A Cyclopædia of Practical Receipts, &c. Volume II (part 9)

Pills, Wordsell’s (Kaye’s). Prep. (Cooley.) Powdered aloes, gamboge, and ginger, equal parts; together with a very small quantity of diaphoretic antimony, beaten into a mass with either syrup or treacle, and divided into 2⁄2-gr. pills. “There are about 4⁄2 dozen pills in each 1s. 1⁄2d. box.” “The dose, as given in the directions, is from 2 to 8 pills (or even 10 to 12) daily.” (‘Anat. of Quackery.’) They frequently operate with great violence.

Pills, Wyndham’s (Lee’s). Prep. (Cooley.) Aloes and gamboge, of each (in powder) 3 oz.; Castile soap and extract of cow-parsnip, of each 1 oz.; nitre, ⁄2 oz. For 5-gr. pills. A powerful drastic cathartic.—Dose, 1 to 3 pills.

Pills of Zinc. See Pills of Oxide, Sulphate and Valerianate of Zinc, &c.

PILOCARPINE. Prep. Exhaust the leaves or bark of Jaborandi with 80% alcohol, to which hydrochloric acid has been added in the proportion of 8 grains per litre; distil and evaporate to the consistence of an extract. Redissolve the extract with a small quantity of distilled water and filter; treat with ammonia in slight excess, and a large quantity of chloroform. Distil off the chloroform, dissolve the residue in distilled water acidulated with hydrochloric acid, and filter. Treat afresh with chloroform and ammonia. The chloroformic solution is then shaken with water, to which hydrochloric acid is added, drop by drop, up to the quantity sufficient to saturate the pilocarpine. The foreign matters remain in the chloroform, and upon evaporation of the aqueous liquid the hydrochlorate is obtained, well crystallised, in long needles radiating from a common centre. The hydrochlorate dissolved in distilled water, and treated with ammonia and chloroform, yields the pilocarpine upon evaporation of the chloroform solution.

Pilocarpine appears under the form of a soft viscous substance; it is slightly soluble in water and very soluble in alcohol, ether and chloroform. It presents all the chemical characters of an alkaloid, and rotates the plane of polarized light strongly to the right. (Paris Pharmaceutical Society.)

PIMA′RIC ACID. A resin acid first obtained by Laurent from the turpentine of Pinus maritima (Bordeaux turpentine), by the action of hot alcohol.

PIMEN′TO. Syn. Allspice, Clove pepper, Jamaica p., Pimento berries; Pimenta (B. P., Ph. L., E., & E.), Piper caryophyllatum, P. Jamaicense, P. odoratum, PIMENTÆ BACCÆ, L. “The dried unripe berries of the allspice tree, Eugenia pimenta, from the West Indies”—B. P. “The immature fruit of Eugenia pimenta (Myrtus pimenta, Linn.)”—Ph. L. It possesses a mixed odour of cinnamon, cloves, and nutmegs, which, with its other properties, it for the most yields to alcohol, ether, and water. It is a stimulant and tonic, and is much esteemed as an adjuvant in medicines prescribed in dyspepsia, flatulence, gout, hysteria &c.; and also to cover the taste of disagreeable medicines.—Dose, 5 to 30 gr., bruised or in powder. See Essence, Oils (Volatile), Spirits, and Waters.

PIM′PLES. See Eruptions (Papular).

PINCH′BECK. A gold-like alloy of copper and zinc. See Dutch gold.

PINE APPLE. Syn. Ananas. The fruit of Ananassa sativa, a plant of the natural order Bromeliaceæ. It is astringent, esculent, and possesses a rich flavour and odour. In Europe it is chiefly used as a delicacy for the table; but in tropical climates it is said to be valuable in renal diseases. See Essence, &c.

PI′NEY TAL′LOW. Syn. Piney resin, P. dammar. An oleo-resinous substance obtained from the fruit of Vateria indica, a tree common in Malabar, by boiling it with water. It is intermediate between fat and wax, makes good soap and excellent candles. It melts at 98° Fahr. Sp. gr. ·9250 to ·9265.

PI′NIC ACID. The portion of common resin or colophony which is soluble in cold alcohol of sp. gr. ·833.

PINK. A well known shade of light red. The name is also applied to several pigments, consisting of whiting stained with liquid dyes. See Red and Yellow pigments, &c.

