highly nutritious, and are recommended as articles of diet for convalescents and debilitated persons.

CHOKE-DAMP. Syn. Aft′er-damp. The term applied by miners to carbonic anhydride (carbonic acid) and other irrespirable gases and vapours evolved in mines. See Carbonic Acid, Fire Damp, Ventilation, &c.

CHOKING. Threatened choking may occur either in the gullet or swallow—or in the windpipe. If in the gullet press down the tongue with the handle of a spoon, and pass the fingers down without any hesitation, when the substance may generally be dislodged or pulled up. When it is small, and has got out of reach, it may mostly be removed by filling the mouth with liquid and swallowing it at a gulp, or by swallowing a large piece of bread. Foreign bodies thus swallowed generally pass harmlessly through the bowels.

If the choking occur in the windpipe or trachea, it is usually dislodged by the paroxysm of coughing which accompanies the act. Should it fail to be so, and a sense of suffocation ensues, accompanied with blueness of countenance and difficulty of breathing, place the patient, and follow the directions given in the article “Suspended animation,” while a medical man is immediately sent for.

Treatment for Horses or Cattle.—Remove any foreign body by hand, as directed above, or have recourse to the probang. It may perhaps be necessary to call in a veterinary surgeon, in case the above methods fail, to extract the obstruction by cutting into the gullet.

CHOLAGOGUES. Medicines which promote a flow of bile.

CHOLALIC ACID. C24H40O5. Syn. Chol′ic acid. A non-nitrogenous acid existing in bile. It is best prepared by boiling the resinous mass precipitated by ether from an alcoholic solution of ox bile with a dilute solution of potassa, for 24 to 36 hours, till the amorphous potassa salt that has separated begins to crystallise. The dark-coloured soft mass is then removed from the alkaline liquid, dissolved in water, and hydrochloric acid added. A little ether will cause the deposition of the CHOLALIC ACID from this solution in crystals. With sulphuric acid and solution of sugar it strikes a purple-violet colour; this constitutes Pettenkofer’s test for bile.

CHOLE′IC ACID. Syn. Tauro-cholalic acid. A peculiar conjugated compound of cholalic acid with a substance called taurine, which contains both nitrogen and sulphur. In combination with soda, choleic acid constitutes a principal ingredient in bile.

CHOL′ERA. This word, which, from its derivation, can be only applied correctly to a bilious affection of the stomach and bowels, has been of late years very loosely extended to a malignant disease, the most marked characteristic of which is a total suspension of the functions of the biliary organs.

Cholera, En′′glish. Syn. Com′mon cholera, Bil′ious c.; Chol′era mor′bus, L. A disease characterised by bilious vomiting and purging, accompanied by more or less pain and debility. Diarrhœa is the most common precursor of the disease, and ought to be attended to without delay, particularly if the weather be warm. Cholera most frequently occurs towards the end of the summer and early in the autumn, when the increased heat of the sun stimulates the liver to an inordinate secretion of bile, by which the whole system becomes overloaded with it. Among secondary and accidental causes are sudden changes of temperature, checked perspiration, and the use of indigestible food, and food and beverages in a state of incipient decomposition. It is usually accompanied by fever, thirst, and severe colic, and sometimes by cold sweats, extreme debility, feeble pulse, &c., under which the patient sinks in 24 hours.

Treat. In most cases this complaint is not dangerous, and yields to proper treatment in a few days. As soon after the commencement of the attack as possible, some mild aperient should be administered. Opiates may be employed, both topically and by the mouth. Jeremie’s solution is stated to be very efficacious in the diarrhœa which so generally precedes cholera. A teaspoonful or two of laudanum, rubbed over the region of the stomach and bowels, is a simple application which will generally allay the pain. 10 to 20 drops of laudanum, mixed with a table-spoonful of good brandy, or a few grains of cayenne pepper, may also be taken every hour if the pain is severe. Should the stomach reject the medicine, or the vomiting be apparently increased by drinking warm diluents, a few spoonfuls of ice-cold water, or of a mixture of lemon-juice and water, may be taken instead, until the sickness abates. Dr Copeland recommends spirit of turpentine in violent attacks, both internally and as an external application in the form of warm epithems. When the violence of the symptoms has abated, tonics and bitters (as calumba, gentian, orange-peel, &c.) may be advantageously had recourse to. Calumba, in the form of a weak infusion, conjoined, if necessary, with aromatics, is, perhaps, the most valuable agent we possess for the after-treatment of the disease. See Diarrhœa.

Cholera, Malig′nant. Syn. Asiat′ic cholera, Epidem′ic c, Blue c, Pestilen′tial c, Spasmod′ic c.; Chol′era Asiat′ica, C. asphyx′ia, C. malig′na, L. This fearful disease first became known in this country in the autumn of 1831. The attack usually begins with sickness and purging; this discharge, however, is not bilious, as in ordinary cholera, but a thin, colourless fluid, like rice-water; at the same time there is great prostration of strength, and cold, clammy sweats. In a short time dreadful cramps assail the extremities and afterwards the abdomen; the body becomes bent, the limbs twisted, the countenance cadaverous, the pulse almost imperceptible, and the eyes sunken; the patient sinks into a state of apathy, and unless a favorable change speedily takes place, soon expires from exhaustion. When there is a reaction the pulse gradually returns, the natural warmth of the body is restored, and the spasms and difficulty of breathing give way. Frequently, however, the reaction is accompanied by fever closely resembling typhus, and which often terminates fatally in from four to eight days. The symptoms of epidemic cholera are not always of this terrible character.

Treat. In giving a few of the many remedies that have been recommended for this terrible disease, we may preface the list, by urgently counselling the sufferer to lose no time in sending for a medical man, in case of being attacked by this appalling malady.

1. (American Remedy.) Equal parts of maple sugar and powdered fresh-burnt charcoal, made into a stiff paste with lard, and divided into pieces the size of a filbert.—Dose. One, occasionally, swallowed whole.

2. (Austrian Specific.) The proportions of the ingredients in the following formulæ are founded on Mr Herapath’s analysis of this celebrated preparation, and are given in the nearest available whole numbers:—

a. Sulphuric acid (sp. gr. 1·845), 20 gr.; nitric acid (sp. gr. 1·500), 12 gr,; sugar and gum, of each 15 gr.; distilled or pure soft water, q. s. to make the whole weigh exactly 1 oz.

b. Sulphuric acid, 3 dr.; nitric acid, 2 dr.; simple syrup, 6 dr.; water, q. s. to make the whole weigh exactly 10 oz. A single drop of essential oil of lemon may be added.

Doses, &c. One table-spoonful is ordered to be taken in water, on the first appearance of premonitory symptoms, followed by the free use of very cold water. In half an hour a second dose is to be taken. This (as asserted) is generally sufficient to arrest the progress of the disease. A table-spoonful is then to be added to a pint of cold water, and drunk ad libitum. In more obstinate cases it is said that 4 or 5 doses are generally required to effect a cure. When collapse sets in, double doses are ordered to be given, and to be repeated after every attack of vomiting until the sickness and cramp abate. After the vomiting abates the doses are still to be repeated until 5 or 6 doses are retained by the stomach. Should quiet sleep or drowsiness come on, it is not to be interfered with. The free use of cold water or soured water is to be allowed until perspiration sets in and the warmth of the body returns. According to the report, the use of warm liquors, wines, spirits, &c., must be carefully avoided as so much poison.

Obs. A bottle of the above remedy was handed to the late Mr Wm. Herapath by the superintendent of the Birmingham police, who had received it from the head of the Austrian police, as being in general use in Austria, under the sanction of the medical department of the government, and being found to act almost as a specific in cholera. In 1831-2 it was first tried on some criminals with perfect success, and soon afterwards with similar results on thousands of the general public. In 1849 the Austrian government ordered its use in the public establishments of the empire, since which not a single case of failure had occurred in which it had been fairly tried.

3. (Mr Buxton’s Remedy.) From dilute sulphuric acid (spirit of vitriol), 25 drops; water, 1 fl. oz. For a draught; as the last.

4. (College of Physicians and Board of Health; for Premonitory Diarrhœa.) Chalk mixture, 1 oz.; aromatic confection, 10 to 15 gr.; tincture of opium, 5 to 15 drops; to be repeated every 3 or 4 hours, or oftener, if required, until the looseness is arrested.

5. (Dr Graves’s Astringent Pills.) Acetate of lead, 20 gr.; opium, 1 gr.; conserve of roses, q. s.; for 12 pills.—Dose. One every ⁄2 hour or hour, at first; then one every two hours.

6. (Homœopathic Preventive.) Camphor, 1 dr.; rectified spirit, 6 dr.; dissolve, and preserve it in a well-corked bottle.—Dose. 2 drops on a lump of sugar, sucked as a lozenge two or three times a day.

7. (Homœopathic Remedy.) As the last, repeating the dose every 10 or 15 minutes, followed by draughts of ice-cold water, until the symptoms abate.

8. (Mr Hope’s Remedy.) (a.) Red nitrous acid, 2 dr.; peppermint water or camphor julep, 1 oz.; tincture of opium, 40 drops; mix.—Dose. One to two teaspoonfuls in a cupful of thin gruel every 3 or 4 hours.

b. Spirit of wine, 1 oz.; spirit lavender, ⁄4 oz.; oil of orizinanum, ⁄4 oz.; compound tincture benzoin, ⁄2 oz.; spirits camphor, ⁄4 oz.—Dose, 20 drops on moist sugar. To be rubbed outwardly also.

9. (Liverpool Preventive Powders.) Bicarbonate of soda, 20 gr.; ginger, 10 gr.; for a dose. One to be taken in a glass of water after breakfast and supper daily.

These powders are said to have been used with good effect among the workmen in the mining and manufacturing districts during a former visitation of cholera.

10. (Police Remedy; Mr B. Child’s Remedy.) Rectified sulphuric ether and tincture of opium, of each 30 drops; for a dose for an adult; especially during the earlier stages.

11. (Mr Ross’s Astringent Pills.) Each pill contains 1 gr. of nitrate of silver, made up with crum of bread, q. s.—Dose. One pill, to be repeated after the interval of half an hour or an hour, should the symptoms continue unabated.

12. (Russian Remedy.) Sumbul, in the form of tincture, concentrated essence, in decoction, in cold infusion, and in powder in the form of pill.—Doses. Tincture, from 20 to 60 drops; essence, from 5 to 10 or 20 drops; in a little camphor julep or plain water. The physicians of Moscow and St. Petersburg ascribe to the virtues of this drug the saving of thousands of lives during the last epidemic. See Sumbul.

13. (Dr Stevens’ Saline Powders.) Bicarbonate of soda, ⁄2 dr.; common salt, 20 gr.; chlorate of potassa, 7 gr.; for a dose.

14. (Sir M. Tierney’s Remedy.) Cajeput oil, in doses of 20 to 30 drops, every two or three hours. The oil excites the nervous system and equalises the circulation. The late Sir M. Tierney and others prescribed it frequently, it is said, with considerable success.

15. (Common Remedies of the Shops.) These generally consist of chalk mixture, with a little laudanum, and some aromatic or carminative, as cassia, cinnamon, cardamoms, nutmeg, or peppermint. In a few, some astringent, as tincture of catechu, or extract of logwood, is added.

16. (Dr Beaven’s Preventative and Remedy.) The Preventative.—Sulphite of magnesia, 2 dr.; sulphurous acid, 2 oz.; water, 2 oz.; tincture of capsicum, ⁄2 oz. Mix and dissolve, a teaspoonful night and morning.

The Remedy.—Sulphite of magnesia, 2 dr., sulphurous acid, 2 oz.; water, 2 oz.; tincture of capsicum, ⁄2 oz.; sulphate of morphia, 2 gr. Mix and dissolve; a teaspoonful every half hour until relieved.

CHOLERA MEDICINE. The expressed juice of dandelion and milfoil mixed with brandy spirit. (Dr Horn).

CHOLES′TERIN. C26CH44O.H2O. This substance is found in the bile, brain, nerves, blood, &c., and forms the principal ingredient of biliary calculi (gall-stones).

Note.—The remedies containing astringents are the most efficacious.

CHOL′IC ACID. Syn. Glyco-cholal′ic acid. A peculiar acid, existing as cholate of sodium, and associated with choleic acid in the bile. It is a conjugate compound of cholalic acid with a nitrogenised substance called glycocin.

CHON′DRIN. Gelatin obtained from cartilage. It differs from ordinary gelatin in being precipitable by acetic acid, alum, and acetate of lead.

CHOREA. [Syn. St. Vitus’s Dance.] A spasmodic disease affecting children and young persons, especially girls, between eight and sixteen years of age. It is caused by a debilitated condition of the nervous system, as well as by brain disease, scrofula, imprudent diet and worms.

The treatment recommended is the regulation of the bowels by mild purgatives. If the disease can be traced to worms, these should be removed by the proper remedies. If worms are not the cause, recourse should be had to the cold, or shower-bath. The hot hip-bath will be found serviceable in some cases. Where there is paleness of the skin any of the iron preparations will prove of great use, the bowels being kept regular. The best preparations of iron are either the tincture of the perchloride, or nitrate, or the citrate of iron and quinine. Some practitioners recommend arsenic—five drops of the solution (for an adult) twice a day after meals; others valerianate of zinc.

Treatment for the Horse and other Animals.—Similar to the above.

CHRISTOFIA is a stomachic brandy or wine made of 1500 parts white wine, 20 parts cinnamon, 10 parts cloves, 60 parts bitter almonds, digested several days; 300 parts of sugar and 500 of spirit are then added, and the whole filtered. (Hager).

CHROMACOME. For dyeing the hair black. This is said to be prepared from harmless vegetable materials, but really consists of pyrogallic acid and nitrate of silver.

Chromacome. This is a French preparation which “contains nothing injurious to health.” This hair dye consists of two fluids. The first, “Le chrômacome, teinture supérieure de William W. A. T., No. 1, Bonn,” weighing about 45 grammes, is tincture of galls. The other, No. 2, is a solution of acetate of iron with a little nitrate of silver. When grey hair is moistened first with No. 1, then with No. 2, it becomes blackish-brown or black.

CHRO′MATE. Syn. Chro′mas, L. A salt in which the hydrogen of (hypothetical) chromic acid, HCrO4, is replaced by a metal or other basic radical.

Chromates:—

Prep. The insoluble chromates, as those of barium, zinc, lead, mercury, silver, &c., may be made by mixing a soluble salt of those bases with neutral chromate of potassium. The first three are yellow; the fourth brick-red; and the fifth reddish-brown, or ruby red when crystallised. The soluble chromates may all be made by direct solution of the base in the acid, or by double decomposition. The chromates of commerce are prepared from either chrome ore or chromate of potassium.

Prop., Uses &c. The chromates are characterised by their yellow or red colour, the latter predominating when the acid is in excess; and except those with the alkaline bases, they are, for the most part, insoluble in water. Both the chromate and the bichromate of potassium are extensively used in dyeing and calico-printing. The former is employed in conjunction with sulphuric acid in the laboratory as an oxidising agent and in the manufactory for bleaching sperm oil. The bichromate of ammonium and potassium are used in photography.

They are readily recognised by the following tests:—

On boiling a chromate in hydrochloric acid mixed with alcohol, chromic acid is first set free, and then decomposed, forming a green solution of chloride of chromium. Sulphuretted hydrogen and sulphurous acid effect similar changes. With acetate of lead the chromates give a yellow precipitate; with nitrate of silver, a reddish-brown; with nitrate of mercury, a red one.

CHROME ALUM. See Alums.

CHROME GREEN. See Green Pigments.

CHROME IRON. See Iron.

CHROME RED. See Red Pigments.

CHROME YELLOW. See Lead, Chromate of.

CHROMIC ACID. See Chromic Anhydride.

CHRO′MIUM. Cr. A metal discovered in native chromate of lead by Vauquelin in 1797. It is found in the state of oxide, combined with oxide of iron, in some abundance, in the Shetland Islands, and elsewhere; as chromate of lead it constitutes a very beautiful material.

Prepared in an impure condition as a white, very infusible, hard metal, by igniting the oxide with charcoal, at a white heat, in a lime crucible.

Chromous Chloride. CrCl2. Syn. Protochloride. Prep. Ignite the chromic chloride in a current of dry hydrogen. A white, foliated mass, soluble in water (evolving much heat), and yielding a blue solution, which absorbs atmospheric oxygen with astonishing rapidity, acquiring a deep-green colour, and passing into the state of oxychloride of chromium. It is the most powerful reducing or deoxidising agent known.

Chromic Chloride. Cr2Cl6. Syn. Sesquichloride. Prep. Pass dry chlorine over a mixture of sesquioxide of chromium and charcoal, heated to redness, in a porcelain tube. The chloride collects as a sublimate, of a peach or violet colour, in the cool part of the tube.

Dissolve chromic oxide in hydrochloric acid and evaporate to dryness; the residue is chromic chloride. It forms a dark green mass, containing water, which is evolved by igniting at a temperature of 400°, turning a purplish red.

Chromium Oxides:—

Chromous Oxide. CrO. Syn. Protoxide of chromium. This oxide has not yet been obtained in a satisfactory manner, but the hydrate is prepared by the addition of potassium hydrate solution to a solution of chromous chloride or sulphate. A brownish-red powder, speedily passing to a deep foxy-red, with disengagement of hydrogen, and forming pale blue-coloured salts with the acids, which absorb oxygen with avidity, whilst the metal passes into a higher state of oxidation.

Chromic Oxide. CrO3. Syn. Sesquioxide. Prepared by igniting potassium bichromate at a red heat and well washing the residue, and as hydrate by cautiously adding equal parts of hydrochloric acid and alcohol or sugar to a boiling solution of chromate of potassa in water, in small portions at a time, until the red tint disappears, and the liquid assumes a green colour; pure ammonia, in excess, is next added, and the precipitate which subsides is collected and washed with water.

Prop., &c. The anhydrous oxide is a rich crystalline, green powder, insoluble in both water and acids; fused with borax and glass, it imparts a beautiful green colour.

The hydrate is soluble in the acids and in alkaline lyes; with the first it forms salts which have a green or purple colour. These compounds may be made by direct solution of the hydrate in the dilute acids. Chromic sulphate combines with the sulphates of potassium and ammonium, giving rise to salts (CHROME ALUMS) which crystallise in magnificent octahedrons of a deep claret colour. The finest crystals are obtained by spontaneous evaporation.

These salts of chromium are the most important, the chromous salts being seldom met with, and are best recognised by the following reactions:—Caustic alkalies precipitate the hydrate, easily soluble in excess of the precipitant. Ammonia the same, but the precipitate is nearly insoluble. The carbonates of potassium, sodium, and ammonium throw down a green precipitate of carbonate and hydrate, slightly soluble in a large excess. Sulphuretted hydrogen causes no change.—Sulphydrate of ammonium precipitates the hydrate of a bluish-green colour.

Chromic Anhydride. CrO3. Syn. Chromic acid, Anhydrous chromic acid, Chromic trioxide. Prep. By conducting gaseous fluoride of chromium into a silver or platinum vessel, the sides of which are just moistened with water, and the aperture covered with a piece of moist paper, the anhydride will be deposited under the form of red, acicular crystals, which will nearly fill the vessel. When the process is skilfully conducted, the product is of exquisite beauty and chemically pure. The fluoride referred to above is obtained from fluor spar, 3 parts; chromate of lead, 4 parts; fuming (or the strongest) sulphuric acid, 5 parts; mixed cautiously in a silver or leaden retort. A red-coloured gas is evolved, which acts rapidly on glass, forming fluosilicic acid gas, and upon water forming hydrofluoric acid and chromic anhydride. The moisture of the atmosphere is sufficient to effect the decomposition last referred to; the former substance escaping as gas, and the latter being deposited in small crystals.

It is also prepared nearly pure by adding a cold saturated solution of potassium bichromate to once and a half its bulk of pure strong sulphuric acid. As the liquor cools, the anhydrous chromic acid is deposited under the form of brilliant crimson-red prisms; the mother-liquor is then poured off, and the crystals, placed between two tiles of glass or porcelain, are submitted to strong pressure for some time, under a bell-glass or jar, when the anhydride will be found sufficiently dry. It may be deprived of a little adhering moisture by placing it over sulphuric acid for a short time in vacuo.

Commercially, it is prepared by one of the two following processes:—

To a saturated solution of chromate of potassium, 100 parts, add oil of vitriol (sp. gr. 1·845), 49 parts; and let the whole cool. This is the common process. The product contains sulphate of potassium, but this does not much interfere with its value as a bleaching agent.

From chromate of barium, decomposed by concentrated nitric acid. The anhydrous chromic acid is separated from the nitrate of barium by decantation, or, which is still better, by filtration through glass or asbestos. It is then evaporated to dryness, when the nitric acid is volatilised, and pure chromic anhydride left behind. The volatilised nitric acid may be condensed, and again used for the same purpose. The only precautions necessary to ensure the purity of the anhydrous chromic acid prepared by this plan are—to use a sufficient quantity of nitric acid and to take care that the nitric acid is sufficiently concentrated and pure.

Prop., &c. Forms ruby-red anhydrous prisms, very soluble in water, with formation of true chromic acid, and extensively manufactured for the purpose of oxidising and bleaching substances.

CHROME IRON-STONE. Syn. Chrome Iron-ore. FeO.Cr2O3. This, which is the principal ore of chromium, corresponds in composition to brown oxide of chromium and to the magnetic oxide of iron; part of the iron, however, is generally displaced by the isomorphous metal magnesium, and part of the chromium by aluminium.