PINK DYE. Prep. From washed safflower, 2 oz.; salt of tartar, ⁄2 oz.; cold water, 1 quart; digest for 3 hours, express the liquor, and strain it. Used as a cosmetic, and to dye silk stockings, &c., of a rose colour. The colour is brought out by afterwards applying to, or passing the articles through, water soured with lemon juice. See Saucers (Pink).

PIP′ERIN. C17H19NO3. Syn. Piperina, Piperinum, L. Prep. (P. Cod.) Alcoholic extract of black pepper is treated with a weak solution of caustic potassa (1 to 100), and the residuum, after being washed with cold water, is dissolved in alcohol; the solution is next agitated with a little animal charcoal, and the filtrate is allowed to evaporate spontaneously; the product may be purified by the re-solution in alcohol and re-crystallisation.

Prop., &c. Colourless, or only slightly yellow; tasteless; inodorous; fusible; and crystallisable; insoluble in water; freely soluble in strong spirit, and in the acids; very feebly basic; a few definite compounds have, however, been obtained with difficulty; reddened by oil of vitriol. It has been much employed in Italy and on the Continent as a febrifuge.—Dose, 2 to 10 gr., frequently repeated, during the apyrexia of intermittents.

Obs. An assay for its piperin is the only certain method of testing the quality of either black or white pepper. For this purpose a weighted quantity of the sample is reduced to powder, and is exhausted with alcohol of the sp. gr. ·883; the mixed tinctures are then evaporated to an extract, which is treated as above. See Pepper.

PIPES. (In confectionery.) These are formed from any of the common lozenge-masses, by rolling them into cylinders of about the thickness of a goose-quill. They are frequently medicated.

PIPETTE. A graduated glass instrument, in frequent use in the chemical laboratory, for conveying a measured quantity of fluid from one vessel to another. The pipette mostly consists of a bulb, from each end of which proceeds a straight, slender hollow stem, communicating with the bulb, and varying in length with the capacity of the instrument. Thus constructed, the lower end of the pipette can be dipped into a vessel with a narrow and long neck, such as a flask, containing a fluid, the required volume of which can be removed from it. The pipette varies in capacity from 1 to 200 cubic centimètres.

Dr Fresenius gives the following directions for its use:—“To fill a pipette with the fluid which it is intended to transfer from one vessel to another, the lower part of the instrument is dipped into the fluid, and suction applied to the upper aperture, either direct with the lips or through a caoutchouc tube until the fluid in the pipette stands a little above the required mark; the upper, somewhat narrowed, ground orifice is then closed with the point of the index of the right hand, which to that end had always better be moistened a little, and holding the pipette in a perfectly vertical direction, the excess of over the quantity required is made to drop out by lifting the finger a little. When the fluid in the pipette has fallen to the required level, the drops which may happen to adhere to the outside of the pipette are carefully wiped off, and the contents of the tube are then fully transferred to the other vessel. In this process it is found that the fluid does not run out completely, but that a small portion of it remains adhering to the glass in the point of the pipette; after a time, as this becomes increased by other minute particles of fluid trickling down from the upper part of the tube, a drop gathers at the lower orifice, which may be allowed to fall from its own weight, or may be made to drop off by a slight shake; if, after this, the point of the pipette be laid against a moist portion of the inner side of the vessel, another minute portion of fluid will trickle out; and lastly, another trifling droplet or so may be got out by blowing into the pipette through the upper orifice. Now, supposing the operator follows no fixed rule in this respect, letting the fluid, for instance, in one operation simply run out, whilst in another operation he lets it drain afterwards, and in a third blows off the last particles of it from the pipette, it is evident that the respective quantities of fluid delivered in the several operations cannot be quite equal. I prefer in all cases the second method, viz. to lay the point of the pipette whilst draining finally against a moist portion of the inner side of the vessel, which I have always found to give the most accurate corresponding measurements.”

PISTA′CHIO NUTS. Syn. Pistacia nuts; Nuces pistaciæ, L. The kernels of the fruit of Piscatia vera (Linn.), one of the turpentine trees. They closely resemble almonds, but are sweeter, and form a green emulsion with water. Used in confectionery and perfumery, and also as a dessert fruit.