Chrome iron-stone is often met with in the form of octohedral crystals. Acids fail to dissolve it, and it cannot be fused in the furnace, but when heated it absorbs oxygen from the air. This oxidation may be effected very readily if the chrome ore reduced to very fine powder be mixed with a carbonate of one of the metals of the alkalies or alkaline earths, a chromate of the base being formed.

CHRYSENE. C18H12. A hydrocarbon found by Laurent in crude anthracene. It occurs in bright yellow, glistening scales. It may be obtained colourless by heating the yellow crystals with hydriodic acid and amorphous phosphorus to 240°. It cannot be sublimed without decomposition. Chrysene is very slightly soluble in cold alcohol, ether, benzene, and glacial acetic acid. In carbon disulphide it dissolves somewhat more readily. Its melting point is from 248° to 250°, and it boils at a temperature beyond that which can be registered by the mercurial thermometer.

CHRYSOPHANIC ACID. See Rhein.

CHYLE. Syn. Lymph. This is the name given to the nutritious milky fluid generated during digestion, and absorbed from the intestines by a set of vessels called the lacteals, which carry it to the thoracic duct, whence it is immediately conveyed into the circulation.

CHYME. The pulpy mass formed by the food in its first great change, in the process of digestion.

CIDER. Syn. Cyder; Pomaceum, L. Cider is the fermented juice of the apple, and is a very ancient beverage. Pliny calls cider and perry the “wine of apples and pears.”

The attention of the cider farmer should be first directed to the culture of the apple tree. The situation most appropriate for an orchard is one on rising ground, rather dry than moist, and unexposed to sea air or high winds. The soil should be strong, but not too heavy, and should be rich in the alkaline and earthy bases, especially the phosphates. The selection of the proper varieties of the apple for grafting is also a point on which particular care should be taken. It is found that the juices of different kinds of apples vary in the quantity of saccharine matter which they contain, as well as in other particulars that influence the quality and flavour of the cider prepared from them. As a general rule, those varieties should be chosen that yield a juice rich in sugar, and contain no undue amount of acid, and which, after the period of active fermentation is past, furnishes a liquor which clarifies itself and keeps well. This quality of the juice may generally be determined from its specific gravity. The heaviest and clearest is the best, other points being equal. The specific gravity of the juice of the different varieties of apple varies from 1·060 to 1·100.

Cider apples are classed under three heads—bitter, sweet, and sour. The first are the best; their juice has the greatest specific gravity, is the richest in sugar, ferments the most freely, clarifies spontaneously the quickest, and keeps the best after fermentation. They contain a minute quantity of extractive matter which is not present in other apples. The juice of sweet apples ferments tumultuously, clears with difficulty, and the resulting cider does not keep so well as that produced from the first variety. The juice of sour apples contains less sugar and more acid than the other two, and consequently not only produces the weakest, but the worst cider; it, however, “fines” well, although it “stores” badly. Sour and “rough-tasted” apples are usually preferred by farmers for making cider. This preference, which is very decided in the West of England, may be readily accounted for. The sour and rough-tasted apples contain less sugar and more malic acid than some of the other varieties, and the presence of this acid impedes the conversion of the alcohol of the cider into vinegar; a change which their rude mode of operating renders otherwise inevitable. But cider made with such apples never equals in quality that prepared at a low temperature, from fruit abounding in sugar, provided equal skill is exercised in the manufacture as in the process of converting malt-worts into beer.

The process of making cider varies in different places, but in every case essentially consists of the collection of the fruit, the expression and fermentation of the juice, and the storing and management of the fermented liquor.

The collection of the fruit should not be commenced before it has become sufficiently mature, and should be performed with greater care than is commonly bestowed upon it. The apples, after being gathered, are usually left for 14 or 15 days in a barn or loft to mellow, during which time a considerable portion of the mucilage is decomposed, and alcohol and carbonic acid developed. If this “ripening” is allowed to go too far, loss arises, notwithstanding the vulgar prejudice in its favour. The spoiled apples are then separated from the sound ones, as they not only impart a bad flavour to the cider, but impede its spontaneous clarification.

The expression of the juice is the next step in the process of cider-making. The apples are crushed or ground in mills consisting of two fluted cylinders of hard wood or cast-iron, working against each other. The common practice is next to sprinkle the pulp with ⁄6th to ⁄4th of its weight of spring or river water, and then to allow it to remain in tubs or wooden cisterns for 12 or 14 hours, during which time incipient fermentation commences, and the breaking up of the cells of the membrane takes place, by which the subsequent separation of the juice is facilitated. This plan, though general among cider manufacturers, is prejudicial to the quality of the future liquor; as not only is a portion of the newly formed alcohol lost, but the skins and pips often impart to it a disagreeable flavour. By employing more efficient crushing machinery this system of vatting is rendered quite unnecessary. A machine furnished with a revolving circular rasp, similar to that used in making potato starch, is admirably adapted to this purpose.

The pulp of the crushed or ground apples is now placed on a kind of wicker frame, or in hair-cloth or coarse canvas bags, and after being allowed to drain into suitable tubs or receivers, is subjected to powerful pressure, gradually applied, in the cider press. The liquor which runs off first is the best, and is usually kept separately; whilst that which follows, especially the portion obtained by much pressure, tastes of the pips and skins.

The expressed juice or “must,” obtained as above, is next put into clean casks with large bung-holes, and freely exposed to the air and the shade, where they are placed on “stillions,” with flat tubs under them to catch the waste. They are now constantly attended to and kept quite full, in order that the yeast, as it forms, may froth over and be carried off from the surface of the liquor. After 2 or 3 days for weak cider, and 8 or 10 days for strong cider, or as soon as the sediment has subsided, the liquor is “racked off” into clean casks, which have been (according to the common practice) previously sulphured with a cooper’s match. The casks containing the “racked cider” are then stored in a cellar, shaded barn, or other cool place, where a low and regular temperature can be ensured, and are left to mature or ripen. By the following spring the cider is commonly fit for use, and may be “re-racked” for sale.

The marc, or pressed pulp, is generally again sprinkled with ⁄3 or ⁄2 its weight of water, and re-pressed. The resulting liquor, when fermented, forms a weak kind of cider (cider moil, water moil), which is reserved for domestic use in the same way as table-beer. The refuse-pulp (apple-marc, pomace, pommage, apple cheese) is used as food for pigs and store cattle, and is very acceptable to them.

The storing and management of cider are matters of vast importance to the cider farmer, the factor, the wholesale dealer, and the bottler. The principles by which these should be directed are precisely similar to those which are explained under the heads Brewing, Fermentation, and Malt Liquors; and which, indeed, refer, with slight modifications, to all fermented liquors.

Preparatory to bottling cider it should be examined, to see whether it is clear and sparkling. If not so, it should be clarified in a similar way to beer, and left for a fortnight. The night before it is intended to put it into bottles the bung should be taken out of the cask, and left so until the next day, and the filled bottles should not be corked down until the day after; as, if this is done at once, many of the bottles will burst by keeping. The best corks should alone be used. Champagne bottles are the variety generally chosen for cider. It is usual to wire down the corks, and to cover them with tinfoil, after the manner of champagne. A few bottles at a time may be kept in a warm place to ripen. When the cider is wanted for immediate use, or for consumption during the cooler portion of the year, a small piece of lump sugar may be put into each bottle before corking it; or, what is the same thing in effect, the bottles may be corked within 2 or 3 hours after being filled. In summer, and for long keeping, this practice is, however, inadmissible. The bottled stock should be stored in a cool cellar, when the quality will be greatly improved by age. Cider for bottling should be of good quality, sound and piquant, and at least a twelvemonth old. When out of condition it is unfit for bottling.

Qual., &c. Cider, when of good quality, and in good condition, is doubtless a very wholesome liquor. Cider consumers, living in the cider districts, appear to enjoy almost an immunity from cholera, and often from other diseases which are common in other parts of the kingdom. At the same time, however, it is right to mention, that the dry colic or belly-ache (colica pictonum) is far from uncommon in these districts, but is wholly confined to those who drink early, hard, or inferior cider, made from harsh, unripe fruit. We believe that, in most cases, it may be referred to the acid of the common cider having acted on the lead, pewter, or copper of the articles or utensils with which it has come in contact, and of which it has dissolved a very minute portion. The best cider contains from 8% to 10% of absolute alcohol; ordinary cider from 4% to 6%.

Concluding Remarks. Much of the excellence of cider depends upon the temperature at which the fermentation is conducted; a point utterly overlooked by the manufacturers of this liquor. Instead of the apple-juice, as soon as it is expressed from the fruit, being placed in a cool situation, where the temperature should not exceed 50° or 52° Fahr., it is frequently left exposed to the full heat of autumn. In this way much of the alcohol formed by the decomposition of the sugar is converted into vinegar by the absorption of atmospheric oxygen, and thus the liquor acquires that peculiar and unwholesome acidity known in the cider districts by the name of “roughness.” When, on the contrary, the fermentation is conducted at a low temperature, nearly the whole of the sugar is converted into alcohol, and this remains in the liquor, instead of undergoing the process of acetification. The acetous fermentation, by which alcohol is converted into vinegar, proceeds most rapidly at a temperature of about 90° Fahr., and at lower temperatures the action becomes gradually slower, until at 46° to 50° Fahr. no such change takes place. (Liebig.) It is therefore evident that if the saccharine juice of apples, or any other fruit, is made to undergo the vinous fermentation in a cool situation, less of the spirit resulting from the transformation of the sugar will be converted into acetic acid, and, consequently, more will be retained in an unaltered state in the liquor, to improve its quality, and by its conservative and chemical action to preserve it from future change. This is the principal cause, other circumstances being alike, of the difference in the quality of the cider made by persons living in the same district. The one has probably a cooler barn and cellar than the other to store his liquor in, and is more careful to keep the pulp and juice cool during the early part of the process. In Devonshire the pressing and fermentation are conducted in situations where the temperature varies little from that of the external air, and fluctuates with all its changes; the result is that Devonshire cider, of the best class, will rarely keep more than 4 or 5 years, and seldom improves after the second or third year; whilst the cider of Herefordshire and Worcestershire, where these operations are more carefully attended to, will keep for 20 or 30 years.

When the pressing the apples for the juice is deferred until late in the season, it sometimes happens that the fermentation is sluggish. Though the juice has been set on the old system, in November or December, the working hardly commences until March. At this time the cider is sweet; it now rapidly becomes pungent and vinous, and is soon ready to be racked for use. If the fermentation still continues, it is again racked into a clean cask that has been sulphured; or two or three cans of the cider are put into a cask, and a brimstone-match burned in it. The cask is then agitated, after which it is nearly filled with the cider. By this process the fermentation is checked, and the cider in a short time becomes fine. Great care must be taken that the sulphuring be not overdone, as it is apt to impart a slightly unpleasant flavour to the liquor. If, on the first operation, the fermentation is not checked, the process of ‘racking’ is repeated, until the liquor becomes clear, and is continued from time to time, till the cider is in a quiet state and fit for drinking.

A common practice in Devonshire is to add a stuff called ‘stum,’ sold by the wine-coopers, or an article called ‘antiferment,’ sold by the druggists, for the purpose of checking the fermentation, but a much better plan is that described above.

To improve the flavour of weak cider, or to render ordinary cider more vinous, various plans are followed by the cellarmen and bottlers. An excellent one is to add to each hogshead 1⁄2 gall. of good brandy or rum, with 2 oz. of powdered catechu (dissolved in water), 10 lbs. of good moist sugar or honey, ⁄2 oz. each of bitter almonds and cloves, and 4 oz. of mustard seed (all in powder). These must be well ‘rummaged’ into the liquor, and the whole occasionally stirred up for a fortnight, after which it must be allowed to repose for 3 or 4 months, when it will usually be found perfectly ‘bright,’ and no bad substitute for foreign wine. Should this not be the case, the liquor must be ‘fined’ with a pint of isinglass finings, or a dozen eggs, and allowed to rest for a fortnight. If the cider is preferred pale, the catechu must be omitted, and instead of isinglass, a quart of skimmed milk is to be used as ‘finings.’ When desired of a pinkish tint, 1 oz. of cochineal (in powder) may be added instead of the catechu.

About 13 cwt. of November apples commonly yield one hogshead of cider. In Devonshire about 6 sacks or 24 bushels are the common quantity for the hogshead of 63 galls.

The best cider made at the present day is that of Normandy, Herefordshire, and New Jersey (U.S.), and next that of Devonshire and Somersetshire. See Antiferment, Fermentation, &c.

Cider, Champagne. This name is given in the United States of America to a fine, pale variety of cider, much used for bottling, which has a great resemblance to inferior champagne. The best variety comes from New Jersey. The name is also applied in this country in a similar manner. The following is a good form for a ‘made’ cider of this class:—

Prep. Good pale vinous cider, 1 hhd.; proof spirit (pale), 3 galls.; honey or sugar, 14 lbs.; mix well, and let them remain together in a temperate situation for 1 month; then add orange-flower water, 3 pints; and in a few days fine it down with skimmed milk, ⁄2 gall. A similar article, bottled in champagne bottles, silvered, and labelled, is often sold to the ignorant for champagne.

Cider, Made. An article under this name is made in Devonshire, chiefly for the supply of the London market, it having been found that the ordinary cider will not stand a voyage to the metropolis without some preparation. The finest quality of ‘made’ cider is simply ordinary cider racked into clean and well-sulphured casks; but the mass of that which is sent to London is mixed with water, treacle, and alum. The cider sold in London under the name of Devonshire cider would be rejected even by the farmers’ servants in that county.

Cider, Raisin. This is made in a similar way to raisin wine, but without employing sugar, and with only 2 lbs. of raisins to the gall., or even more, of water. It is usually fit for bottling in 10 days, and in a week longer is ready for use.

CIDER SPIRIT. See Brandy.

CIGAR. Syn. Segar; Cigarre, Fr.; Cigarro, Span. A small roll of tobacco-leaf used for smoking. The leaf is stalked or stripped of its midrib, and damped before it passes into the hands of the cigar-roller. The envelope or skin is cut from a smooth, unbroken leaf, and is quickly rolled round sufficient tobacco to form the inside. To secure the loose end of the envelope a small quantity of paste, coloured brown with chicory, is generally used. Only those who have had great practice can make cigars of a good shape. A full account of the manufacture of cigars does not come within the scope of this work. Although cigars of British make cannot compete in point of flavour with those manufactured in tobacco-growing countries, they have obtained a high degree of favour from the excellent manner in which they are made, and from their comparative cheapness. For information respecting the adulteration of cigars, and the influence of their use upon health, see Tobacco.

CIGARS. (In pharmacy.) Syn. Med′icated cigars, M. cigarettes′. The administration of medicinal agents in the form of cigars is of recent introduction, and as yet in only very limited use. The medicinal substance, if of a suitable description, as the leaves of plants, is made up into small rolls, like cheroots, and then smoked in the usual manner. In some cases, common cigars, or paper cigars (cigarettes), are medicated by moistening them in a preparation of the article to be administered. When the narcotic property of the tobacco would prove injurious, it is first exhausted by soaking and washing it in water.

Cigars, Aromatic. Syn. Aromatic cigarettes; Cigarettæ aromat′icæ, L.; Cigarettes aromatiques, Fr. Aromatic spices, lavender flowers, &c., made into cigarettes. Smoked for their odour; and in tooth-ache, face-ache, &c. See Cigars, Scented.

Cigars, Arsenical. Syn. Cigarr′æ arsenicales, L. Prep. Dissolve arseniate of soda, 1 part, in water, 30 parts; dip white, unsized paper into the solution, and form it into small rolls, 3 or 4 inches long. Used in pulmonary consumption; 4 or 5 whiffs as many times a day.

Cigars, Balsamic. Syn. Balsamic cigarettes; Cigarræ balsamicæ, Cigarettæ b., L. Thick, unsized paper is soaked in a solution of saltpetre and dried; after which it is brushed over first with tincture of cascarilla, and when again nearly dry, with compound tincture of benzoin; in about half an hour it is cut into pieces (1⁄2 × 4 inches), and rolled into cigarettes. Used in hoarseness, loss of voice, asthma, &c.

Cigars, Belladonna. Syn. Belladonna cigarettes; Cigarettæ belladonnæ, L. Prep. 1. Belladonna leaves made into cigarettes of 1 dr. each.

2. (Compound—C. b. compos′itum.) From belladonna leaves, 4 parts; moistened with tincture of opium (Ph. L.), 1 part; dried and made into 1 dr. cigarettes, as before.

Used as an anodyne and antispasmodic, in troublesome coughs, hooping-cough, toothache, sore throat, tic douloureux, &c.

Cigars, Camphor (Raspail, Paris). A remedy for various chest diseases, such as catarrh, hoarseness, loss of voice, coughs, spasms, hooping-cough, phthisis; also, if the saliva be swallowed, for heartburn, pains in the stomach, and gastritis. They consist either of a straw or quill filled with broken camphor, or of a bone or horn mouthpiece, furnished at the outer end with a little capsule for the camphor. (Wittstein.)

Cigars, Cam′phor. Syn. Camphor cigarettes; Cigarett′æ campho′ræ, L.; Cigarettes de camphre, Fr. Prep. 1. Bibulous paper, moistened with 2 or 3 drops of essence of camphor, and rolled into cigarettes. For use they are loosely placed in a tubular cigar-holder.

2. (Raspail.) These are made by loosely filling a quill or large straw with small fragments of camphor, closing the open end with a little cotton wool or bibulous paper, and piercing the closed end with a pin, to allow the passage of air.

Obs. Both the above are used unlighted by drawing the air through them into the mouth, which then becomes very slightly charged with the vapour of camphor. In cold weather the vaporisation is promoted by holding the cigarette for a few minutes in the warm hand. The homœopathists regard them as prophylactic of cholera, and the common people hold them to possess the same virtue in reference to contagious diseases generally, but especially typhus and scarlet fever. They should not be employed oftener than 3 or 4 times a day.

Cigars, Hen′bane. Syn. Cigarr′æ hyoscy′ami, L. From henbane leaves, as directed under Belladonna Cigars.

Cigars, Indian Hemp. The plant is made into cigarettes, which are used in asthma. They must be used with caution.

Cigars, Mercu′′rial. Syn. Cigarr′æ mercuria′les, L. Prep. (Paul Bernard.) Ordinary cigars are deprived of their narcotic properties by soaking them in water, and are then wetted with a weak solution of corrosive sublimate, to which a little opium is generally added. The proportion may be, of corrosive sublimate, 1 gr.; rectified spirit, 20 drops; dissolve; add laudanum, 15 drops; with this solution 6 cigars are to be equally moistened to within about 1⁄2 inch of the mouth end, and then set aside to dry.

Used by persons afflicted with syphilitic affections of the throat and palate, as a convenient method of mercurial fumigation. For those accustomed to the use of tobacco, mild cigars, undeprived of their nicotine, may be employed for the purpose.

Cigars, Scent′ed. Syn. Perfu′′med cigars; Cigarr′æ aromat′icæ, L. Prep. 1. By moistening ordinary cigars with a strong tincture of cascarilla, to which a little gum benzoin and storax may be added. Some persons add a small quantity of camphor, or of oil of cloves or cassia.

2. By soaking the tobacco, of which the cigars are to be made, or the cigars themselves, for a short time in a very strong infusion of cascarilla, and then allowing them to dry by a very gentle heat.

3. By simply inserting very small shreds of cascarilla bark between the leaves of the cigar or in small slits made for the purpose.

Obs. The above yield a very agreeable odour when smoked; but are said to intoxicate quicker than unprepared cigars of equal strength and quality. They lose much of their fragrance by age.

Cigars, Stramo′′nium. Syn. Datu′ra cigars; Cigarræ stramo′′nii, L. From the leaves of Datura stramonium, or preferably those of the eastern species, Datura tatula. See Asthma, Datura.

CINCHONA BARKS. Syn. Cinchonæ cortex; Peruvian bark; Jesuit’s bark. The native names are quinquino and quina, quina. Of the nearly forty different known species of cinchona trees, the barks of about a third are employed, some either directly in medicine, but by far the larger number as sources of quinine and the other cinchona alkaloids. The original habitat of the genus Cinchona is the Andes, where it is found at a height of between 3000 and 12,000 feet above the sea, growing mostly in patches, distributed amongst the palms, plantains, and other tropical trees that form the vast forests, for the most part clothing the eastern slopes of the Cordilleras, and extending from 10° north to about 19° south latitude. In this district there is always an abundance of moisture and a mean temperature of about 62°. In 1853 the Dutch government introduced the cinchona into Java, and in 1861 the East Indian government, following their example, introduced it into British India, where it is now acclimatised, large plantations of it growing on the Neilgherries and in the valleys of the Himalayas. The cinchona is now also successfully cultivated in Ceylon and Jamaica.

The method followed in the collection of the bark by the Peruvians is a very wasteful and destructive one, and consists either in stripping the bark from the trees when they have attained a sufficient age, or in felling the tree a little above the roots. If the latter method be adopted, the roots give out a growth of suckers, which yield a good bark. The bark is never removed during the rainy season.

Previous to being stripped off, the bark is sometimes cleaned with a brush, and then peeled off in pieces varying from 15 to 18 inches long, and from 4 or 5 in width. The thinnest pieces, which are derived from the branches or the trunks of small trees, are dried in the sun, and thus acquire the well-known quill-like form. The larger trunks yield the flat specimens, which are submitted to a kind of pressure as they are being dried. The inferior specimens being rejected, the dried barks (mostly of the same kind) are sewed in canvas, and thus conveyed to the nearest depôt, from whence, previous to being shipped, they are enclosed in another envelope of fresh hide, the package being then known under the name of a seron.