PITCH. Syn. Black pitch, Boiled p., Stone p., Wood p.; Pix (Ph. L.), Pix nigra, L. “A dry bitumen prepared from liquid pitch.” (Ph. L.) The residuum from boiling tar in an open iron pot, or in a still, until the volatile and liquid portion is driven off. The volatile products principally consist of crude pyroligneous acid and oil of tar. Pitch is chiefly employed in ship-building. As a medicine, it is stimulant and tonic, and has been used internally in some skin diseases, and in piles. An ointment made of it is also extensively used in cutaneous affections of the scaly.—Dose, 10 gr. to ⁄2 dr.

Pitch, Burgundy. Syn. White pitch, Burgundy pine resin; Pix Burgundica (B. P., Ph. L., E., & D.), L. “Impure resin prepared from the turpentine of Abies excelsa,” or Norway spruce fir. (Ph. L.) “A concrete resinous exudation, probably, in a great measure, from Abies excelsa.” (Ph. E.) It is chiefly used in plasters.

Obs. The importation of this substance has for some years past been gradually lessening in amount, in consequence of the substitution for it of a fictitious pitch, made by melting common resin with linseed oil, and colouring the mass with annotta or palm oil. The physiological action of the two articles is, however, considerably different, since Burgundy pitch acts upon the skin as a powerful local irritant, exciting a slight degree of inflammation, and not unfrequently producing a pimply eruption and an exudation of purulent matter. It is celebrated for its effects when employed as a plaster in all cases where warmth, support, and long adhesion to the skin, are desirable; and in the latter quality no substance equals it. The fictitious Burgundy pitch has similar properties, but in an immensely less degree.

Prepared Burgundy Pitch (Pix Burgundica præparata—Ph. L.) is ordered to be obtained in the same way as that adopted for strained ammoniacum. This plan is, however, seldom, if ever, adopted in trade.

Pitch, Burgundy (Facti′′tious). Syn. Pix Burgundica factitia, L. Prep. By melting good yellow resin, 1 cwt.,with linseed oil, 1 gall., and palm oil (bright), q. s. to colour. The mixture is allowed to cool considerably, and is then pulled with the hands in the same way as lead plaster is treated; after which it is placed in ‘bladders’ or ‘stands’ for sale.

Obs. The product of the above formula is the ‘Burgundy pitch’ of the shops. The ‘pulling’ or ‘working’ destroys the translucency of the resin, and imparts to it the peculiar semi-opacity of foreign Burgundy pitch. Cold water is commonly employed to cool it down. Annotta is often substituted for palm oil as a colouring substance. The addition of some of the ‘droppings’ or ‘bottoms’ of Canada balsam, Chio turpentine, oil of juniper, &c., renders this article nearly equal to foreign pitch; but in commerce this is never attempted, the aim being only the production of a lively colour with moderate toughness. A common melting-pan and fire (if clean, and carefully managed) will succeed sufficiently, but, both for safety and convenience, steam is preferable, and on the large scale, almost indispensable. A good workman can pull and put into stands or casks about 5 cwt. daily; or from 1⁄2 cwt. to 3 cwt. in bladders, the latter quantity depending on the size of the bladders. (See above.)

Pitch, Can′ada. Syn. Hemlock gum, H. pitch. Similar to Burgundy pitch; but from the Abies canadenses, or hemlock spruce fir.

Pitch, Jews’. Asphaltum.

Pitch, Min′eral. Indurated mineral bitumen. See Asphaltum, Bitumen, &c.

PIT′COAL. Syn. Coal; Houille, Fr.; Steinkohle, Ger. This article has been truly described as the most valuable of all those mineral substances from which Great Britain derives its prosperity, and the one which may be regarded as the main support of the whole system of British production. It fuses the metals, it produces the steam which sets our machinery in motion, and, in short, it may be said to render all the resources of this country available for use.