Structure of Cinchona Barks. A few general observations on the structure of the bark of cinchona will be appropriate here. The epidermis is only found on the youngest bark, before it has attained sufficient age for medicinal use; it is then replaced by the corky layer. In most species this cracks, and is easily separable, but in some it is firmly attached to the internal layers. These are composed of the middle layer of the bark or mesophlæum, formed of parenchyma, and the innermost layer endophlæum, or liber. The middle layer disappears in some barks, which are thus wholly composed of liber. This is a means of distinguishing them. The liber is traversed by medullary rays, which project into the mesophlæum. It is, therefore, composed of woody fibres (prosenchyma) and soft parenchyma.

The arrangement of the woody fibres, their colour, size, and shape, give a special character to the cinchona barks.

As compared with other barks, the fibres of the liber are shorter and more loosely arranged, being for the most part separate or united into very short bundles. The fibres, therefore, are easily isolated; they are spindle-shaped, sub-quadrangular, rarely exceeding 1-10th of an inch in length, usually straight, and are very brittle, the cavity of the cell of which each is composed being reduced by secondary deposits to a fine canaliculus. This short and loose fibrous structure is not found in other barks.

In some cinchona bark a system of lactiferous vessels is found between the liber and mesophlæum.

The parenchyma of the barks abounds in starch and oxalate of lime, or else contains a soft brown deposit.

The ‘British Pharmacopœia’ divides the cinchona barks into the three classes of—

1. Yellow Cinchona Bark. Syn. Cinchonæ flavæ cortex. The Cinchona Calisaya of Weddell.

2. Pale Cinchona Bark. Syn. Cinchonæ pallidæ cortex. The bark of Cinchona officinalis; var. Condaminea of Hooker. This bark is also known under the name of Crown-bark, from its having formerly been used by the royal family of Spain.

3. Red Cinchona Bark. Syn. Cinchonæ rubræ cortex. The Cinchona succirubra of Pavon.

The therapeutic properties of the cinchona barks are due to the following alkaloids:—

Quinia, or quinine, having the composition C20H24N2O2.

Quinidia, or quinidine, having the composition C20H24N2O2.

Cinchonia, or cinchonine, having the composition C20H24N2O.

Cinchonidia, or cinchonidine, having the composition C20H24N2O.

Quinamina, or quinamine, having the composition C20H24N2O2.

Besides the above, an alkaloid, which has been named Paracina, has been obtained from the bark of the Cinchona succirubra; whilst in those barks which contain only small portions of the more active constituents above named there have been found two alkaloids, named respectively Aricia and Cusconia, which have lately been accurately investigated by Hesse, who has determined their chemical constitution (Liebig’s ‘Annalen und Berichte der Chemische Gesselschaft in Berlin’).

The following Prospectus of the principal Species of Cinchona is from Flückiger and Hanbury’s ‘Pharmacographia,’

Species (excluding Sub-species and Varieties) according to Weddell. Where figured. Native Country. Where cultivated. Product - Cinchona Barks.

I. Stirps Cinchonæ officinalis—

1. Cinchona officinalis, Hook. ‘Bot. Mag.,’ 5364 Ecuador Loxe, Peru India, Ceylon, Java Loxa, or Crown Bark, Pale Bark.

2. Cinchona macrocalyx, Pav. Howard, ‘N. Q.’ Peru — Ashy Crown Bark. The sub-speciesC. Palton affords an important sort called Palton Bark, much used in the manufacture of quinine.

3. Cinchona lucumæfolia, Pav. Howard, ‘N. Q.’ Ecuador, Peru — Carthagena Bark, confounded with Palton Bark, but is not so good.

4. Cinchona lanciolata, R. and P. Howard, ‘N. Q.’ Peru — Columbian Bark. Imported in immense quantities for manufacture of quinine. The soft Columbian Bark is produced by Howard’s var. oblonga.

5. Cinchona lancifolia, Mutis. Karst., tab. 11, 12 New Granada India Ditto.

6. Cinchona amygdalifolia, Wedd. Wedd., tab. 6 Peru, Bolivia — A poor bark, not now imported.

II. Stirps Cinchonæ Rugosæ—

7. Cinchona Pityrensis, Wedd. Karst., tab. 22 (G). Triane New Grenada, Popayan India Pitayo Bark. Very valuable; used by makers of quinine. It is the chief source of quinidine.

8. Cinchona rugosa, Pav. Howard, ‘N. Q.’ Peru — Bark unknown, probably valueless.

9. Cinchona Mutisii, Lamb. Howard, ‘N. Q.’ Ecuador — Bark, not in commerce, contains only aricine.

10. Cinchona hirsuta, R. and P. Wedd., tab. 21 Peru —

11. Cinchona Carabayensis, Wedd. Wedd., tab. 19 Peru, Bolivia — Bark, not collected.

12. Cinchona panudiana, How. Howard, ‘N. Q.’ Peru India, Java A poor bark, yet of handsome appearance; propagation of tree discontinued.

13. Cinchona asperfolia, Wedd. Wedd., tab. 20 Bolivia — Bark not collected.

14. Cinchona umbelluliferæ, Pav. Howard, ‘N. Q.’ Peru — Bark not known as a distinct sort.

15. Cinchona glandulifera, R. and P. Howard, ‘N. Q.’ Peru — Bark not known as a distinct sort.

16. Cinchona Humboldtiana, Lamb. Howard, ‘N. Q.’ Peru — False Loxa Bark, Jaen Bark. A very bad bark.

III. Stirps Cinchonæ Micranthæ—

17. Cinchona Australis, Wedd. Wedd., tab. 8 South Bolivia — An inferior bark, mixed with Calisaya.

18. Cinchona scrobiculata, H. and B. Wedd., tab. 8 Peru — Bark formerly known as Red Cusco Bark or Santa Anna Bark.

19. Cinchona Peruviana, How. Howard, ‘N. Q.’ Peru India

20. Cinchona nitida, R. and P. Howard, ‘N. Q.’ Peru India Grey Bark, Huanuco, or Lima Bark.

21. Cinchona micrantha, R. and P. Howard, ‘N. Q.’ Peru India Chiefly consumed on the Continent.

IV. Stirps Cinchonæ Calisayæ—

22. Cinchona Calisaya, Wedd. Wedd., tab. 9 Peru, Bolivia India, Ceylon, Java, Jamaica, Mexico Calisaya Bark, Bolivian Bark, Yellow Bark. The tree exists under many varieties; bark also very variable.

23. Cinchona elliptica, Wedd., tab. 9 Peru, Carabaya — Carabaya Bark. Bark scarcely now imported. C. cuneura, Miq. (flower and fruit unknown), may perhaps be this species.

V. Stirps Cinchonæ ovatæ—

24. Cinchona purpurea, R. and P. Howard, ‘N. Q.’ Peru, Huamalies — Huamalies Bark, not now imported.

25. Cinchona rufinervis, Wedd. Howard, ‘N. Q.’ Peru, Bolivia — Bark a kind of light Calisaya.

26. Cinchona succirubra, Pav. — Ecuador India, Ceylon, Java, Jamaica Red Bark; largely cultivated in British India.

27. Cinchona ovata, R. and P. Howard, ‘N. Q.’ Peru, Bolivia India (?), Java (?). Inferior brown and grey barks.

28. Cinchona cordifolia, Mutis. Karst., tab. 8 New Granada, Peru — Columbian Bark (in part). Tree exists under many varieties; bark of some used in manufacture of quinine.

29. Cinchona Tucujensis, Karst. Karst., tab. 9 Venezuela — Maracaibo Bark.

30. Cinchona pubescens, Vahl. Wedd., tab. 16 Ecuador, Peru, Bolivia — Areca Bark (Cusco Bark from var. Pelletieriana). Some of the varieties contain aricine. C. caloptera, Miq., is probably a variety of the species.

31. Cinchona purpurascens, Wedd. Wedd., tab. 18 Bolivia — Bark unknown in commerce.

The cinchona barks vary greatly in the amount of alkaloids they contain and in their proportion to each other, these being dependent upon the species or varieties, and many other circumstances. Of the alkaloids, quinia and cinchonia were till lately the most abundant, but since the introduction of cinchona cultivation into India, cinchonidia has been found in very large quantity. Royle says:—“Good Calisaya bark usually contains from 5 to 6 per cent. of quinia,” but actually South American calisaya containing such an amount of quinia is rare in the market. Some barks, however, derived from cinchonas cultivated in India, such as C. Calisaya, var. Ledgeriana, and some varieties of C. officinalis, yield even a still higher per-centage of quinine.

The South American crown, or loxa bark, is very variable, and contains chiefly cinchonia.

Red bark also varies considerably, yielding from 3 to 10 per cent. of alkaloids, of which quinia forms only a small fraction, whilst generally cinchonidia is predominant. The development of the alkaloids is greatly influenced by cultivation, but particularly by the “renewing process,” which, applied to the C. succirubra, trebles the amount of quinine in the bark.

In addition to the alkaloids already mentioned, the cinchona barks contain the following acid principles:—Kinic acid, Cincho-tannic acid, and Quinovic or Chinovic acid. The quinovic acid is accompanied by an amorphous bitter substance, named Chinovin or Quinovia, which is present in much greater proportion than the acid, of which generally there are only traces. A description of these bodies will be found by referring to them under their respective names. Cinchona-red is another amorphous substance which is the body to which the red hue of the cinchona barks is due. It is produced when cincho-tannic acid is boiled with dilute sulphuric acid, sugar being formed at the same time.

When fused with potash, proto-catechinic acid is formed. Cinchona red dissolves sparingly in alcohol, freely in alkaline solutions, but neither in water nor ether. Thick red bark contains it to the amount of more than 10 per cent.

Cinchona red is the product of the oxidation of cincho-tannic acid, and is contained largely in South American red bark, because this is the product of old trees; but sparingly in Indian red bark, because this is always collected from trees not more than fourteen years old.

Medicinal Properties of the Cinchona Barks. The therapeutic effects of the cinchona barks are doubtless due to the alkaloids they contain; but spite of their variability of composition in this respect, which has been shown to be very great, they are very extensively employed in medical practice in the forms of powder, decoction, tincture, and extract.

Dr de Vrij, the eminent quinologist, is of opinion that the therapeutic effects of bark are chiefly due in part to the alkaloids, and in part to the cincho-tannic acid they contain; and as red Indian bark is rich in both these constituents, he considers it the best suited for medical practice. See Quinetum.

Garrod says:—“Given in small doses, bark causes an increase of appetite, especially in weak patients, and at the same time improves the condition of the muscular system; hence the improvement of the blood and general health. It may, therefore, be well designated a tonic.

Its power in bracing up the system is also seen in the check given to the colliquative sweating occurring in extreme debility. The pulse is not quickened by the use even of large doses of quinine, although it is frequently made stronger, nor does bark itself, in the majority of cases, increase the heart’s action.

Bark also produces a peculiar influence upon the nervous system, which is exhibited in the extraordinary power it possesses of arresting the progress of certain diseases characterised by a periodical recurrence of their symptoms, as ague, the different forms of neuralgia, and certain inflammatory affections; how this effect is produced is at present unknown. Bark acts likewise as an astringent, and this property, combined with the tonic and antiperiodic powers, is often of much therapeutic value.”

For the method of estimating the alkaloids in cinchona bark, see Quinometry, Quinine, Quinidine, Quinoidine, Quinicone, Quinamine, Cinchonine; also the different pharmaceutical preparations of Cinchona bark.

CINCHONIDINE. Syn. Cinchonidia. C20H24N20. This cinchona alkaloid is isomeric with cinchonine. It occurs in large, shining striated, rhombic prisms, which are anhydrous. It dissolves in ·76 parts of ether and 20 of spirit of wine. The solutions are fluorescent, but do not answer to the chlorine and ammonia tests.

“The great powers and activity of this alkaloid have only of late been appreciated. As a protoplasm-poison, and probably in every other physiological action, it comes next to quinine and quinidine, and decidedly above cinchonine.”

If it is chemically pure, cinchonidine belongs to the non-fluorescent alkaloids.

CINCHONINE. Syn. Cinchonia. C20H24N2O. This alkaloid abounds most in the paler varieties of the cinchona barks. It occurs in clear, colourless, four-sided prisms, which are soluble in 30 parts of water, and in about 400 parts of ether and 120 of spirits of wine. With acids it forms soluble salts, which do not fluoresce in solution, and are turned lightish brown-yellow by the chlorine and ammonia tests. Of its salts, the hydriodate is readily soluble in water, and still more so in alcohol, whether dilute or strong. Cinchonine may be prepared from its sulphate or disulphate in the same way as quinine.

Cinchonine, Sulphate of. Syn. Cinchoniæ sulphas. (Ph. U. S.) Take of the mother-water remaining after the crystallisation of sulphate of quinia in the process for preparing that salt a convenient quantity, solution of soda, alcohol, diluted sulphuric acid, animal charcoal in fine powder, each a sufficient quantity. To the mother-water add gradually with constant stirring solution of soda, until the liquid becomes alkaline. Collect on a filter the precipitate formed, wash it with water, and dry it. Then wash it with successive small portions of alcohol to remove other alkaloids which may be present, mix the residue with 8 times its weight of water, and having heated the mixture, add gradually diluted sulphuric acid until it is neutralised and becomes clear. Then boil the liquid with animal charcoal, filter it while hot, and set it aside to crystallise. Lastly, drain the crystals and dry them on bibulous paper. By evaporating the mother-liquid more crystals may be obtained.

CINCHO-TANNIC ACID. This acid is precipitated from a decoction of bark by acetate of lead, after the decoction has been freed from cinchona red by means of magnesia.

If the cincho-tannate of lead thus formed be decomposed by sulphuretted hydrogen, and the solution carefully evaporated in vacuo, the acid may be obtained as an amorphous, hygroscopic substance, readily soluble in water. A ferric salt added to a solution of this acid imparts a greenish colour to it.

Cincho-tannic acid is very soluble in water, but not in acids. Therefore a concentrated watery infusion (1 to 4) of Indian bark gives a precipitate upon the addition of strong hydrochloric acid. By this means a rough estimation may be formed of the amount of cincho-tannic acid in a sample of bark.

CINCHOVATINE. The substance known under this name does not exist as an alkaloid, sui generis. It is nothing more than quinidine, or cinchonidine, or a mixture of both.

CINNABAR. Syn. Native Vermillion. This compound, which is one of the most abundant of the ores of mercury, is a product of considerable importance in the arts, and some portions of it are sometimes sufficiently pure in colour to be used after mere levigation. Generally, however, the factitious kind is employed. See Vermilion.

CINNAMEIN. C16H14O2. Syn. Oil of balsam of Peru. A volatile oil existing in balsam of Peru.

CINNAMIC ACID. HC9H7O2. A colourless, transparent, crystalline substance, obtained from oil of cinnamon, liquid storax, balsam of Peru, and balsam of tolu. It is freely dissolved by alcohol, but nearly insoluble in water. At 248° Fahr. it fuses, and at 560° Fahr. it sublimes unchanged. Distilled with dichromate of potassium and sulphuric acid it is converted into benzoic acid. Its salts are called cinnamates.

CINNAMON. Syn. Cinnamon Bark; Cinnamomi cortex (B. P.), L. The inner bark of shoots from the truncated stock of the Cinnamomum Zeylanicum, imported from Ceylon, and distinguished in commerce as Ceylon cinnamon. The best is obtained from branches about three years old.

Used in medicine as a carminative and astringent, chiefly as an adjuvant to other medicines, e.g. with chalk, in diarrhœa.—Dose, 10 to 20 grains.

Obs. Owing to the high price of this drug it has become a general practice to substitute the bark of cassia (Cassia; Cortex cinnamomi cassia) for it, which so closely resembles it in flavour that the uninitiated regard them as the same. Cassia, however, is not only thicker and coarser than cinnamon, but its fracture is short and resinous, and its flavour is more biting and hot, whilst it lacks the peculiar sweetish taste of cinnamon. The thickness of cinnamon seldom exceeds that of good drawing paper.

CISTERNS. See Tanks.

CITRATE. A salt in which the hydrogen of citric acid is replaced by a metal or other basic radical.

CIT′RIC ACID. H3C6H5O7,H2O. Syn. Acid of lemons, Concrete a. of l.; Ac′idum limo′nis, Acidum cit′ricum (B. P.), L.; Acide citrique, Fr.; Citronensaüre, Ger. An acid peculiar to the vegetable kingdom. It is obtained in large quantity from the juice of lemons and other fruits of the genus Citrus; it is also found in gooseberries, currants, cranberries, whortleberries, cherries, &c.; and Dr Wright has lately found it in great abundance in unripe mulberries, in conjunction with malic acid.

When currants or gooseberries are employed as a source of citric acid, they are first subjected to pressure, and the juice so obtained from them is then fermented. The fermented liquor is next submitted to distillation, and the alcohol collected.

The residue in the retort containing the citric acid is saturated with chalk, and the resulting citrate of lime is decomposed by means of sulphuric acid.

100 lbs. of the fruit are said to yield 10 lbs. of spirit and 1 lb. of acid.

Prep. The citric acid manufacture consists in separating it from the mucilage, sugar, and other foreign matter with which it is combined in the juice of lemons and limes.

1. (Ph. L. 1836,—Scheele’s process.) Take of lemon juice 4 pints; prepared chalk, 4⁄2 oz.; diluted sulphuric acid, 27⁄2 fl. oz.; distilled water, 2 pints. Add the chalk by degrees to the lemon juice, made hot, and mix well; set by, that the powder may subside, and afterwards pour off the supernatant liquor. Wash the precipitated citrate of lime frequently with warm water; then pour upon it the diluted sulphuric acid, mixed with the distilled water, and boil the whole for 15 minutes in glass, stoneware, or lead; press the mixture strongly through a linen cloth, and filter it. Evaporate the filtered liquor with a gentle heat, and set it aside, that crystals may form. To obtain the crystals pure, dissolve them in water a second and a third time; filter each solution, evaporate, and set it apart to crystallise.

2. (Ph. L. 1851.) Merely placed in the materia medica.

3. (Ph. E. 1841.) Similar to that of Ph. L. 1836, except that the washed citrate of lime is ordered to be squeezed in a powerful press, and that the filtered solution of citric acid is ordered to be tested with nitrate of baryta, and if the precipitate is not nearly all soluble in nitric acid, to add a little citrate of lime to the whole liquor, till it stands this test.

4. (Ph. D. 1826.) Same as that of Ph. L. 1836.

5. (Ph. D. 1851.) Included in the materia medica.

6. (P. B. 1867.) Differs from the process of the Ph. L. 1836 in some unimportant detail only.

7. (Dr Price.) The crude juice is saturated with ammonia, potassa, or soda (carbonates), or with the ammoniacal product distilled from gas-liquor; chalk, 150 parts, or hydrate of lime, 90 parts, are then added for every 192 parts of citric acid contained in the liquor, and the whole stirred well together; heat is next applied, and the ammonia distilled into another quantity of lemon juice; the citrate of lime thus obtained is then decomposed with dilute sulphuric acid, and the whole process conducted as before. When potassa or soda is used the distillation is omitted, and the expressed liquor, after filtration, used to decompose fresh lemon juice.

8. (Ordinary manufacturing process.) To crude lemon or lime juice, mixed with water, is added ground chalk; the precipitate is washed to free it from the impurities dissolved in the water, and afterwards decomposed by sulphuric acid. If the citric acid is not sufficiently white, it is decolorised by digestion with animal black.

9. (Kuhlman.) This chemist proposes saturating the hot lemon juice as far as possible with very finely divided barium carbonate, and afterwards completing the neutralisation with barium hydrate or sulphide. The precipitated barium citrate is then to be washed, and decomposed with the requisite quantity of sulphuric acid. The advantage of barium over lime as a precipitant is the more ready crystallisability of the citric acid from the solution thus obtained. Sulphate of baryta is absolutely insoluble in solution of citric acid, whilst sulphate of lime is not; and the presence of the latter impedes the crystallisation of the acid.

Obs. If the lemon or lime juice be allowed to ferment a short time, the mucilage and other impurities will, to a certain extent, separate and subside. See Concluding Remarks.

Prop., Uses, &c. Citric acid forms rhomboidal prisms, which are clear, colourless, odourless, sour, and deliquescent in a moist atmosphere. It is an agreeable acid, at once cooling and antiseptic. It is much used in medicine as a substitute for lemon juice, and to form effervescing draughts, citrates, &c.

17 gr. citric acid, in crystals, or

2

fl. oz. of lemon juice, are equivalent to—

25 gr. bicarbonate of potash;

20 ” carbonate of potash;

15 ” carbonate of ammonia;

20 ” bicarbonate of soda;

35 ” carbonate of soda.

The bicarbonate of potassa is that generally preferred for making saline draughts with citric acid; and when flavoured with a little tincture of orange peel and simple syrup, or syrup of orange peel alone, it forms a most delicious effervescing beverage. Citric acid in pure crystals or in lime juice is much used by the calico-printer, being the best known ‘resistant’ for iron and alumina mordants.

Pur. Citric acid is frequently met with adulterated with tartaric acid; the fraud is easily detected by dissolving the acid in a little cold water, and adding to the solution a small quantity of acetate of potash. If tartaric acid be present, a white, crystalline precipitate of cream of tartar will be produced on agitation. When pure it is devoid of colour, is entirely, or almost entirely, decomposed by heat. It is soluble in water and in spirit, and what is thrown down from its watery solution by acetate of lead is dissolved by nitric acid. No salt of potassium precipitates anything with citric acid except the tartrate. When a few drops of a solution of citric acid are added to lime water, a clear liquid results, which, when heated, deposits a white powder, soluble in acids without effervescence. By the action of nitric acid citric acid is converted into oxalic acid.

When the crystals of citric acid are very deliquescent, the presence of free sulphuric acid may be suspected. This latter may be detected with facility by dissolving the citric acid in a little water, strongly acidifying the solution with hydrochloric acid, and adding chloride of barium, when, if sulphuric acid be present, an insoluble precipitate of sulphate of barium will fall down after a short time. Oxalic acid is sometimes present in citric acid, the cause of its presence being explained further on. To test for it proceed as follows:

Dissolve a small quantity of the citric acid in water, and add to the solution an excess of ammonia; acidify with acetic acid, filter, and test the filtrate with calcium sulphate.

Estim. See Acidimetry and Lime juice.

Tests. See above.

Concluding Remarks. The preparation of citric acid has now become an important branch of chemical manufacture, from the large consumption of this article in various operations in the arts. In conducting the different steps of the process some little expertness and care are, however, necessary to ensure success. The chalk employed, which should be dry, and in fine powder, is added to the juice from a weighed sample, until the latter is perfectly neutralised, and the quantity consumed is exactly noted. The precipitated citrate of lime is next thoroughly washed with water, and the sulphuric acid, diluted with 6 or 8 times its weight of water, whilst still warm, is poured upon it, and thoroughly mixed with it. The agitation is occasionally renewed for 8 or 10 hours or longer, when the solution of citric acid is poured off, and the residuum of sulphate of lime thoroughly washed with warm water, the washings being added to the liquid acid. This last is then poured off from the impurities that may have been deposited, and evaporated in a leaden boiler, over the naked fire, or by high-pressure steam, until it acquires the gravity of 1·13, when the process is continued, at a lower temperature, until a syrupy aspect is assumed, and a pellicle appears on the surface of the liquor. Without great care at this part of the process the whole batch may be carbonised and spoiled. At this point the concentrated solution is emptied into warm and clean crystallising vessels, set in a dry apartment, where the thermometer does not fall below temperate. At the end of 4 days the crystals are found ready for removal from the pans. They are thoroughly drained, redissolved in as little water as possible, and after being allowed to stand for a few hours to deposit impurities, again evaporated and crystallised.

The acid of the second crystallisation is usually sufficiently pure for the market; when this is not the case a third, or even a fourth, crystallisation must be had recourse to. The mother-liquors from the several pans are now collected together, and a second or third crop of crystals obtained from them, by evaporation as before.

A frequent cause of difficulty in obtaining crystals from the solutions is the employment of too little sulphuric acid to decompose the whole of the citrate of lime; the consequence of which is that a little of that salt is taken up by the free citric acid, and materially obstructs the crystallisation. Forty parts of dry sulphuric acid are required to decompose 50 parts of chalk. Commercial sulphuric acid (oil of vitriol) is usually of the sp. gr. of 1·845, and it therefore requires 49 lbs. of this acid for every 50 lbs. of chalk employed in the process. In practice it is found that a very slight excess of sulphuric acid is preferable to a preponderance of undecomposed citrate of lime.

The first crop of crystals is called ‘brown citric acid,’ and is chiefly sold to the calico-printers. Sometimes a little nitric acid is added to the solution of the coloured crystals, for the purpose of bleaching them, but in this way a minute quantity of oxalic acid is formed. A more general plan is to bleach the citrate of lime by covering it with a weak solution of chloride of lime, exposing it in shallow vessels to the sun’s rays, and rewashing it before decomposing it with sulphuric acid. A safer plan is to dissolve the crude citric acid, digest with animal charcoal, and again concentrate the solution to the crystallising point.

When the aqueous solution of citric acid obtained, as already described, is concentrated by boiling in an open evaporating pan, the acid is not only liable to suffer partial decomposition by its long exposure to the air, but it not unfrequently acquires a brown colour from the carbonisation those portions of the liquid undergo which are in contact with the bottom of the pan, which being heated by high-pressure steam frequently reaches a temperature exceeding 200° F. This latter result is brought about in consequence of the slight movement in the dense acid liquor in the pan. To remedy the loss and inconvenience arising from the employment of the open evaporating pan, some years back Mr Pontifex devised an apparatus which effects the evaporation of acid liquor in vacuo (and therefore out of contact with air), and at a temperature never exceeding 130 F°. Moreover, in Mr Pontifex’s boiler the time necessary for the concentration of the citric-acid liquor is diminished to about an eighth, and as the strong ebullition keeps the liquid in constant motion its charring is entirely prevented.

Mr Row says that lemon juice may be purified to a great extent by diluting it with water until it contains about 12 oz. of acid to the gallon, and then filtering from the flocculent precipitate of mucilage thus thrown down. The citrate of lime obtained from juice so treated is comparatively pure.

Good lemon juice yields about 6⁄2% of crystallised lemon acid; 2 galls. yield fully 1 lb. of crystals. See Lemon juice, Lime juice. &c.

CIT′RON. The fruit of the citron tree (Citrus medica) is acidulous, antiseptic, and antiscorbutic; it excites the appetite, and stops vomiting; and, like lemon juice, has been greatly extolled in chronic rheumatism, gout, and scurvy. Mixed with cordials, it is used as an antidote to the manchineel poison.

Citron, Oil of. See Oil.

Citron Peel. This is prepared in the same way as candied orange and lemon peel, which it for the most part resembles.

Citron. Syn. Lem′on colour. The term applied to a pale and delicate shade of yellow. See Yellow Dyes, &c.

CIT′RONELLE. See Liqueurs and Oils (Lemon-grass).

CITRUS. A genus of plants belonging to the natural order Aurantiaceæ, the species of which yields useful fruits. From Citrus Aurantium, and its varieties, all the various descriptions of sweet oranges are obtained. The species C. Bigaradia or vulgaris yields the bitter or Seville orange; C. Limonum and its varieties, yield the lemons; C. Limetta is the source of the lime; C. medica of the citron; C. Decumana of the shaddock; C. paradisi of the forbidden fruit; C. Pampelmos of the Pampelmoose; and C. japonica of the kumquat.

Citrus Bergamia. (Ind. Ph.) Syn. The Lime tree. Habitat. Commonly cultivated in India and other tropical countries.—Officinal part. The fruit (lime) closely resembles the lemon, but is smaller, with a smoother, thinner rind, and of somewhat less fragrant odour. Its juice (lime juice) has the same pungent acid taste, and contains the same ingredients as lemon juice, though in somewhat different proportions, that of the citric acid being larger and that of the mucilage less in quantity. Much of the article imported into England under the name of lemon juice is obtained from the lime.—Properties and Uses. Very similar to those of the lemon, the juice being equally refrigerant and antiscorbutic; indeed, it is preferred by many tropical practitioners.

The fresh juice of the lime is procurable in almost every portion of the tropics, and is considered more effectual than preserved lemon juice.

Lime juice may be advantageously employed in the manufacture of citric acid, the proportion of this acid being larger than in lemon juice.

CIV′ET. Syn. Civet′ta Zybeth′um, L. A perfume obtained from the civet cat (Viverra civella, Linn.), a fierce, carnivorous quadruped, somewhat resembling a fox, found in China and the East and West Indies. The civet is secreted in a sort of pouch between the anus and the sexual organs. “Several of these animals have been brought into Holland, and afford a considerable branch of commerce, especially at Amsterdam. The civet is squeezed out in summer every other day, in winter twice a week; the quantity procured at once is from 2 scruples to 1 drachm or more.”

Civet is frequently adulterated with spermaceti and butter, and a similar substance to civet, but of a darker colour, obtained from the polecat. When pure it has an odour intermediate between that of musk and ambergris, but less refined; a pale-yellow colour; an acrid taste; and the consistence of honey. It is used in perfumery.

CLAIRET. See Liqueur.

CLAR′ET RAGS. Syn. Tournesol en drapeau, Fr.; Bezet′ta cœru′lea, L. 1. Pieces of clean linen coloured with Auvergne—or ground archil.

2. Pieces of linen dipped into the juice of mulberries, blood-red grapes, lees of red wine, &c. Used to colour jellies, confectionery, the rind of cheeses, &c.

CLARIFICATION. The act of clearing or making bright; commonly applied to the process of ‘clearing’ or ‘fining’ the liquids by chemical means, instead of by filtration. The substances used for this purpose are popularly known as ‘clarifiers’ or ‘finings.’

The substances employed in the clarification of liquids operate by either mechanically embracing the feculous matter, and subsiding with it to the bottom of the vessel, or by inducing such a change in its nature or bulk that it subsides by its own density, in each case leaving the liquor transparent. Albumen, gelatin, the acids, certain salts, blood, lime, plaster of Paris, alum, heat, alcohol, &c., serve in many cases for this purpose. The first is used, under the form of white of egg, for the clarification of syrups, as it combines with the liquid when cold, but on the application of heat rapidly coagulates and rises to the surface, carrying the impurities with it, forming a scum which is easily removed with a skimmer. It is also much used for fining wines and liqueurs, particularly the red wines and more limpid cordials. Gelatin, under the form of isinglass, dissolved in water or weak vinegar, is used to fine white wines, beer, cider, and similar liquors that contain a sufficient quantity of either spirit or astringency (tannin), to induce its precipitation. Sulphuric acid is frequently added to weak liquors for a similar purpose, either alone or after the addition of white of egg or gelatin, both of which it rapidly throws down in an insoluble form. A pernicious practice exists among some unprincipled manufacturers of using certain salts of lead and potash to clear their liquors; especially those that are expected to sparkle in the glass, as ‘cordial gin,’ &c. For this purpose a little sugar of lead, dissolved in water, is first mixed up with the fluid, and afterwards a little more than half its weight of sulphate of potassa, also dissolved in water, is added, and the liquor is again ‘roused’ up. By standing, the sulphate of lead, formed by this mixture, subsides, and leaves the liquor clear. Bullock’s blood is used in the same way as isinglass or white of eggs, for fining red wines, beer, and porter. Lime, alum, alcohol, acids, and heat, act by curdling or coagulating the feculencies, and thus, by increasing their density, induce their subsidence. Plaster of Paris acts, partly like the above, and partly like albumen, or gelatin, by developing and forcing down the suspended matter. Sand is often sifted over liquors (especially cordials and syrups), for the simple purpose of acting by its gravity, but appears to be quite useless, as it sinks too rapidly. The juices of plants are clarified by heat, which coagulates the albumen they contain. Marl or clay is frequently used to clear cider and perry. A strip of isinglass is generally employed to clarify coffee. See Wine, Brewing, Cordials, Coffee, Finings, Infusion, &c.

CLAY. Clay is formed from the disintegration of felspathic rocks, by the combined action of air and water. Its plasticity, when moist, and its capability of being made hard by heat, are properties which render it available for many useful purposes. The purest kind of clay is kaolin, or China clay, which consists almost entirely of silicate of aluminum. It is found in China; but a precisely similar substance is obtained from deposits in Cornwall and some parts of France. Pipe-clay, a white clay nearly free from iron, is found in large quantity in the island of Purbeck. Potter’s clay is found in many parts of Britain; that of Devonshire and Dorsetshire is much valued. Brick clay contains varying proportions of iron; hence the different colours of the bricks used in different countries. See Aluminum, Fuller’s earth, Ochre, &c.

CLEAN′ING. In domestic economy the best way to clean a house is to keep it clean by a daily attention to small things, and not allow it to get into such a state of dirtiness and disorder as to require great and periodical cleanings. Some mistresses, and also some servants, seem to have an idea that a house should undergo regular cleanings, or great washing and scrubbing matches, once every three or six months, on which occasions the house is turned almost inside out, and made most uncomfortable. All this is bad economy, and indicates general slovenliness of habits. (Chambers.) For hints upon cleaning, see Carpets, Clothes, &c.

CLEAN′LINESS. See Ablution, Bathing, and Sickness.

CLIPPING (Horses). Some horses should be worked in autumn in cloths, or with their coats on, as, on account of the extra sweating thus caused, they will be in better condition for the hunting season. Such horses should be clipped or shaved. The horse’s coat should be fully set before it is clipped. Those horses which sweat much in autumn should be singed. Singeing cannot be begun too early. The fresh growth must be removed every week. Singeing may be best accomplished by means of gas.

CLOTHES. Economy and cleanliness require due attention to be paid to every article of clothing, but more especially to those which are the most exposed to dirt and the weather. The following remarks, having reference chiefly to woollen articles, may prove useful to the reader:—If very dusty, hang them on a horse or line, and gently beat them with a cane; then lay them on a clean board or table and well brush them, first with a stiff brush, to remove the spots of mud and the coarsest of the dirt, and next with a softer one, to remove the dust and to lay the nap properly. If clothes are wet and spotted with dirt, dry them before brushing them, and then rub out spots with the hands. The hard brush should be used as little as possible, and then with a light hand, as it will, if roughly and constantly employed, soon render the cloth threadbare. Spots of tallow-grease on the clothes may be taken off with the nail, or, if that cannot be done, have a hot iron with some thick brown paper, lay the paper on the part where the grease is, then put the iron upon the spot; if the grease comes through the paper put on another piece, till it ceases to soil it. Moths may be prevented attacking clothes by putting a few cloves or allspice into the box or closet with them. See Balls, Clothes, and Scouring, &c.

CLO′′THING. In our changeable climate great care should be taken to clothe the body effectually; for when the skin is chilled the blood is determined in increased and injurious quantity to the internal organs, causing colds and inflammations. The ordinary materials for clothing are cotton, linen, woollen, and silk. Cotton is generally employed for undergarments, for which its softness and warmth render it well adapted. Linen is not nearly so warm, but it keeps its colour better; it is more expensive, and although it wears much longer, it is not so economical as cotton. Woollen garments are, in cold and variable climates, almost essential to comfort; the warmth obtained by wearing flannel next the body is very beneficial, and the slight stimulating effect arising from its roughness tends to keep the skin in healthy action.

The practice of dressing infants in long clothes is a very objectionable one, for besides being injurious to health it cramps the action of the legs, the feet, and the toes, and by so doing prevents their proper and healthy development.

An infant should be so clothed as to combine sufficient warmth with perfect freedom of the limbs; hence his garments should be loose instead of tight, more particularly round his waist.

In the selection of winter clothes for children, if for in-door wear, choice should be made of a dark woollen frock, and of stockings in preference to socks. The stockings should be of merino, and made to draw above the knees and fastened to the dress with a loop and tape instead of garters, which are very objectionable.

A child’s out-of-door attire in winter should additionally comprise a warm and properly-lined coat, made of cloth or some woollen fabric. It should button close to the chin and cover his neck. Mr Chavasse says, for this latter purpose a woollen neckerchief or scarf is preferable to furs. It is very important that the child’s feet and legs should be kept warm, but not too warm. In infancy and childhood—in summer as well as winter—the wearing of flannel next the skin is more necessary, and beneficial even, than when practised by adults.

CLOVE. Syn. Caryoph′yllum (B. P.), L. The flower-buds of the Ciryophyllus aromaticus (Linn.), or clove tree collected before they open, dried, and smoked. Cloves are aromatic, stimulant, carminative, and stomachic; and, according to some, possess febrifuge properties. They are chiefly used as an adjuvant in compound medicines. A few cloves kept in a closet or box prevent moths or mould attacking furs, woollens, &c.

It is a common practice to adulterate this spice in the same manner as cinchona bark. Cloves from which the oil has been distilled are dried and rubbed between the hands, previously moistened with a little sweet oil, to brighten their colour, after which they are mixed up with fresh spice for sale.

Cloves, Mother of. The unripe fruit of the clove tree; they are frequently imported preserved (preserved mother of cloves), and are reputed stomachic and antispasmodic.

Cloves, Oil of. Syn. O′leum caryoph′ylli (B. P.), L. This possesses similar virtues to the unexpanded flower-buds, and is esteemed as a remedy for the tooth-ache. Used to flavour liqueurs and confectionery. Sp. gr. 1·055-1·060.

M. Jacquemin recommends the following as a very delicate test for the presence of carbolic acid when used as an adulterant for oil of cloves. One drop of the suspected oil is mixed with a small trace of solution of aniline by means of a glass rod, and then shaken with 5 or 6 c. c. of distilled water. By the addition of a few drops of sodium hypochlorite to the mixture the characteristic blue coloration due to carbolic acid will be developed in a few minutes, whereas with the pure oil nothing but the purplish-violet colour of aniline will be perceived. Stirring or shaking must be avoided after the addition of the hypochlorite.

CLYS′TERS. See Enema.

COAL. The varieties of this valuable substance may be conveniently described under the three heads Anthracite, Lignite, and Pit-coal (which see). See also Fuel.

COAL-TAR. Coal-tar, one of the products of the destructive distillation of the coal employed in the manufacture of gas, is a very complex substance, consisting of various hydrocarbons, acids, and bases, together with certain resinoid and empyreumatic substances. The principal hydrocarbons yielded by coal-tar on distillation are: benzol, toluol, propyl, naphthalin, and anthracin; of these the first three are fluids, and the last two solids; the most important acids are: carbolic, cresylic, phlorylic, and nosolic; the chief bases are: aniline, chinoline, and lepidine. The quantity as well as the quality of the tar obtained from the distillation of coals varies considerably with the kind of coal used, as well as with the temperature at which the distillation is carried on, the yield of tar being smaller at very high temperatures than when lower ones are employed. Coal-tar, from its antiseptic properties (due chiefly to the carbolic acid it contains), is painted on wood to preserve the latter from decay when exposed to wind and weather. Mixed with coal-dust, saw-dust, and peat-dust, it forms a useful artificial fuel, and when incorporated with pebbles makes an excellent artificial asphalt for pavements. The chief value of coal-tar, however, consists in its being the source of those brilliant dye-stuffs, the coal-tar colours. These, together with the naphtha obtained from its distillation, have converted coal-tar from a worthless and unwelcome waste product of gas manufacture—for the removal of which from their premises the gas makers were formerly only too glad to pay—into a very considerable and important branch of profit and revenue.

The different constituents of the tar are separated from each other by distillation, the various products so obtained being further purified by various processes.

See Tar Colours, Naphtha, Benzol, Anthracene, &c.

CO′BALT. Co. Syn. Reg′ulus of cobalt; Cobalt′tum, L. A metal discovered by Brandt, in 1733. It generally occurs in the same ore as nickel, and the separation of the two metals is a task requiring great patience and expertness. Speiss cobalt and cobalt glance are the ores from which the metal is commonly extracted.

Prep. 1. Dissolve oxide of cobalt in hydrochloric acid, and pass sulphuretted hydrogen gas through the solution, until all the arsenic is thrown down; filter, and boil with a little nitric acid, then add carbonate of potassium, in excess, and digest the precipitate in a solution of oxalic acid, to remove any oxide of iron; wash and dry the residuum (oxalate of cobalt), and expose it to great heat, in a covered crucible lined with charcoal; the product is pure metallic cobalt.

2. Mix equal parts of oxide of cobalt or roasted Cornish cobalt ore, and soft soap, and expose them to a violent heat in a covered crucible.

3. Pass hydrogen gas over oxide of cobalt strongly heated in a porcelain tube.

Prop., Use, &c. Cobalt is a white, brittle metal; unchanged in the air; feebly acted on by dilute hydrochloric and sulphuric acids; has a high melting-point, and is strongly magnetic; sp. gr. 8·5. It is seldom employed in the metallic state, from the great difficulty of reducing its ores, but its oxide (black oxide) is largely employed in the arts. It forms salts with the acids, which are interesting from the remarkable changes of colour which they exhibit. See Ink, Smalts, Zaffre, and below.

Char., Tests. Solutions of the salts of cobalt are known as follows:—1. Ammonia gives a blue precipitate, slightly soluble in excess, giving a brownish-red colour.—2. Potassa gives a blue precipitate, turning to violet and red when the solution is heated.—3. Carbonate of ammonium and carbonate of sodium give pink precipitates; that from the former is soluble in excess.—4. Cyanide of potassium gives a yellowish-brown precipitate, soluble in excess; and the clear solution, after being boiled, is unaffected when mixed with hydrochloric acid.—5. Sulphuretted hydrogen produces no change in acid solutions.—6. Sulphydrate of ammonium gives a black precipitate in neutral solutions.—7. Melted with borax, before the blowpipe, it gives a bead of a magnificent blue colour, almost verging on black, if much is present. Phosphate of sodium and ammonium give a similar bead; but the colour is less intense.

Cobalt, Ac′etate of. Co(C2H3O2)2. Prep. From the carbonate or protoxide and acetic acid. It forms a sympathetic ink which turns blue when heated.

Cobalt, Arseniate of. Co32AsO4, 8H2O. A hydrated native tricobaltous arseniate of cobalt, known as “cobalt bloom.”

Cobalt, Car′bonate of. CoCO3. Prep. By adding an alkaline carbonate to a solution of the nitrate or sulphate. A pale peach-coloured powder, soluble in acids. It contains some hydrate.

Cobalt, Chlo′′ride of. CoCl2. Syn. Hydrochlo′′rate of c., Mu′′riate of c. Prep. By dissolving the carbonate or protoxide in hydrochloric acid; the solution deposits deep rose-red crystals on standing, which contain water. By evaporating the solution by heat, anhydrous blue crystals of the chloride are obtained. Both of them yield a deep rose-red solution with water, which is turned green by a little acid. This solution forms a well-known sympathetic ink, the traces of which become blue when heated. If the solution contains either chloride of iron or chloride of nickel, the traces become green. (Klaproth.) The addition of a little nitrate of copper to the above solution forms a sympathetic ink, which by heat gives a very rich greenish-yellow colour. (Ure.) The addition of a very little common salt makes the traces disappear with greater rapidity, on the withdrawal of the heat. In each case, when the paper is laid aside, moisture is absorbed, and the writing once more disappears. If, however, much heat has been used the traces become permanent.

Cobalt, Ni′trate of. Co(NO3)2. Prep. As the last, substituting nitric for hydrochloric acid; it forms deliquescent crystals.

Cobalt, Ox′alate of. CoC2O4. Prep. As the acetate, from oxalic acid and the carbonate or protoxide; or by double decomposition.

Cobalt, Ox′ides of. Of these there are two, the protoxide and the sesquioxide; besides an acid compound of cobalt and oxygen, to which the name cobaltic acid has been given.

1. Cobalt, Protox′ide of. CoO. Syn. Oxide of cobalt, Grey o. of c., Black o. of c., Cobalt black. Prep. 1. By precipitating a solution of sulphate of chloride of cobalt with carbonate of sodium, and washing, drying, and igniting the powder which subsides.

2. By boiling powdered bright-white cobalt ore (from Cornwall) in dilute nitric acid, and adding a solution of carbonate of potassium, very gradually, until the clear liquor, after the impurities have settled, becomes of a rose colour; and then as long as a precipitate falls; wash and dry it as before.

Prop., &c. A grey powder, turning black on exposure to the air; strongly basic; and forming salts with the acids, having a fine red tint. It is remarkable for the magnificent blue colour it communicates to glass, and by this character its presence may be readily detected before the blowpipe; the substance to be examined being fused with borax on a loop of platinum wire. Used to make blue colours for painters, stains and glazes for enamellers, glass-melters, potters, &c. In medicine it has occasionally been given as a remedy for rheumatism.

2. Cobalt, Sesquiox′ide of. Co2O3. Syn. Perox′ide of Cobalt. A black, insoluble, neutral powder, obtained by mixing solutions of cobalt and of chloride of lime; or, by heating the protoxide to redness in an open vessel.

Cobalt, Phos′phate of. Co3(PO4)2. Prep. As the acetate, substituting phosphoric for acetic acid. An insoluble purple powder, which, when heated along with eight times its weight of gelatinous alumina, produces a blue pigment (COBALT BLUE, COBALT ULTRAMARINE), almost equal in beauty to ultramarine. (See below.)

Cobalt, Sul′phate of. CoSO4. By boiling sulphuric acid on the metal, or by dissolving the oxide in the acid. It forms reddish crystals, soluble in 24 parts of water.

Cobalto-Ultramarine. A fine blue pigment, prepared by mixing freshly precipitated alumina, 8 parts, with phosphate or arseniate of cobalt, 1 part; drying the mixture, and then slowly heating it to redness. By daylight the colour is pure blue, but by artificial light it is violet. See Blue pigments.

COCA. Erythroxylon Coca. This plant is grown largely in Peru and Bolivia. The Bolivian coca is said to be much superior to the Peruvian. The best kind is believed to come from the province of Yungas, and the most inferior description from Peru. The consumption of Coca in Peru, Bolivia, and in some of the provinces of the Argentine Confederation is enormous. In small doses it is supposed to act as a stimulant and to aid digestion; in large ones it is said to possess dangerous narcotic properties. The mountaineers in South America state they are enabled to reach high elevations without difficulty of respiration, and to stave off the feeling of hunger by chewing the leaves during their ascents. “Good quality coca should have its leaves unbroken, of a medium size, bright green in colour, and of an odour somewhat combining that of hay and chocolate. The taste is bitter, and when masticated, coca is said to yield easily to the teeth. Infused in hot water, it has a beautiful green colour, which, however, is much darker from inferior leaves. An infinite number of varieties are recognised between the best and the lowest quality, which has a disagreeable smell and a colour resembling roasted coffee. The leaves are also bent and broken, scarcely a whole leaf being found amongst them.” The statements as to the effects of coca are conflicting, as will be seen from what follows:—Sir R. Christison, writing to the ‘British Medical Journal,’ April 29th, 1876, states he was hardly sensible of the fatigue of two mountain descents made from Ben Vorlich after chewing coca leaves. That, as a consequence of his doing so, hunger and thirst were suspended for a long time, but that eventually appetite and digestion were unaffected. He made trial during the first descent of 60 grains, and of the second, undertaken eight days after, of 90 grains of coca.

Mr Dowdeswell, in a communication to the ‘Lancet,’ May 6th, 1876, says that, contrary to the experience of Sir R. Christison, he found no decided effects produced after consuming nearly a pound of the leaves, which were taken in all forms and at all hours for nearly a month. They failed to produce the slightest excitement, not giving rise even to the feeling of buoyancy and exhilaration which is experienced from mountain air or a draught of spring water.

In the ‘Canadian Pharmaceutical Journal’ for August, 1877, there is a paper by Mr Shuttleworth, wherein results the opposite to those of the last-named gentlemen are recorded. Mr Shuttleworth states that the members of a club established at Toronto for the purpose of playing at La Crosse, a very violent and fatiguing pastime, were almost unanimous in ascribing their invariable success over their numerous adversaries to the use of coca leaves during their contests; their opponents not employing the plant. The antagonists of the club were men of stronger build and physique as well as more accustomed to out-of-door pursuits, and were besides trained players.

The same writer says that in South America care is taken to procure the leaves in as fresh a state as possible, and that many writers have ascribed the want of effect to old leaves.

The ‘British Medical Journal’ of March 10th, 1877, contains a communication from Dr T. McBean, who states that he has found the administration of coca leaves useful in typhoid fever, as well as in other febrile diseases.

CO′COA (kō′-ko). Syn. Caca′o. An alimentary substance formed of the roasted seeds of the Theobroma Cacao, a tree belonging to the natural order Byttneriaceæ. This definition is equally applicable to chocolate, but we commonly class the preparations containing sugar and flavouring substances under that head, and the unsweetened and cheap preparations under COCOA. The cocoa-seed or berry must not be confounded with the cocoa-nut, which is the fruit of a palm (Cocus nucifera). The cocoa tree is a native of Mexico, and is now more or less extensively grown throughout Central America, Brazil, Peru, Venezuela, Caraccas, Ecuador, Grenada, Demerara, Essequibo, Guayaquil, and Surinam; with some of the West India Islands, foremost among which stands Trinidad. It has also been introduced with more or less success into Africa, the Mauritius, Madagascar, Bourbon, the East Indies, Australia, and the Philippine Islands. The following is a list of the principal kinds of cocoa, in the order of their commercial value:—Caraccas, Surinam, Trinidad, Grenada, Jamaica, Dominica, Guayaquil, Venezuela, Bahia, Brazil, St. Lucia. It seems probable that some of the highest kinds of cocoa do not find their way into this country, but are consumed by the inhabitants of Spain.

Prep. The pods containing the seeds are gathered when ripe, and after having lain for a day and a night are opened, and the seeds, which are taken out by hand, are submitted to what is termed the sweating process. They are first placed on a sloping floor or in baskets, so that the chief part of the pulp in which they are enveloped may drain off, and are then shut up in a close box, and left for 24 to 48 hours, according to the season and weather, after which they are turned out in the sun to dry. Upon a nice performance of the sweating process, which may be likened to malting, the value of the cocoa greatly depends. When quite dry, the seeds are packed in barrels or bags, and are ready for shipment. The process of roasting is effected in a metal cylinder, with holes at each end, through which the vapour generated is allowed to escape. When the aroma is sufficiently developed the seeds are cooled, and then passed to a ‘kibling mill,’ which removes the husks and skins from the ‘nibs’ (see below).

Prop., Constituents, &c. Cocoa, when unadulterated, forms a wholesome and highly nutritious beverage. Its active principle is theobromine, an alkaloid greatly resembling caffeine, the active principle of coffee and tea. A peculiar concrete oil, called cocoa-butter, or, more correctly, butter of cacao, is another important constituent, forming more than half the weight of the seed. The presence of about 20% of albumen gives to cocoa its nutritive character.

Average composition of cocoa seeds.—(Wanklyn.)

Per cent.

Fat (cocoa butter) 50·00

Albumen, fibrine, and gluten 18·00

Starch 10·00

Gum 8·00

Colouring matter 2·60

Water 6·00

Theobromine 1·50

Ash 3·60

Loss 0·30

100·00

Dr Letheby calculated that a pint of cocoa made with 1 oz. of ground nibs would contain the following proportions of nutritious matters:—

Nitrogenous matters 96·2 grains

Patty matter 218·8 ”

Gum, sugar, and extractive 65·6 ”

Mineral matters 17·5 ”

Total extracted 398·1

Adult. Much of the cheap stuff sold as genuine cocoa is shamefully adulterated. Out of 68 samples of cocoa and chocolate examined by the ‘Lancet’ commission, 39 contained coloured earthy substances, as reddle, Venetian red, umber, &c. To some, chalk or plaster of Paris had been added, for the purpose of increasing the weight. Many of the samples consisted of sugar and starch, with only sufficient cocoa to impart a flavour. Cocoas containing a moderate amount of arrow-root or other starch must not be considered adulterated articles, for it is impossible to render cocoa soluble, or rather emulsive, without the addition of some diffusible substance.

By an examination of the ash the presence of any mineral adulterant may be detected. Mr Blyth says the amounts of ash in genuine cocoa should never exceed 5 per cent. The seed of the cocoa consists of husk and seed proper. Under the microscope the husk exhibits on its surface a number of tubular fibres, filled with granular matter and minute corpuscles. It consists of three membranes; the first being a single layer of elongated cells; the second (forming the chief portion of the husk) of angular cells, enclosing mucilage, and also containing a few spiral vessels and woody fibres. The third membrane is very thin and delicate, and is made up of small angular cells containing minute globules of fat. The seed is composed of minute cells containing starch. The starch corpuscles are very small, with a trace of inulin. (See cuts on previous page.)

Cocoa, Flake. This is formed by grinding the nibs in a mill, consisting of two cones, working one inside the other. Pure flake cocoa is not a diluted or amalgamated article; in other words, it contains no sugar, and but a trace of starch.

Cocoa Nibs. The bruised, roasted seeds, freed from husk and membrane. They ought to be of a dull-red or greyish colour, but are frequently given a bright-red colour by a coating of Venetian red.

Cocoa, Sol′uble. From cocoa nibs and substances which are readily soluble or diffusible in water, ground together. Sugar and sago or arrow-root are the diluents used by respectable makers, but all kinds of starches, coloured with Venetian red, are used for the trashy articles which are sold to the poor. No form of cocoa is really soluble, but by the addition of easily diffusible substances an article is produced which is capable of forming an emulsion with boiling water. The following are the principal varieties of the so-called soluble cocoa:—

1. Cocoa, Granulated. From cocoa nibs and sufficient sugar and arrow-root to keep the fatty particles from forming a pasty mass. As it is impossible to granulate the nibs without the admixture of some other substance, those makers who declare that their granulated cocoas are perfectly pure do not act honestly towards their customers.

2. Cocoa, Homœopathic. A kind of soluble cocoa prepared with arrow-root, but without sugar.

3. Cocoa, Iceland-moss. From cocoa and Iceland moss, freed from its bitter principle, cetrarine. This form of cocoa was introduced by Messrs Dunn and Hewett, and is said to form a very valuable article of diet for invalids.

4. Cocoa, Maravilla. This is stated to be “the perfection of prepared cocoa.” It consists of cocoa, sugar, and sago flour, the last two being in great excess.

5. Cocoa, Caraccas. This is similar to the last, being a mixture of cocoa, sugar, and sago flour. The cocoa used in its manufacture is said to be imported from the Caraccas, on the north coast of South America, and to possess a peculiarly delicious flavour.

The amount of flour or starch in these so-called soluble cocoas frequently exceeds 40 per cent., and the amount of sugar 20 per cent. They have been not inaptly called “soups.”

Within the past year or two a new variety of soluble cocoa has been brought into the market. It is sold under various names, thus, ‘Theobromine, or Concentrated Cocoa,’ ‘Cocoa Essence,’ ‘Cocoatina,’ &c. We have examined many of these varieties, and find them to consist of pure cocoa deprived of about two thirds of its fat. It appears very suitable for people of weak digestion.

Obs. No warm drink that we take approaches cocoa in its nutritive character, because, while performing to a certain extent the exhilarating work of coffee or tea, it presents to the stomach a very considerable quantity of nitrogenous and carbonaceous matter; this advantage is partly due to the fact that cocoa is taken in the form of an emulsion, instead of an infusion or decoction.

Cocoa for the table is readily prepared from the soluble varieties by simply pouring boiling water upon the powder. From cocoa nibs, or flaked cocoa, the beverage is prepared by first pouring boiling water upon them, and then allowing the mass to simmer from 4 to 6 hours. The cocoa must on no account be allowed to boil, for in that case a coagulum will be formed, which cannot be dissolved in water.

COCOA-NUT OIL. A species of vegetable butter obtained from the common cocoa nut—the fruit of Cocos nucifera, the cocoa palm. It is separated from the dried kernel by hydraulic pressure. It contains olein, and a solid fat often used as a candle material. Large plantations of the cocoa palm, connected with Price’s candle company, exist in Ceylon. Cocoa-nut oil is often confounded with cocoa- or cacao-butter, which is the produce of a very different plant, namely, Theobroma cacao. See Cocinic acid, Cocoa, Stearic acid, &c.

COC′CULUS IND′ICUS. Syn. Indian berries, Indian cockles, Levant nut, Louse grains; Bac′ca Orienta′lis, Cocoulus piscator′ius, &c., L. The fruit of the Anamirta paniculata, a shrub which abounds on the sandy shores of Malabar, and several other islands in the Indian Ocean. The kernels should fill at least two thirds of the fruit.

It is a dark, tough, hard, wrinkled berry, about the size of a cherry, and possesses an intensely bitter taste. The berry consists of two parts, the husk and the kernel, the former being hard and difficult to bruise, and the latter soft and containing a large proportion of fatty matter.

Uses, &c. Cocculus indicus is poisonous to all animals, and to most vegetables. It is never employed internally in medicine, but an ointment, formed by mixing the powder with lard, has been used to destroy pediculi and in porrigo. Its active principle is picrotoxin, a peculiar needle-shaped, crystalline substance, possessing all the poisonous properties of the berry in an exalted degree, and of which it contains about 2 per cent. Its effects on the system are, to produce giddiness, convulsions, and insensibility, frequently ending in death. A small portion of the cocculus indicus imported is used by poachers, and a still smaller quantity to destroy vermin, the remaining, and by far the greater part, being employed to adulterate beer and even wine. “In our own analytical experience we have seldom found this substance in beer purchased from a respectable house. We have detected it, however, in beers purchased in the lowest localities in London and elsewhere, but have every reason to suspect that the adulterants had been added by the publican himself, in the form of an extract known in the trade by the name of ‘B. E,’ or black extract.” (Harkness.)

Chemists and druggists are liable to severe penalties if they are found supplying cocculus indicus, or any extract of the same, to brewers or publicans. See Beer, Porter, &c.

COCH′INEAL. Syn. Coc′cus (B. P.), L. Grana fina, Span. The Coccus Cacti (Linn.), an insect found upon the cactuses of Mexico. It is of great value as a dye stuff. The female insects, when matured, are brushed off the plants and dried by artificial heat. The entire insect is used. There are two varieties known in commerce—silver cochineal, which has a purplish-grey or silver-grey colour; and black cochineal, which is smaller, and of a reddish or purplish-black colour. The former is that commonly met with.

Adult. Genuine cochineal has the sp. gr. 1·25. It is commonly increased in weight by slightly moistening it with gum-water, and then rouncing it in a bag, first with sulphate of baryta, and then with finely powdered bone-black. In this way its sp. gr. is raised to 1·35, in consequence of being loaded by about 12% of useless foreign matter.

Herr Durwell, a German chemist, states that he found a sample of cochineal adulterated with sulphate of zinc. He thinks the sophistication was probably effected by immersing the cochineal in sulphate of zinc, and then in an alkali, whereby the white pulverulent aspect of the genuine article was imparted, and the weight increased.

The following is a method which has been given for estimating the value of samples of cochineal:—Grind the samples to be tested to a fine powder, weigh out 2 or 2⁄2 grammes, and boil this amount in a capacious narrow-necked flask, with 750 c. c. of water for 1 hour; filter immediately through dry paper filters, and allow it to cool. To test it 50 c. c. are measured in a flask of that capacity, and poured into another flask of about 200 c. c., and the measuring vessel rinsed with a definite quantity of water, say 10 to 15 c. c. A weak solution of permanganate is then run in from a burette with a glass cock, the flask being shaken after the addition of every 10 c. c. So much permanganate solution is then added that the cochineal extract shall be charged from its original colour to a pink of the faintest shade—almost yellow, in fact, but never reaching a full yellow. This pink shade should be persistent, that is, it should not turn yellow after standing fifteen minutes; and after a little practice it will be found very easy to obtain the tinge, which shows that the colouring matter is almost but not quite destroyed.

When a number of samples are to be compared, arrange an equal number of 200 c. c. flasks and test-tubes on the table, a tube standing in its rack in front of each flask. Then the same number of c. c. of the permanganate solution (which should be, at least, so weak that bulk for bulk of this and the cochineal solution will be required) is run into each flask, taking care to use too little to completely destroy the colouring matter in all.

The flasks are well shaken and allowed to stand for ten minutes. Part of the contents of each is then poured into the corresponding test-tube, and a glance of the tubes as they stand side by side will show which is the least affected by the bleaching liquid. This sample having been selected to serve as a standard, the contents of the test-tube are returned to the flask, and more permanganate solution is cautiously added, until a very faint pink tinge, which a fraction of a c. c. will turn to a full yellow, is obtained. The number of c. c. used having been noted, a fresh trial is made, in which the c. c. required, minus one, are used, the flask agitated, and the last c. c. or part of it, as the whole may not be necessary added.

If the two results agree, the next sample is treated in the same way, and so until all are tested.

A final trial may be made by measuring 50 c. c. of each solution into its flask, running in the permanganate in the ascertained amount into each as quickly as possible, letting the flasks stand ten minutes, and then making a comparison of all in the test-tubes. If the shades are not exactly alike, a pretty good guess can generally be made of the fractions of c. c. required, which should be added, the contents of the tubes being joined to that in the flasks, and a second or third comparison thus made.

This is a rather long description of what is in practice a very simple and good process, the three principal points to be borne in mind being—

1st. To use a weak solution of permanganate.

2nd. To have a very faint pink colour as a standard of comparison.

3rd. To let the liquids remain after agitation together ten or fifteen minutes before comparing them.

Uses, &c. Cochineal is principally used to prepare lake and carmine, and in dyeing. Its colouring principle is freely soluble in water. It imparts every variety of scarlet and crimson to textile fabrics previously prepared with alum, tin, and other mordants. It is also used to colour liqueurs, tinctures, and confectionery. It has been recommended as an antispasmodic and anodyne, in hooping-cough and neuralgia.—Dose, 10 to 60 gr., in powder, confection, or tincture. See Carmine and Carminic acid.

COCIN′IC ACID. Syn. Cocostear′ic acid. A crystalline, fatty acid, obtained by the saponification of COCOA-NUT OIL. See Stearic acid.

COCK-METAL. Syn. Pot Metal. Copper, 20 lbs.; lead, 8 lbs.; litharge, 1 oz.; antimony, 3 oz. Another variety consists of copper, lead, and sometimes a little zinc.

COCKROACH. See Blatta.

COD. Syn. Ga′dus Mor′rhua (Ph. L.), Mor′rhua vulgaris (Linn.), Asel′lus (Pliny), L. A fish common in the seas of the northern hemisphere, from about 40° to 75° of latitude. The flesh forms a most wholesome and excellent article of food. The best fish are very thick about the neck; and, when fresh, are marked by the redness of the gills, freshness of the eyes, and the whiteness and firmness of the flesh. The fish so largely imported from Newfoundland (Newfoundland fish) are cod beheaded, split open, gutted, and salted. They are caught by millions on the ‘Grand Bank.’ Cod-sounds are pickled in brine and also made into isinglass. The spawn is made into CAVIARE, and the liver is both pressed and boiled for its oil (see below).

Cod is generally cooked by boiling it, but is sometimes baked, or cut into slices and broiled or fried. Cod’s head and shoulders with oyster sauce is a favorite dish. Shrimp and anchovy sauce are also good additions.

COD-LIV′ER OIL. Syn. Mor′rhuæ o′leum, B. P.; O′leum jecor′is Asel′li, L.; Huile de Morue, Fr. The oil obtained from the liver of the common cod (oleum e jecore comparatum).

Prep. 1. The livers, being removed from the fish, are piled on layers of fir-twigs placed in tubs perforated at the bottom, and are allowed to remain for a considerable time exposed to the sun and air. As the livers putrefy, the oil runs out and flows through the holes in the tubs into vessels placed to receive it.

2. The partially decomposed livers, cut into pieces, are heated in iron pots without water, and the oil is poured off and set aside to deposit impurities.

3. (Savory.) The livers taken from the fresh fish are carefully washed. The large veins are then divided through their whole length, and any blood in them is carefully rinsed away. The livers are now cut into pieces, again washed and drained, and afterwards placed with a small quantity of water in vessels gently heated by steam. As the heat increases, the oil separates and rises to the surface, from which it is skimmed off; and after well cooling, to allow the deposit of some of the margarin, it is repeatedly filtered through flannel bags and finally through paper. This process gives a fine, clear, straw-coloured oil, having but a slight smell and taste.

4. (Donovan.) The perfectly fresh livers are placed in a metallic vessel and heated with constant stirring to 180° Fahr., by which treatment they break down into a uniform pulpy, liquid mass. This mass is immediately transferred to calico bags, whence the oil drains out; after filtration, while still warm, this oil is sufficiently pure for use.

Obs. Three kinds of cod-liver oil are usually distinguished—the pale yellow, pale brown, and dark brown. The latter is the most impure; its odour and taste are extremely disagreeable. The most conflicting opinions have been expressed by medical men as to the relative value of the light brown and yellow varieties. Ozonised cod-liver oil is said to be prepared by passing oxygen into the oil, and then exposing it to sunlight. Dr Letheby applied the most delicate tests to this much-vaunted remedy, but was not able to detect the slightest trace of ozone.

Prop. and Uses. Cod-liver oil has acquired much reputation for its remedial powers in pulmonary consumption, scrofulous and other glandular affections, chronic gout and rheumatism, certain skin diseases, and several other ailments. It is generally supposed that the iodine and bromine, which are present in minute quantities in this fish, are the substances to which it owes its efficacy. “Dr De Jongh refers its virtues to the presence of both iodine and the elements of the bile. Our own researches lead us to infer that one of its most active constituents is free phosphorus. Good cod-liver oil contains fully ·02 of this substance, as well as about ·09 of phosphoric acid. Now, the marked action of minute doses of phosphorus on the nervous, vascular, and secreting organs, is well known to every experienced surgeon. The difficulty, however, of bringing it into a form adapted for administration has hitherto prevented phosphorus being extensively employed as a therapeutic agent. This obstacle is removed by the employment of cod-liver oil. Nature has here provided a simple remedy, which the ingenuity of man has failed to produce artificially. This opinion is borne out by the facts, that cod-liver oil cures those forms of scrofula and other diseases which do not yield to iodine, and that those varieties of the oil are the most active which contain the most free phosphorus. We, therefore, think it reasonable to conclude, that the efficacy of cod-liver oil depends on the joint action of the minute quantities of iodine, phosphorus, and the elements of the bile which it contains, and not on any one separately; and that no substance, at present known, can be used as a substitute for it.” (Cooley.)—Dose, 1 to 8 dr., in water, syrup, or orange juice; or made into an emulsion with 1 fl. oz. of peppermint water.

M. Duquesnel states that cod-liver oil flavoured with essence of eucalyptol, in the proportion of one part of the essence to a thousand, has neither the taste nor the odour of cod-liver oil. It is taken with facility, only leaving at the back of the mouth and on the tongue the taste of the essence. M. Duquesnel adds that the offensive eructations arising from cod-liver oil are completely corrected.

Cod-liver Oil Jelly. Take of cod-liver oil, 85 parts; isinglass, 3 parts; sugar, 8 parts; water, 4 parts. It forms a semi-transparent jelly of a yellowish-green colour, having a strong odour, but less strong taste of the oil. The advantages of this preparation are—its easy administration, complete retention, and assimilation by the weakest stomach. A teaspoonful is said to be equal to a tablespoonful of the ordinary oil. A lemon flavour may be imparted to it with advantage if desired.

Cod-liver Oil and Lacto-Phosphate of Lime. (Shinn.) Cod-liver oil, 1 pint; oil of bitter almonds, peppermint, and winter green, of each 10 drops; powder of gum Arabic 4 oz.; sugar, 6 oz.; solution of lacto-phosphate of lime (60 gr. to 1 fl. oz.), 6⁄2 fl. oz.; lime water, 6⁄2 fl. oz. Mix the gum and sugar in a capacious mortar, and make a smooth mucilage with the lime water and 3 oz. of the solution of lacto-phosphate of lime. Add the volatile oils to the cod-liver oil, and gradually triturate them with the mucilage, until a perfect emulsion is formed. Finally, add the rest of the solution of the lacto-phosphate of lime, and mix thoroughly. The solution of lacto-phosphate of lime is made by saturating a solution of lactic acid with freshly precipitated phosphate of lime.

Cod-liver Oil with Iodide of Iron. Triturate iodide of iron, with cod-liver oil, 4 gr. to the ounce, until dissolved. Horsley’s patent is as follows:—Dissolve 22 scruples of iodine in a gallon of cod-liver oil, at a temperature of 140° Fahr., in a water-bath. Add to the solution 8 scruples of iron (reduced by hydrogen), and heat to 180° Fahr., until the combination is complete.—Dose, 1 dr. to ⁄2 oz.

Cod-liver Oil, Phosphorated. (Lancet.) Pure unoxidised phosphorus, 2 gr.; almond oil, 2 oz. Put into a bottle, stoppered, and immerse the same in a water-bath; apply heat until the temperature of the oil is about 180° Fahr., as directed by the B. P., in the preparation of oleum phosphoratum; shake up occasionally, and again put the bottle into the water if necessary, until a perfect solution is obtained; then add about 10 oz. of cod-liver oil, and again immerse in the water-bath; finally, make up the measure with cod-liver oil to 25 oz. One drachm so prepared will contain over the ⁄100th of a grain of pure phosphorus.

Cod-liver Oil, Emulsion of. Cod-liver oil, 8 fl. oz.; tragacanth, 1 dr.; powdered white sugar, 4 dr.; oil of gaultheria, 9 drops; oil sassafras, 1 drop; oil bitter almonds, 10 drops, water, 8 oz. Dissolve the tragacanth and sugar in water, and strain. Add to this first the essential oils, and then incorporate the cod-liver oil.

Cod-liver Oil and Hypophosphites, Emulsion of. (Canadian ‘Pharmaceutical Journal’). Powder of gum tragacanth, ⁄2 oz.; glycerin, 3 oz.; water, 9 oz. Rub the tragacanth with the glycerin, and add the water gradually. To this mucilage add the following solution:—Hypophosphite of lime, 4⁄2 dr.; hypophosphite of soda, 2⁄4 dr.; hypophosphite of potash, 2⁄4 dr.; sugar, ⁄4 lb.; boiling water, 12 oz. Make the admixture gradually with brisk trituration. To this medicated mucilage add the following:—Otto of almonds, bitter, 10 drops; otto of cinnamon, 5 drops; otto of canella, 5 drops; alcohol, 6 oz. The whole will now form a semi-transparent mucilaginous liquid of about 37 fl. oz. in bulk. To this add gradually an equal measure of cod-liver oil, and mix thoroughly. In practice it is advisable to work on small quantities, say half a pint of each in a No. 8 mortar. If care is taken the product will be very satisfactory.

CODE′IA. C18H21O3. Aq. Syn. Code′ine. An alkaloid discovered by Robiquet associated with morphia.

Prep. Dissolve commercial hydrochlorate of morphia in water, and precipitate the morphia with ammonia. Codeia is left in solution, and is obtained in octahedral crystals by spontaneous evaporation. It may be further purified by solution in ether. By the addition of a little water to the ethereal solution and spontaneous evaporation it may be obtained quite pure and in a crystalline state.

Obs. The morphia may be recovered by digesting the precipitate in weak solution of potassa.

Prop., &c. Freely soluble in alcohol and ether; soluble in 80 parts of cold and 17 parts of boiling water. Its solution in the latter, by slow evaporation, yields large, transparent octahedra. With the acids it forms crystallisable salts. These possess the singular property of producing a general and violent itching of the surface of the body when administered internally. The same symptoms frequently follow the exhibition of opium and hydrochlorate of morphia, and are referred to the presence of codeia. The commercial muriate of morphia frequently contains 3% to 4% of codeia.

Tests. It is distinguished from morphia by not becoming blue on the addition of perchloride of iron, nor turning red with nitric acid; and by not being precipitated by ammonia, when dissolved in hydrochloric acid and mixed with a large quantity of water. Unlike morphia, it is insoluble in weak solution of potash, and is soluble in ether. The salts of codeia are known by tincture of galls throwing down a copious precipitate from their solutions; this does not occur with the salts of morphia. It is distinguished from meconia by its aqueous solution showing an alkaline reaction with test-paper.

COFFEE. The seeds or berries of the Coffea arabica (Linn.) or coffee plant; a shrub of the natural order Cinchonaceæ, sub-order Coffeæ, indigenous in the low mountainous districts of Arabia Felix, and largely cultivated in various other parts of the world. About 40 millions of pounds of coffee are annually consumed in this country, and the consumption for the whole world has been estimated at about 600 millions of pounds. The seeds are roasted and ground, and used in the form of a decoction or infusion. The term coffee is applied to the prepared beverage as well as to the seeds. The valuable properties of coffee are mainly due to the presence of the alkaloid CAFFEIA or CAFFEINE.

Payen gives the following as the composition of the coffee-berry:—

Water 12·000

Woody tissue 34·000

Fixed fatty matters 10 to 13·000

Gum, sugar, and vegetable acids 15·500

Nitrogenous matter allied to legumin (vegetable casein) 13·000

Free caffein 0·800

Compound of caffein with potash 3.5 to 5·000

Solid fatty essence 0·002

Aromatic essential oil 0·001

Saline matters 6·697

100·000

Prep., &c. The finest kind of coffee is that called mocha, from Aden, but that in common use is principally supplied from the British plantations in the West Indies. The selection being made, the berries are carefully roasted in revolving cylinders by a gradually applied heat, until the aroma is well developed and the toughness destroyed. Too much heat is avoided, as the volatile and aromatic properties of the coffee, and, consequently, the flavour, are thereby injured; whilst, on the other hand, if the berries are roasted too little, they produce a beverage with a raw, green taste, very liable to induce sickness and vomiting. When properly roasted, coffee has a lively chocolate-brown colour, and should not have lost more than 18% of its weight by the process. If the loss exceeds 20%, the flavour suffers in proportion. The roasted coffee should be placed in a very dry situation, and excluded from the air as soon as possible. It loses flavour by keeping, and also powerfully absorbs moisture from the atmosphere by reason of its hygrometric power.

Qual., &c. Coffee promotes digestion, and exhilarates the spirits, and when strong, generally occasions watchfulness, but in some phlegmatic constitutions induces sleep. Drunk in moderation, especially if combined with sugar and milk, it is perhaps the most wholesome beverage known. The various qualities that have been ascribed to it by some persons such as dispelling or causing flatulency, removing dizziness of the head, attenuating the blood, causing biliousness, &c., appear to be wholly imaginary. In a medical point of view it has been regarded as a cerebral stimulant and anti-soporific, and as a corrector of opium. As a medicine it should be strong, and is best taken only lukewarm.

Adult., &c. The principal substances used for the purposes of adulteration are caramel, roasted chicory, roasted locust beans, roasted corn, &c. Chicory being now charged with the same amount of duty as coffee, is not considered in a revenue point of view an adulteration; nevertheless, when we contrast coffee with chicory, we at once see the vast superiority of the former over the latter, thus:—

Coffee is the fruit of a tree, whilst chicory is the root of an herbaceous plant, and it is well known that more virtues exist in fruits and seeds than in roots.

Coffee contains three active principles, viz. an essential oil, caffeia, and tannic acid, and these exercise a powerful influence on the system, retarding the waste of the tissues of the body, exciting the brain to increased activity, and exhilarating without intoxicating. Chicory contains none of these constituents.

Coffee exerts on the system highly beneficial physiological effects; chicory possesses medicinal properties, which are not desirable in an article of food.

Chicory, therefore, is very objectionable, and when a dealer sells a mixture of coffee and chicory for pure coffee, as is almost invariably the case, he is guilty of selling an adulterated article, and ought to be punished accordingly.

The adulteration with caramel or chicory may readily be detected as follows:—

1. A spoonful of pure coffee placed gently on the surface of a glass of cold water will float for some time, and scarcely colour the liquid; if it contains caramel or chicory, it will rapidly absorb the water, and, sinking to the bottom of the glass, communicate a reddish-brown tint as it falls. Another method of applying this test is by expertly shaking a spoonful of the suspected coffee with a wine-glassful of cold water, and then placing the glass upon the table. If it is pure, it will rise to the surface, and scarcely colour the liquid; but if caramel or chicory is present, it will sink to the bottom, and the water will be tinged of a deep red as before.

2. The brown colour of decoction or infusion of roasted coffee becomes greenish when treated with a per-salt of iron; and a brownish-green, flocculent precipitate is formed. The colour of chicory is only deepened, but not otherwise altered, and no precipitate is formed, under the same treatment. A mixture of chicory and coffee retains a brownish-yellow colour after the precipitate has subsided, and the liquid appears brownish yellow by refracted light. The addition of a little weak ammonia water aids the subsidence of the precipitate.

3. Under the microscope (see Chicory) the presence of chicory may be readily detected by the size, form, and ready separation of the cells of the cellular tissue, and by the presence and abundance of the pitted tissue or dotted ducts, which are absent from coffee, and by the size of the spiral vessels, which are very small in coffee. The most characteristic structure, however, and that by which chicory can be easily identified, is the lactiferous tissue. Roasted corn, and other amylaceous substances, may also be detected, in the same way, by the peculiar size and character of their starch grains.

Under the microscope the berry is seen to consist of a hard, tough tissue, that resists even long soaking. The testa covering the berry is made of lengthened cells with oblique markings resting on a thin membrane, almost structureless. These oblique markings of the cells are so characteristic as to render the cells distinguishable from every other tissue. The substance of the berry consists of angular cells, each one of which contains minute drops of oil. This oil is in some measure driven off during the process of roasting, which, however, leaves the structure unimpaired where it is not charred.

Roasted corn, beans, &c., may be detected by the cold decoction striking a blue colour with tincture of iodine. Pure coffee is merely deepened a little in colour by this substance.

4. (A. H. Allen.) The amount of ash in genuine coffee does not exceed 4·5 per cent.; chicory yields 5 per cent. The silica in coffee ash never exceeds 1 per cent., while in chicory it varies from 10-36 per cent. The average soluble ash in coffee is 3·24, while in chicory it is 1·74 per cent. By determining the soluble ash S, the per-centage of pure coffee C may be calculated thus:—

(100 S - 174)
C = 2 ——————
3

The density of coffee-infusion is determined by heating the powder with 10 times its weight of cold water, raising the liquid to the boiling point, filtering, and taking the gravity at 15·5° C. Taking the density of pure coffee-infusion at 1008·6, and that of chicory at 1020·6, the per-centage of pure coffee C in the sample may be calculated from the equation

100(1020 - D)
C = ——————
12

where D represents the density of the infused sample. The relative tinctorial power of an infusion of a sample of coffee is determined by boiling a given weight with 20 c. c. of water for a few minutes, filtering, and again boiling the residue until thoroughly exhausted. An equal weight of a standard mixture of equal weights of pure coffee and chicory is treated in a precisely similar manner. The standard solution is made up to 200 c. c., that of the sample to 100 c. c.; 10 c. c. of the latter are put into a narrow burette, and some of the standard into a test tube of exactly equal bore. If the tints are exactly the same, the sample consisted of pure coffee; if chicory is present, water must be added to the sample until the tints are the same. Each c. c. of water represents 5 per cent. of chicory. The presence of leguminous seeds or cereals may be detected by boiling the sample with animal charcoal and water, filtering, and testing for starch in the cold liquid with iodine. Neither coffee nor chicory contains starch.

Obs. A few years ago the attention of the scientific world was drawn to the value of roasted coffee leaves, as furnishing materials for a beverage unexcelled in excellence by the coffee berry itself. It appears that the leaves, prepared for use, may be purchased for 1⁄2d. per lb., or packed ready for export at 2d. per lb. “That this preparation contains a considerable amount of the nutritious principles of coffee is evident from the analysis; but as the leaves can only be collected in a good state at the expense of the coffee-bush, it is doubtful whether the coffees produced by the berries be not, after all, the cheapest, as it certainly is the best.” (Jury Report, Exhibition, 1851.) Coffee for the table is best prepared with the aid of a French cafetière, or coffee biggin, furnished with a percolator or strainer, which will permit a moderately rapid filtration. To produce this beverage in perfection, it is necessary to employ the best materials in its preparation—fresh roasted and fresh ground. “At least 1 oz. of coffee should be used to make 3 common-sized coffee-cupfuls, with 1 teaspoonful of freshly roasted and ground chicory. If desired strong, the quantity of both should be doubled.” (Cooley.) Many habitual coffee drinkers cannot tolerate the use of chicory, which is a doubtful improver of coffee. The prevailing fault of the coffee made in England is its want of strength and flavour. The coffee-pot should be heated previously to putting in the coffee, which may be done by means of a little boiling water. The common practice of boiling coffee is quite unnecessary, for all its flavour and aroma is readily extracted by boiling hot water. Indeed, all the “useful and agreeable matter in coffee is very soluble, it comes off with the first waters of infusion, and needs no boiling.” (Ure.) Should prejudice, however, induce the housewife or cook to boil her coffee, it should be only just simmered for a minute, as long or violent boiling injures it considerably.

When coffee is prepared in a common pot, the latter being first made hot, the boiling water should be poured over the powder, and not, as is commonly the plan, put in first. It should then be kept stirred for 4 or 5 minutes, when a cup should be poured out and returned again, and this operation repeated 3 or 4 times, after which, if allowed to repose for a few minutes, it will generally become fine of itself. In all cases, where a percolator is not used, the liquor should be well stirred up several times before finally covering it up to settle for use.

Amongst the various descriptions of coffee pots in use we may mention those of French make, consisting of two cylindrical vessels, the upper having a metal strainer, on which the ground coffee is placed, and through which the clear infusion runs into the lower one; Loysell’s—an apparatus making very good coffee, and as one of the latest, an ingenious and inexpensive coffee pot, known as the “Kaffee Kanne,” devised by Mr Ash, of Oxford Street. Ash’s “Kaffee Kanne” consists of an ordinary biggin, surrounded by a jacket containing boiling water. The coffee is made by percolation in the inner vessel, and being kept at the point of ebullition by the surrounding boiling water, yields a beverage of excellent flavour and aroma.

Coffee is sometimes clarified by adding a shred of isinglass, a small piece of clean eel- or sole-skin, or a spoonful of white of egg. An excellent plan, common in France, is to place the vessel containing the made coffee upon the hearth, and to sprinkle over its surface half a cupful of cold water, which from its greater gravity descends, and carries the ‘foulness’ with it. Another plan sometimes adopted is to wrap a cloth, previously dipped into cold water, round the coffee-pot. This method is commonly practised by the Arabians in the neighbourhood of Yemen and Moka, and rapidly clarifies the liquor, unless a very large quantity of chicory is present. It should be recollected that the use of isinglass, white of egg, and all like artificial finings, remove much of the astringency and vivacity of the liquor.

The French, who are remarkable for the superior quality of their coffee, generally allow an ounce to each large coffee-cupful of water, and they use the coffee both newly ground and freshly roasted. A shred of saffron, or a little vanilla, is frequently added, whilst the percolating coffee-pot is generally employed. When the Parisian uses a common coffee-pot he generally divides the water into 2 parts. The first portion he pours on boiling hot, and allows it to infuse for 4 or 5 minutes; he then pours this off as clear as possible, and boils the grounds for 2 or 3 minutes with the remaining half of the water. As soon as this has deposited the sediment it is decanted, and mixed with the infusion. The object of this process is to obtain the whole of the strength as well as the flavour. The infusion is thought to contain the latter, and the decoction the former; a plausible, but erroneous idea, since both of them were carried off by the first water.

A much better method, and one we can recommend from experience, is to divide the coffee into 2 parts. Boil the first portion in the coffee-pot for 4 or 5 minutes, then add the other portion, and allow it to infuse slowly for about 10 minutes, the coffee-pot lid being kept well closed. This gives a coffee possessing a flavour which even the French cannot excel.

Coffee, Essence of. A highly concentrated infusion of coffee, prepared by percolation with boiling water, gently and quickly evaporated to about ⁄3rd or ⁄4th of its bulk, and mixed with a thick aqueous extract of chicory and syrup of burnt sugar, so as to give the whole the consistence of treacle. The proportions of the dry ingredients should be—coffee, 4 parts; chicory, 2 parts; burnt sugar (caramel) 1 part. It should be kept in well-corked bottles in a cool place. This preparation is very convenient for making extemporaneous coffee; but the beverage so made, though superior to much of that sold at coffee-houses, is inferior in flavour, aroma, and piquancy, to that we are accustomed to drink at home. Much of the so-called ‘Essence of Coffee’ is simply treacle and burnt sugar, flavoured with coffee.

Coffee, Searle’s Patent. This is prepared by mixing condensed milk with a very concentrated essence of coffee and evaporating at a low temperature (in vacuo, if possible), until the mixture acquires the consistence of a syrup (coffee syrup), paste (coffee paste), or candy (coffee candy). The last may be powdered (coffee powder, dry essence of coffee).

Coffee, Substitutes for. These are numerous, but are now seldom employed, owing to the cheapness of the genuine article, and the stringency of the revenue laws. Among the principal are the following:—

1. Coffee, Acorn. From acorns deprived of their shells, husked, dried, and roasted.

2. Coffee, Bean. Horse-beans roasted along with a little honey or sugar.

3. Coffee, Beet-root. From the yellow beet-root, sliced, dried in a kiln or oven, and ground with a little coffee.

4. Coffee, Dandelion. From dandelion roots, sliced, dried, roasted, and ground with a little caramel.

5. Coffee, German. Syn. Succory c., Chicory c. From chicory or succory. Used both for foreign coffee, and to adulterate it.

Obs. All the above are roasted, before grinding them, with a little fat or lard. Those which are larger than coffee-berries are cut into small slices before being roasted. They possess none of the exhilarating properties or medicinal virtues of foreign coffee.

COINS. See Medals and Electrotype.

COKE. Charred or carbonised coal. The principle of its manufacture is similar to that of charcoal. There are three varieties of coke:—

1. Kiln-made coke; STIFLED COKE. Made by burning pit-coal in a pile, kiln, or stove. It has a dull-black colour, and produces an intense heat when used as fuel. By condensing the bituminous vapours which are given off during the process, about 3% of tar may be obtained from common coal, and from some strong coal, by careful treatment fully 10% of its weight. The screenings of dust coal, separated from the better kinds of bituminous coal, is the sort commonly used for making coke in ovens.

2. Gas coke; DISTILLED COKE. The cinder left in the gas retorts. Grey; produces a weak heat, insufficient to smelt iron.

3. Shale Coke; MINERAL CARBON. From bituminous shale, burnt in covered iron pots, in a similar way to that adopted for making bone-black; or in piles. Black and friable. Used to clarify liquids, but is vastly inferior to bone-black, and does not abstract the lime from syrups. See Fuel, Pit-coal, &c.

COLCHICIN′A. Syn. Col′chicine. Colchicia. A peculiar principle discovered by Gieger and Hesse in the seeds of the Colchicum autumnale or common meadow saffron. It also exists in the corms or bulbs.

Prep. Macerate the bruised seeds in boiling alcohol, add magnesia, to throw down the alkaloid, digest the precipitate in boiling alcohol, and filter. By cautious evaporation colchicine will be deposited, and maybe purified by re-solution and crystallisation in alcohol.

Prop., &c. Odourless; bitter; soluble in water and alcohol; form salts with the acids. It is very poisonous. ⁄10th of a grain, dissolved in spirit, killed a cat in 12 hours. It differs from veratria in being soluble in water and crystalline, and in the non-production of sneezing when cautiously applied to the nose. Strong oil of vitriol turns this alkaloid of a yellowish-brown; nitric acid turns it of a deep violet, passing into indigo-blue, green and yellow. It is not used in medicine.

COL′CHICUM. Syn. Mea′dow saf′fron; Colchicum autumnale (Linn.), L. The recent and dried corms or bulbs (colchici cormus), as well as the seeds (colchici semina), are official in the British Pharmacopœia. The corms are ordered to be dug up in the month of July, or before the autumnal bud has projected. The dry coatings having been torn off, cut the corms transversely in thin slices, and dry, at first with a gentle heat, but afterwards slowly increased to 150° Fahr.

Dose (of the corms), 2 to 8 or 9 gr.; (of the seeds), 2 to 7 gr., made into a pill or bolus with syrup or conserve; chiefly, as a specific in gout, to alleviate or check the paroxysm. This drug forms the base of almost all the advertised gout nostrums. It is, however, an active poison, and its administration requires care. “After all that has been said respecting colchicum in gout, and admitting that it rarely fails to allay pain and check a paroxysm, I would record my opinion that he who would wish to arrive at a good old age should eschew it as an ordinary remedy, and consider that he is drawing on his constitution for a temporary relief, with a certainty of becoming prematurely bankrupt in his vital energies.” (Collier.)

Antidotes. An emetic consisting of one scruple of sulphate of zinc dissolved in water, followed by a brisk dose of castor oil, then stimulants, and also charcoal.

COL′COTHAR. See Oxides of Iron.

COLD. Syn. Fri′gus, L. The privation of heat. The term is also applied to the sensation and effects which this privation produces.

When the body of an animal is immersed in an atmosphere at a temperature below the healthy standard, a sensation of coldness is experienced, produced by the passage of the caloric or heat of the body into the colder medium. If this extraction of caloric exceeds the quantity produced by the vital system, the temperature of the body decreases, until it sinks below the point at which the functions of life can be performed. This declination of the heat of the body is gradual; the extreme sensation of coldness changes into a disinclination for voluntary motion; next comes on drowsiness, followed by numbness and insensibility. At this point if the sufferer is not rescued, and remedial measures had recourse to, death inevitably and rapidly ensues.

The prevention of the effects of cold consists in the use of ample food and clothing proportioned to the inclemency of the weather, the exposure to be endured, and the habits of the wearer. The circulation of the blood should be promoted by active exercise, and any disposition to sleep shaken off by increased bodily exertion. The principal endeavour should be to keep the extremities and chest warm, as, if this can be accomplished, no danger need be feared.

In cases of asphyxia produced by intense cold, the patient should be laid in a room remote from the fire, and bathed with cold salt-and-water, or water to which some brandy or vinegar has been added; after which the body should be wiped dry, and friction assiduously applied by the hands of the attendants (warmed); as many operating at once as can conveniently do so. Gentle stimulants should be administered by the mouth, and the bowels excited by some mild, stimulating clyster. The lungs should also be inflated, and an effort made to re-establish the respiration. As soon as symptoms of returning animation are evinced, and the breathing and circulation restored, the patient should be laid in a bed between blankets, and a little wine-and-water administered, and perspiration promoted by heaping an ample quantity of clothing on the bed. Should the patient have suffered from hunger as well as cold, the appetite may be appeased by the administration of a limited quantity of light food, taking especial care to avoid excess, or anything indigestible or exciting, &c. See Asphyxia, Bronchitis, Catarrh, &c.

COLD CREAM. A snow-white, bland ointment, about the consistence of good lard, and an admirable substitute for that excipient where expense is no object, especially for applications about the face. It is commonly sold as a lip-salve and as a healing application to abraded and chapped surfaces generally. The ordinary receipts are given under the head of Cosmetic Cerate (which see). The following produces a superior article.

Prep. (Dr L. Turnbull.) From white wax, 1 oz.; oil of almonds, 4 oz.; rose-water, 2 oz.; borax, ⁄2 dr.; oil of roses, 5 drops. Melt, and dissolve the wax in the oil of almonds by a gentle heat; dissolve the borax in the rose-water, which is then to be warmed a little and added to the heated oil; lastly, add the oil of roses, stirred.

COL′IC. Syn. Col′ica, L. The belly-ache or gripes. The name is popularly given to all severe griping abdominal pains, without reference to the cause. There are several varieties of this disease, as noticed below.

Colic, Accident′al. Produced by improper food, and poisons. The treatment may be similar to that recommended for bilious or flatulent colic.

Colic, Bil′ious. In this variety the pain is intermittent and transient, accompanied by constipation, nausea, and vomiting. The fæces, if any, are bilious, dark-coloured, and offensive. The common remedies are, a full dose of blue pill, calomel, colocynth, or aloes, followed by a sufficient quantity of Epsom salts or Glauber’s salts. Warm fomentations are also serviceable.

Colic, Flat′ulent. Marked by constipation, and the irregular distension of the bowels by gas, accompanied by a rumbling noise, &c. It is commonly produced by the use of indigestible vegetables and slops. The remedies are, a full dose of tincture of rhubarb combined with a few drops of essence of peppermint. If this does not afford relief, an Abernethy pill may be taken, washed down with a glass of any cordial water, as peppermint, cinnamon, or caraway. When the pain is extreme, warm fomentations to the belly, or a carminative clyster, will generally give relief. The Editor has found castor oil and Collis Browne’s chlorodyne of great benefit in this complaint.

Colic, Paint′er’s. Syn. Plumb′er’s colic, Devonshire c., Lead c.; Col′ica picto′num, L. The dry belly-ache. It is marked by obstinate costiveness, acrid bilious vomitings, violent pains about the region of the navel, convulsive spasms in the intestines, and a tendency to paralysis in the extremities. It is most prevalent in the cider counties, and amongst persons exposed to the fumes of lead. The remedies are the same as for the spasmodic variety. Should these fail, after the bowels have been thoroughly evacuated, small doses of camphor and opium may be administered, and sulphuric beer or sweetened water very slightly acidulated with sulphuric acid, had recourse to as a beverage. Mr Benson, the managing director of the British White-lead Works at Birmingham, says:—“Although during several weeks after the addition of the sulphuric acid to the treacle beer, drank at the works, little advantage seemed to be derived, yet the cases of lead colic became gradually less frequent, and since October of that year, or during a period of fifteen months, not a single case of lead colic has occurred amongst the people.” (‘Lancet.’) See Beer, Sulphuric Acid, and Sulphuric Acid.

Colic, Spasmod′ic. Marked by a fluctuating pain about the navel, which goes away and returns by starts, often leaving the patient for some time. The belly is usually soft, and the intestines may often be felt in lumps, which move about under the hand, or are wholly absent for a time. It is unaccompanied by flatulency. The remedies are warm fomentations, warm clysters, and carminatives, accompanied by small doses of camphor and opium.

Colic, Stercora′ceous. Marked by severe griping pains and constipation of the bowels. The remedies are powerful cathartics, as full doses of calomel, aloes, colocynth, jalap, &c., followed by purgative salts, as sulphate of magnesia, or sulphate of soda.

Colic in Horses. First give the horse a sharp trot, and apply friction over the belly, and follow this up with a drench of warm gruel to which has been added a glass or two of whisky or gin. Should these fail to give relief, let 4 dr. of aloes be rubbed down in a pint of hot water, and when the mixture becomes cool enough, add from thirty to sixty drops of strong solution of ammonia. Where the spasms and distress continue severe, and with little intermission, the physic may be followed in an hour with 2 dr. of tincture of aconite, given with an ounce of spirit of chloroform, in a little water, and repeated every hour; soap and water clysters should be administered every half hour, and friction and hot fomentations applied to the abdomen.

COLLO′DION. Syn. Collo′dium, L., B. P. A viscid fluid formed by dissolving pyroxylin (Schönbein’s gun-cotton) in a mixture of ether and alcohol. In surgery it is used in its natural state, and combined with certain elastic and medicinal substances. In photography it is used in combination with agents that render it sensitive to the action of light.

Collodion. Syn. Plain collodion. The following are the best methods of preparing plain collodion for surgical purposes:—

Prep. 1. (Ph. U. S.) Nitrate of potassa, in powder, 10 oz.; sulphuric acid, 8⁄2 fl. oz.; triturate together in a wedgwood mortar until uniformly mixed; then add of fine carded cotton (free from impurities), ⁄2 oz.; and by means of the pestle or a glass rod, saturate it thoroughly with the liquor for a period of about 3 or 4 minutes; next transfer the cotton to a vessel containing water, and wash it in successive portions of pure water, with agitation and pressure, until the washings cease to affect litmus paper or a solution of chloride of barium; it is then to be spread out and dried by a very gentle heat, and dissolved by agitation in a stoppered bottle with rectified sulphuric ether, 1 quart, to which rectified spirit (alcohol), 1 fl. oz., has been previously added.

2. (Mialhe.) Nitrate of potassa, 40 parts; concentrated sulphuric acid, 60 parts; carded cotton, 2 parts; proceed as last until the dry cotton is obtained, then take of the prepared cotton, 8 parts; rectified sulphuric ether, 125 parts; mix in a well-stoppered bottle, and agitate it for some minutes; then add gradually, rectified alcohol, 1 part; and continue to shake until the whole of the liquid acquires a syrupy consistency. It may be now passed through a cloth; but a better way to prevent loss is to let it repose for a few days, and then decant the clear portion.

3. (Lauras.) This process only differs from No. 2 in the following particulars:—The cotton is immersed for 12 minutes, then rinsed 2 or 3 times in cold water, and afterwards immersed in a solution of carbonate of potassa, 4 parts, and water, 200 parts. Lastly, it is plunged again into simple water, and dried at a temperature of 77° to 86° Fahr.

4. (B. P.) Pyroxylin, 1 part; rectified spirit, 12 parts; ether, 36 parts; mix the ether and spirit, and add the pyroxylin. Keep in a well-corked bottle.

5. (Parrish.) Thoroughly saturate clean carded cotton, ⁄2 oz., with fuming nitric acid and sulphuric acid, of each 4 fl. oz., previously mixed and allowed to become cool; macerate for 12 hours; wash the cotton in a large quantity of water; then free it from the water by successive washings in alcohol, and dissolve in ether, 3 pints.

Obs. For success in the manufacture of collodion it is absolutely necessary to avoid the presence of water. The ordinary commercial oil of vitriol, sp. gr. 1·84, may be used. Professor Procter, of Philadelphia, gives preference to the process with the mixed acids (No. 5), and directs that the cotton should be allowed to macerate for four days. In drying the cotton great care should be taken to prevent an explosion.

Uses, &c. In surgery plain collodion is employed as a dressing for wounds, and as a protection to abraded surfaces. On drying, it unites the former closely, and preserves the latter from the action of the air. It is impervious to water, and being transparent, it admits of the progress of the wound being inspected when necessary. Such is its adhesive power, that a piece of cloth cemented with it to the dry palm of the hand will support a weight of 25 to 30 lbs. The parts to which it is applied should be freed from moisture. See Collodions, Coloured, Elastic, Medicated and Vesicating (below).

Collodion, Blis′tering. See Vesicating Collodion.

Collodion, Col′oured. Syn. Collodium tinctum, L. Prep. (Cutan. Hosp.) Collodion, 2 oz.; palm oil, 1 dr.; alkanet root, q. s. to colour (say 15 gr.); digest and decant the clear. Colour bears a greater resemblance to the skin than that of common collodion, whilst it is more flexible; but it is weaker than the latter.

Collodion, Elas′tic. Prep. 1. (Lauras.) Heat together Venice turpentine, 2 parts; castor oil, 2 parts; and white wax, 2 parts; add sulphuric ether, 6 parts; and mix all with the product of No. 3 (above), that is, to the collodion formed with 8 parts of prepared cotton, 125 ether, and 8 alcohol.

2. (C. S. Rand.) Dissolve prepared cotton (No. 5, above), 2 dr., in sulphuric ether, 5 fl. oz.; then add, Venice turpentine, 2 dr., and complete the solution by slight agitation.

Obs. The collodion made by either of the above processes, when applied to the skin, forms a transparent pellicle, more pliable and more difficult to remove than that of ordinary collodion.

Collodion, Flexible. Collodion Flexile. (B. P.) Mix collodion (B. P.), 6 fl. oz., with Canada balsam, 120 gr.; and castor oil, 1 fl. dr., and keep in a well-corked bottle.

Collodion, Hemostatic. Collodion, 10 parts; carbolic acid, 1 part; tannic acid, ⁄2 part; benzoic acid, ⁄2 part; all by weight. To be applied with a pencil brush.

Collodion, Iodised. This may be made at one operation; it should be kept two days before being used, but is less reliable if kept for any length of time than the sensitised collodion described below. It is made as follows:—Place 16 grains of gun-cotton in a bottle, add 18 grains of iodide of cadmium in powder, 6 grains of bromide of cadmium in powder, and 1⁄2 oz. of spirits of wine (sp. gr. 0·805). Shake the bottle until the iodide and bromide are dissolved, then add 3 oz. of ether, sp. gr. 0·720, and shake until the cotton is dissolved. After settling for twenty-four hours, decant the clear portion into small well-stoppered bottles.

Collodion, Med′icated. It has been proposed to medicate collodion in several ways, but the practice has not found much favour with the medical profession. The following preparations have been described:—

Collodion, Aconite. From aconite root, by a similar formula to that of Belladonna c. (below).

Collodion, Belladonna. Prep. Macerate select belladonna leaves, powdered, 8 oz., in ether, 12 fl. oz., with alcohol (95%), 4 fl. oz., for six hours. Pack in a percolator, and pour en alcohol till a pint of tincture is obtained; in this dissolve pyroxylin (gun-cotton), 1 dr., and Canada balsam, ⁄2 oz. Used as a substitute for BELLADONNA PLASTER.

Collodion, Cantharidin. See Collodion, Vesicating.

Collodion, Iodine. Prep. Dissolve iodine and Canada balsam, of each ⁄2 oz., in collodion, 1 pint. Used as a substitute for IODINE OINTMENT.

Collodion, Morphia. (L′Union Medicale.) Dissolve 1 part of hydrochlorate of morphia in 30 parts of flexible collodion, and apply with a camel-hair brush.

Collodion, Photograph′ic. 1. There are so many methods adopted for preparing photographic collodion, that a large volume might be filled with notices of them. We have retained Mr Hardwich’s forms, which were formerly much esteemed by practical photographers, and appended to them modern formulæ which are now, we believe, in much greater demand, and for which we are indebted to Mr Ernest Spon’s valuable book ‘Workshop Receipts.’

2. Pyroxylin, and iodide of cadmium, or ammonium, of each 15 gr.; ether, 3⁄2 oz.; alcohol, 1⁄2 oz. Place the two first in a dry bottle, then pour on the spirits of wine, shake the mixture well, then add the ether, shake again and let it stand for 12 hours. Decant the clear portion into a wide-mouthed bottle, keep well stoppered, and in the dark. Avoid shaking the bottle when about to use the collodion, and never quite use all the bottle contains, as the sediment which will accumulate at the bottom would spoil the picture. The preparation of a sensitive collodion, whether positive or negative, includes three distinct operations, namely, the formation of the pyroxylin or gun-cotton, the conversion of this into plain collodion, and the final process of iodising the collodion.

Collodion, Plain. Mix in a bottle gun-cotton, 450 gr.; ether, 25 oz.; spirits of wine, 7 oz. Shake these well together, and leave to settle several days. Keep well corked.

Collodion, Pos′itive. (Hardwich.) To form the PYROXYLIN:—Take sulphuric acid, sp. gr. 1·845, at 60° Fahr., 12 fl. oz.; nitric acid, sp. gr. 1·45, at 60°, 12 fl. oz.; water, 3⁄2 fl. oz.; mix, and allow the temperature to fall to 140°; then immerse cotton, 300 grains. (If the cotton is found to gelatinise or dissolve in the acid mixture, the quantity of water is too great, and may be reduced to 3 fl. oz.) The cotton should be well pulled out in pieces, weighing about 30 grains each; and should be left in the acid for about 8 minutes, the vessel being covered over. It is taken out with a glass spatula, squeezed to remove acid, washed for at least 24 hours by a stream of water, then squeezed in a cloth, and pulled out to dry. To form the PLAIN COLLODION:—Shake up the dry pyroxylin, 48 grains, with alcohol, sp. gr. ·805, 1⁄2 fl. oz., and then add ether, sp. gr. ·725, 4⁄2 fl. oz. The solution should be allowed to rest for a week or ten days, when the clear fluid should be decanted from the sediment. To prepare the IODISING SOLUTION:—Take of iodide of ammonium, 1⁄2 dr.; iodide of cadmium, 1⁄2 dr.; bromide of ammonium, 40 grains; powder, and dissolve in alcohol, sp. gr. ·805 to ·816, 10 fl. oz. The collodion is iodised by adding the solution to it in the proportion of 1 part solution to 3 parts collodion. The iodised collodion should be kept for at least six weeks before using. If required for immediate use, add a few drops of an alcoholic solution of iodine, formed by dissolving 5 grains of iodine in 1 fl. oz. of alcohol.

Obs. Mr Hardwich recommends that the cotton, before being converted into pyroxylin, should be cleansed by boiling for two hours in a solution of caustic potassa (2 oz. to the gallon), and by being afterwards repeatedly washed and dried. The purest nitric acid, sp. gr. 1·45, should be employed, but the ordinary commercial sulphuric acid (oil of vitriol) is sufficiently pure for use. To purify the ETHER and to get rid of a certain ozonised principle which would decompose the iodising solution, Mr Hardwich recommends the following process:—Take the best washed ether of commerce and agitate it thoroughly with a small portion of dilute sulphuric acid, and then introduce it into a retort, and distil over one third. The alcohol used is of the strength of that sold for absolute alcohol; it should be pure.

Collodion, Neg′ative. (Hardwich.) To form the PYROXYLIN:—Take of sulphuric acid, sp. gr. 1·845, at 60°, 18 fl. oz.; nitric acid, sp. gr. 1·475, at 60°, 6 fl. oz.; water, 5⁄4 fl. oz.; cotton, 300 grains. Mix, and allow the temperature to fall to 150° Fahr. The weight of the pyroxylin ought to be 375 grains. To form the PLAIN COLLODION:—Take alcohol, sp. gr. ·806, ⁄2 gallon; ether, sp. gr. ·725, 1 gall.; pyroxylin, 1900 grains. Saturate the pyroxylin with the alcohol, then pour in half a gallon of the ether, agitate for 3 or 4 minutes, and repeat the process in adding the remainder. Decant the clear liquid from the sediment after a week or ten days’ rest. The following forms for IODISING SOLUTIONS are recommended:—a. (Potassium Iodiser.) Iodide of potassium, 135 grains; alcohol, sp. gr. ·816, 10 fl. oz. Powder and dissolve in the alcohol, previously heated to 140°.—b. (Cadmium Iodiser.) Iodide of cadmium, 170 grains; alcohol, sp. gr. ·816, 10 fl. oz. Dissolve in the cold, and filter.—c. (Bromo-iodiser.) Bromide of ammonium, 40 grains; iodide of ammonium, 90 grains; iodide of cadmium, 90 grains; alcohol, sp. gr. ·816, 10 fl. oz. Pulverise and dissolve in the cold. To sensitise the collodion, add to three parts one part of either a, b, or c.

Obs. Most of the practical directions given under the head of POSITIVE COLLODION apply equally to NEGATIVE COLLODION. Nothing but patient and intelligent practice will ever lead to success in preparing collodion for photographic purposes. Although formulæ of undoubted excellence may be used, it continually happens that the results are entirely nugatory from some trifling cause. See Photography.

Collodion, Sensitised. Add to 1 oz. of the plain collodion 6 drams of spirits of wine; 1⁄4 oz. of ether; and 3 drams of iodide and bromide solution (see below). Shake the bottle well; the mixture is then ready, but is improved by being kept four or five hours before using. In hot weather a little more alcohol and less ether; in very cold weather more ether and less alcohol must be used. As sensitised collodion does not keep well, it is better not to mix the plain collodion and the iodide and bromide solution until shortly before required for use.

Iodide and Bromide Solution. Iodide of cadmium 154 grains; bromide of cadmium 54 grains; spirits of wine, 3⁄2 ounces. Pound the iodide and bromide very fine in a mortar, adding the spirit gradually; when the iodide and bromide are dissolved, pass the solution through a filter paper into a bottle. Must be kept in a closely-stoppered bottle.

Collodion, Styptic. Syn. Styptic colloid. (Dr Richardson.) To a saturated solution of tannic acid in alcohol and ether, in equal parts, add as much pyroxylin as the liquid will dissolve.

Collodion, Ves′icating. Syn. Blis′tering collodion, Canthar′idin c.; Collo′dium ves′icans, L. Prep. 1. (Tichborne.) Coarsely powdered cantharides, 6 oz., are placed loosely in a displacement apparatus (provided with a tap to regulate the flow), and treated with ether from methylated spirit, 13 fl. oz., and glacial acetic acid, 2 fl. oz., previously mixed together. After the fluid has passed through, it will be found that the débris has retained by absorption 7 fl. oz., which must be displaced by the gradual addition of methylated spirits of wine, 7 fl. oz. If properly managed, there is not the least danger of the admixture of the spirits with the percolated menstruum, as the animal substance of the flies swells considerably under the prolonged influence of the spirits of wine, so that the same bulk will be insufficient to quite displace the ether. The ethereal solution should be made to measure exactly 15 fl. oz. with a little spirit, and may then be converted into a collodion by the addition of pyroxylin, ⁄2 oz.

Obs. The glacial acid plays a double part in this preparation. It dissolves the cantharidin, and at the same time gives to the collodion film the essential property of porosity. Ordinary collodion is useless as an excipient, for it produces a tough and contractile film, which really screens the skin from the action of the greater part of the blistering material.

2. (Ilisch.) Cantharidin, 15 gr.; pyroxylin, 20 gr.; rectified ether, 1⁄2 oz.; acetic ether, ⁄2 oz.; dissolve.

3. (Œttinger.) Ether of cantharides and collodion, equal parts.

Use. Vesicating collodion is used as an irritant. No. 1 was introduced in 1862, and has many advantages over the other two. Mr Tichborne thus described the most effectual method of using it in the ‘Pharm. Journ,’:—“The part upon which the blister is to be raised should be painted with the vesicant to the desired extent, bearing in mind that the blister produced always extends to about one tenth of an inch beyond the margin of the space covered. Care should be taken to give a coating of considerable thickness, and to ensure this result the brush should be passed over and over again, until about ⁄2 dr. has been used to the square inch, or less when operating upon a tender epidermis. It is desirable to place over the intended blister a piece of oil silk, or, what is still better, a piece of sheet gutta percha, somewhat larger than the surface painted, as this will stop the exhalations of the skin, and so render it moist and permeable. In ten minutes, or a quarter of an hour if the cuticle is hard, the collodion should be wiped off with a little cotton-wool moistened with ether, when the blister will almost instantly rise.”

COL′LOID. See Dialysis.

COLLYR′IUM. [L.] In medicine and pharmacy, a topical remedy for diseases of the eye. Formerly the term collyrium was applied to any medicament employed to restrain defluxions.

Collyr′ium, Dry. Syn. Eye powder; Collyr′ium sic′cum, L. Prep. 1. (Dupuytren.) White sugar, 1 dr.; red oxide of mercury, 10 gr.; oxide of zinc, 20 gr.; mix.

2. (Lagneau.) Sugar candy, 2 parts; nitrate of potassa, 1 part.

3. (Falconer.) Chloride of barium, 1 gr.; sugar candy, 1 dr.

4. (Radius.) Calomel and white sugar, of each ⁄2 dr.; opium, 10 gr.

5. (Recamier.) Oxide of zinc and sugar candy, equal parts.

6. (Velpeau.) Trisnitrate of bismuth and sugar candy, equal parts.

7. (Wiseman.) Acetate of soda, 10 gr.; powdered opium, 1 gr.; sugar candy, ⁄2 dr.

Obs. It is absolutely necessary that the ingredients in the above preparations should be reduced to an impalpable powder by careful trituration in a wedgwood mortar. For use, a small pinch is placed in a quill or straw, and blown into the eye previously opened with the fingers. On the whole, they may be regarded as unnecessary preparations, and are unsafe, except in skilful hands.

Collyrium, Liq′uid. See Waters (Eye).

Collyrium, Unct′uous. See Ointments (Eye).

COL′OCYNTH (sĭnth). Syn. Colocynth pulp., Colocynthidis pulpa, B. P. Bit′ter ap′ple, Bitter gourd, Bitter cu′cumber, Peeled colocynth; Coloquint′ida, Colocynth′is (B. P.), L. The decorticated fruit or pulp of the Citrellus Colocynthis (Schrad.—Ph. L.), or Cucumis Colocynthis (Linn.—Ph. E. & D.). It is an acrid, drastic purge and hydragogue, and cannot be given alone with safety; but, in combination with other substances, it forms some of our most useful cathartic medicines.

COLOCYNTH′IN. Syn. Colocynth′ium, L. The bitter, purgative principle of colocynth.

COL′OPHENE. Formed by distilling oil of turpentine with concentrated sulphuric acid. A colourless, viscid, oily liquid; with a high boiling-point; and exhibiting a bluish tint by reflected light.

COL′OPHONY. See Resin.

COLORADO BEETLE. Syn. Doryphera decemlineata. The Colorado potato beetle belongs to the family Chrysomelidæ, and is a native of the eastern slopes of the Rocky Mountains. It measures nearly half an inch in length, and has a tawny or yellowish cream-coloured body, darkly spotted; with wing cases which are marked with ten black longitudinal stripes. It has been gradually migrating eastward toward the more cultivated lands of the Northern states, until it has reached the Atlantic coast. It is now found over all the central and northern parts of the United States east of the Rocky Mountains, as well as throughout Canada, on the potato crops of all of which regions it has committed incalculable ravages. The leaves and stalks are the parts of the potato plant principally attacked; the depredators being, for the most part, the larvæ, of which three broods are said to be produced annually.

In America, we believe, the only means of destroying these insects as well as their eggs and larvæ consists in the application to the plant of the highly poisonous and dangerous pigment, Scheele’s green, a hydrated arsenite of copper. M. Girard recommends in preference to the arsenical salt a liberal use of sulpho-carbonate of potash.

COLOUR BLINDNESS. Syn. Dal′tonism. A curious defect of vision, from which the eye is incapable of distinguishing colours. It is of three kinds:—1. An inability to distinguish any colour properly so called, the person being only able to distinguish white and black, light and shade. 2. An inability to distinguish between the primary colours, red, blue, and yellow, or between these and the secondary or tertiary hues, such as green, purple, orange, and brown. 3. An inability to distinguish nicer shades and hues, as greys and neutral tints. The first form is rare; the second and third are common. Dr George Wilson found that of 1154 persons examined by him in Edinburgh, 65, or 1 in 177, were colour blind; of these, 21 confounded red with green, 19 brown with green, and 25 blue with green.

COL′OURING. Syn. Brandy colouring, Brewer’s c., Spirit c. Car′amel; Essen′tia bi′na, L. Prep. Brown sugar is melted in an iron vessel over the fire until it grows black and bitter, stirring it well all the time, after which water is added, and it is boiled to a syrup. In the making of brandy colouring white sugar is more frequently used.

Obs. Some persons use lime-water to dissolve the burnt sugar. Care must be taken not to overburn it, as a greater quantity is thereby rendered insoluble. The heat should not exceed 430°, nor be less than about 400° Fahr. The process, for nice experiments, is best conducted in a bath of melted tin, to which a little bismuth has been added to reduce its melting-point to about 435°; a little powdered resin or charcoal or a little oil being put upon the surface of the metal, to prevent the oxidisement of the alloy. See Caramel.

COL′OURS. White light from the sun is of a compound nature, and may be decomposed into rays of different colours. Newton distinguished seven PRIMITIVE COLOURS, namely, violet, indigo, blue, green, yellow, orange, and red. Sir D. Brewster is disposed to think that four of these colours are really compound, and that three, namely, blue, yellow, and red, alone deserve the name of primitive. The colours of natural objects are supposed to result from the power possessed by their surfaces of absorbing some of the coloured rays of light, while they reflect or transmit, as the case may be, the remainder of the rays. Thus, an object appears red because it absorbs or causes to disappear the yellow and blue rays composing the white light by which it is illuminated. Black and white are not colours, strictly speaking.

A body is said to be black when it absorbs or quenches a large proportion of all the rays of white light falling upon it. A body is said to be white when it receives the white light, and reflects all the rays with moderate strength. Grey may be regarded as a luminous black or dark white. The names given to colours are far from being satisfactory, for although many thousand shades may be distinguished by a practised eye, it is a question whether there are fifty names which would convey the same idea of shade to any ten colourists in the world. The names taken from natural coloured objects, as indigo, violet, orange, lilac, amber, emerald, &c., are the least objectionable. M. Chevreul has devised an ingenious system of naming and classifying colours. He employs only 6 fundamental names, which are those of the three elementary colours, red, yellow, and blue; and of the three secondary colours, orange, green, and violet. By the direct union of the elementary and secondary colours, 6 tertiary colours are formed. He arranges the twelve colours in a circle, like the spokes of a wheel, commencing with the red, and going to the right, thus:—Red, red-orange, orange, yellow-orange, yellow, yellow-green, green, blue-green, blue, blue-violet, violet, red-violet. The chromatic circle is completed by placing 5 shades between the red and red-orange, 5 between the red-orange and orange; and so on between each of the other couples. This chromatic circle of 72 colours is not imaginary, but actually exists, composed of dyed wools. The shades are distinguished by numbers; thus there are red, 1 red, 2 red, 3 red, 4 red, and 5 red, &c. Each of the 72 shades has, moreover, 20 different degrees of depth, from the lightest that can be discerned from pure white to the most intense depth, approaching to brown and black. These degrees of depth are called tones or tints. The addition of these tones to the chromatic circle brings up the number of tints to 1440. To indicate any one of these tints we have merely to write the number of the shade, and after it the number of the tone, as, for example, 3 blue-violet, 13 tone. By mixing each of the 1440 tints with grey or black, so as to darken it in different degrees, a total of 14,440 colours may be defined. This part of the system is generally regarded as unnecessary. Mr O′Neill, in his valuable ‘Dictionary of Calico Printing and Dyeing’ (to which work we refer the reader for a full account of Chevreul’s classification), gives a long list of colours and coloured bodies, which are pretty well defined in common language with the names of the colours, according to this ingenious system. We select from this list the following examples:—

Amber in mass = 2 orange, 12 tone.

Amethyst = 5 blue-violet, from 3 to 16 tone.

Blood, ox = 1 red, 13 and 14 tones.

Butter = yellow-orange, 2 to 3 tone.

Carrot = orange, 7 tone.

Chocolate in cake = 5 orange, 18 tone.

Emerald = 2 green, 11 tone.

Green, apple = 4 yellow-green, 8 tone.

Isabelle = 1 yellow-orange.

Mauve = 3 violet, 8 tone.

Red-lead = yellow-orange, 20 tone.

Ruby = red, 11 tone.

Yellow, canary = 1 yellow, 6 tone.

For notices of Dyes, Pigments, &c., refer to the principal colours.

Colours, Cake. Syn. Artists’ Colours. These are made by grinding by means of a glass muller and a slab, the respective pigments previously reduced to powder, into a smooth paste with equal parts of isinglass size, and thin gum water. The paste is then compressed into squares as tightly as possible, and dried with a very gentle heat. Old crumbling cake colours should be powdered very finely in a biscuit-ware mortar, sifted through fine muslin, and ground up as above, the gum water being omitted. The powders rubbed up with honey to the consistence of cream constitute moist colours.

Colours, Complement′ary. Syn. Accident′al Colours. Colours are said to be complementary to each other which, by blending together, produce the perception of whiteness. According to Mayer, all colours are produced by the admixture of red, yellow, and blue light, in certain proportions; and by intercepting either one or more of these coloured rays in a beam of light, those which meet the eye will consist of the remaining coloured rays of the spectrum. Thus, by intercepting the red rays in a beam of white light, the remaining yellow and blue rays will produce a green colour; by intercepting the blue rays, the remaining yellow and red will give an orange; and so on of other cases; so that red and green, blue and orange, are COMPLEMENTARY COLOURS. If we look for some time, with one eye, on a bright-coloured object, as a wafer, placed on a piece of paper, and subsequently turn the same eye to another part of the paper, a similarly shaped spot or mark will be seen, but the colour will vary, though it will be always the same under like circumstances. Thus, if the original spot or wafer be of a red colour, the imaginary one will be green; if black, it will be white; the imaginary colour being always complementary of that first gazed upon. The colour so perceived is often called an ACCIDENTAL COLOUR, to distinguish it from the real colour. It is a general maxim in design that “colours look brightest when near their complementary colours.”

Colours, Drug′gists’ Show. See Show Bottles.

Colours, Flame. See Fires (Coloured).

COLTS′FOOT. This popular herb is the Tussilago farfara of Linnæus. It is a demulcent bitter, and is slightly stomachic and tonic. It is much esteemed by the lower classes in coughs, shortness of breath, and other affections of the chest. The leaves form the basis of most of the British herb tobaccos, and have been recommended to be smoked in asthma and difficulty of breathing.—Dose. One or two wine-glassfuls of the tea or decoction (1 oz. to the pint) ad libitum.

COLUM′BIC ACID. See Tantalic Acid.

COLUM′BIUM. See Tantalum.

COMA. A deep, heavy sleep, from which the patient cannot be aroused. See Apoplexy.

COMACHROME FOR DYEING THE HAIR BLACK. Nitrate of silver solution, with pyrogallic acid. (Reveil).

COMBINA′TION. In chemistry, the union of dissimilar substances. The great general laws which regulate all chemical combinations admit of being laid down in a manner at once simple and concise. The laws of COMBINATION BY WEIGHT are as follows:

“1. All chemical compounds are definite in their nature, the ratio of their elements being constant.

“2. When any body is capable of uniting with a second in several proportions, these proportions bear a simple relation to each other.

“3. If a body, A, unite with other bodies, B, C, D, the quantities of B, C, D, which unite with A, represent the relations in which they unite among themselves, in the event of union taking place.

“4. The combining quantity of a compound is the sum of the combining quantities of its components.” (Fownes.)

There is a remarkable relation between the specific gravity of a body in the gaseous state and its chemical equivalent or combining proportion—a relation of such a kind that quantities by weight of the various gases, expressed by their equivalents, or, in other words, quantities by weight which combine occupy, under similar circumstances of pressure and temperature, either equal volumes or volumes bearing a simple proportion to each other. This relation accounts for the law of COMBINATION BY VOLUME discovered by Gay-Lussac, and thus expressed:—

When gases combine, chemical union invariably takes place, either between equal volumes or between volumes which bear a simple relation to each other.

Gerhardt assumes that equal volumes of the elementary gases and vapours, when compared under similar conditions of pressure and temperature, contain the same number of atoms. Consult the chemical works of Fownes, Roscoe, Watts, &c. See Affinity, Atomic Theory, Equivalents, &c.

COMPOUND CHINESE TABLET OF ALABASTER (John Irvine). A cosmetic powder for the skin. It consists of chalk, free from injurious metals. (Chandler).

Compound Chinese Tablet of Alabaster (Shand). Identical in use and composition with the last-mentioned powder.

COMPOUND SUGAR-COATED MAY-APPLE PILLS (Dr Scott). Recommended as “antibilious, cathartic, chemical family pills.” Sugar-coated pills, consisting of bitter extract, powdered podophyllum root, rhubarb, jalap, and pepper. (Hager).

COMPRESSES DESINFECTANTES DE LE PERDRIEL. Charcoal powder incorporated with paper.

CONCENTRATED CASTOR OIL in Capsules of Gelatin (Taylor). 24 gelatin capsules filled with castor oil, containing ·5 per cent. of croton oil. (Hager).

CONCENTRA′TION. The volatilisation of part of a liquid in order to increase the strength of the remainder. The operation can only be performed on solutions of substances of greater fixity than the menstrua in which they are dissolved. Many of the liquid acids, solutions of the alkalies, &c., are concentrated by distilling off their water.

In pharmacy, the term CONCENTRATED is commonly applied to any liquid preparation possessing more than the usual strength. Thus, we have concentrated infusions, decoctions, liquors, solutions, tinctures, and essences, most of which are made of 8 times the common strength. This is generally effected by using 8 times the usual quantity of the ingredients, with a given portion of the menstruum, and operating by digestion and percolation; the latter being generally adopted when the articles are bulky. When the menstruum is water, a little spirit is added, to make the product keep. See Decoction, Infusion, &c.

CON′CRETE. A compact mass or cement, composed of pebbles, lime, and sand, employed in the foundations of buildings. The best proportions have been said to be—60 parts of coarse pebbles, 25 of rough sand, and 15 of lime; but Semple recommends 80 parts of pebbles, 40 parts of river sand, and only 10 parts of lime. The pebbles for concrete should not exceed about ⁄2 lb. each in weight.

CON′DIMENTS. Substances taken with the food, to season or improve its flavour, or to render it more wholesome or digestible. The principal condiments are COMMON SALT, VINEGAR, LEMON-JUICE, SPICES, AROMATIC HERBS, OIL, BUTTER, SUGAR, HONEY, and SAUCES. Most of these, in moderation, promote the appetite and digestion, but their excessive use tends to vitiate the gastric juice, and injure the stomach.

CONDY’S FLUID (from England). A weak solution of permanganate of soda. (Wittstein.)

CONFEC′TION. Syn. Confectio, L. Anything prepared with sugar; a sweetmeat, or candy. In medicine the name is commonly applied to substances, usually pulverulent, mixed up to the consistence of a soft electuary, with powdered sugar, syrup, or honey. In the ‘London Pharmacopœia’ (1836 and 1851) both CONSERVES and ELECTUARIES are included under this head, though there appears to be some little distinction between them.

In the preparation of confections all the dry ingredients should be reduced to very fine powder, and passed through a sieve, not coarser than 80 holes to the inch; and the pulps and syrups used to mix them up should be perfectly homogeneous, and of a proper consistence. The mixture should be intimate and complete, in order that the characteristic constituents may be equally distributed throughout the mass. The consistence of the newly made confection should be sufficiently solid to prevent a separation of the ingredients, and yet soft enough to allow of it being easily swallowed without previous mastication.

Confections should be preserved in stone jars covered with writing paper, and placed in a cool and not too dry a situation. Without this precaution they are apt to mould on the top. If at any time the mass ferments and swells up, the fermentative process may be arrested by placing the jar in a bath of boiling water, for an hour or two, or until the whole becomes pretty hot; when it should be removed from the heat, and stirred occasionally until cold. Should the sugar crystallise out of the confection, or ‘candy,’ as it is called, the same method may be followed. Or, the mass may be well rubbed in a mortar until the hard lumps of sugar are broken down and a uniform consistence again produced. On the large scale it may be passed through the mill.

As remedial agents, the officinal confections possess little value, and are chiefly used as vehicles for the administration of more active medicines. See Conserves and Electuaries.

Confection of Acorns. Syn. Confec′tio sem′inum quer′cus, L. Prep. (Bories.) Powdered acorns, 3 oz.; red coral and catechu, of each 1⁄2 oz.; confection of dog-rose, 10 oz.; syrup of red roses, q. s. to make a confection.—Dose, 1 dr., every 4 hours; in chronic diarrhœa, &c.

Confection of Almonds. Syn. Almond paste, Conserve of almonds; Confec′tio amyg′dalæ (Ph. L.), Conser′va amygdala′rum (Ph. E.), Confec′tio amygdala′′rum (Ph. D. 1826), L. Prep. (Ph. L.) Sweet almonds, 8 oz.; white sugar, 4 oz.; powdered gum Arabic, 1 oz.; macerate the almonds in cold water, then remove the skins, and beat them with the other ingredients until reduced to a smooth confection. The Ph. E. form is similar. See Powders, Compound Powder of Almond.

Uses, &c. To prepare EMULSION of MILK OF ALMONDS. A little of this paste or powder, triturated with a sufficient portion of water and strained through a piece of calico, forms emulsion of almonds. “This confection will keep longer sound if the almonds, first decorticated (blanched), dried, and rubbed into the finest powder, be mixed with the acacia and sugar, separately powdered, and the mixed ingredients be kept in a well-stoppered bottle.” (Ph. L.) The same effect may be arrived at by simply well drying the blanched almonds before mixing them with the gum and sugar. The addition of even a small quantity of water or syrup causes the confection “to become soon mouldy, or rancid, or both.” (Brande.)

Confection of Al′um. Syn. Confectio alu′minis, L. Prep. 1. (St. B. H.) Alum (in fine powder), 1 dr.; conserve of roses, 6 dr.

2. (Foy.) Alum, 1 dr.; conserve of roses, 1 oz.—Dose, 1 dr., 2 or 3 times a day; in lead colic, and as an astringent in diarrhœa and other affections.