The more important kinds of coal may be classified as follows:—1. Lignite or brown coal (see page 969).—2. Bituminous or caking coals. The most widely diffused and valuable of English coals. They are subdivided into: a. Caking coal. Splinters on heating, but the fragments then fuse together in a semi-pasty mass. The chief sources of this valuable variety of coal are the Newcastle and Wigan districts, b. Cherry coal or soft coal. Lustre very bright; does not fuse, ignites well and burns rapidly. Glasgow, Staffordshire, Derbyshire, Nottingham, Lancashire, &c. c. Splint, rough, or hard coal. Black and glistening; does not ignite readily, but burns up to a clear hot fire. It constitutes the bulk of the great coal fields of North and South Staffordshire, and occurs in the Glasgow district, in Shropshire, Leicestershire, Warwickshire, &c. d. Cannel or parrot coal. Dense and compact, having a shelly fracture, and taking a polish like jet. Splinters in the fire, and burns clearly and brightly. Wigan and other parts of Lancashire, West Glasgow, &c. The curious deposit at Bathgate, near Edinburgh, commonly known as ‘Boghead cannel coal,’ or ‘Torbanehill mineral,’ differs considerably from the ordinary ‘cannels,’—3. Anthracite or stone-coal. The densest, hardest, and most lustrous of all kinds of pitcoal. Burns with little flame or smoke, but gives great heat. South Wales, Devonshire, &c.—4. Steam coal. Approaches nearly to anthracite. Admirably adapted for steam-vessels. South Wales, Tyne district, &c.

The quality of coal may be ascertained by either directly testing its heating power or by chemical analysis. In the investigations undertaken at the Museum of Economic Geology, under the directions of Sir H. De la Beche, and which furnished the materials for the celebrated ‘Admiralty Reports,’ three different methods were adopted for this purpose. These consisted in—the determination of the quantity of water which a given weight of the coal was capable of converting into steam, the quantity of litharge which it was capable of reducing to the metallic state, and, lastly, its ultimate analysis by combustion with oxide of copper. See Organic Substances.

The quantity of sulphur in coal is another matter of importance that may be determined by chemical analysis. (See Sulphur.) The presence of more than 1% of sulphur renders coal unfit for the economical production of good light-gas, and more than 2% of sulphur renders it objectionable for use as domestic fuel. In like manner, coals containing mineral ingredients in excess are to be avoided, not merely on account of the quantity of ashes left by them, but for their tendency to vitrify upon the bars of the furnace, and to produce what is technically called ‘clinkers.’ The presence of much silica or alumina, and more particularly of any of the salts of lime, in ‘steam coal,’ is, on this account, highly objectionable.

For some further information connected with this subject, see Anthracite, Chimneys, Coke, Fuel, Gas, Lignite, Oils, (Mineral), Organic substances, &c.

PLAGUE. (Pestis). “A specific fever attended with bubo of the inguinal and other glands, and occasionally with carbuncles.”

Such is the definition of plague given in the ‘Nomenclature of Diseases’ (published in 1869), drawn up by a joint committee appointed by the College of Physicians.

More detailed accounts of the disease, described by other pathologists, state that it attacks the patient with great suddeness, or only after a few premonitory symptoms. These are:—Shivering, extreme prostration, intense headache and giddiness, excessive restlessness, and an overwhelming sense of anxiety. The patient’s gait becomes uncertain, and he staggers like a drunken man. These symptoms are more or less accompanied by nausea, bilious vomiting, and frequently by bilious diarrhœa. As the disease advances, delirium very frequently sets in; the nausea, vomiting, and diarrhœa increase in intensity, the tongue becomes swollen and covered with a dark fur, whilst the lips, teeth, and nostrils are coated with a dry fetid incrustation. Provided the attack does not terminate fatally, in a very rapid manner, these symptoms are accompanied by sharp pains (increasing in intensity during the progress of the malady) in the groin, armpits, and neck. These pains in the above parts precede the appearance of the buboes, and in many cases, of the carbuncles, which, associated with the fever, are so characteristic of plague. These glandular swellings vary, in different cases, as to the time when they make their appearance. Sometimes they do so during the first day of the attack, at others, after two or three days—and in others, again, not until near the close of the disease. With the buboes and carbuncles, small red purplish spots (petechiæ), frequently appear on the body. The carbuncle is by no means an invariable accompaniment of the disease. Dr Russell, out of 2700 cases, found only 490 in which it showed itself. He states that when carbuncle develops itself, it is distributed over the whole surface of the body with the exception of the scalp, the palms of the hands, and the soles of the feet.

“The plague may be said to assume four degrees of severity:—1. Slight fever, without delirium or buboes. 2. Fever, delirium, and buboes. 3. Fever, delirium, or coma, buboes, carbuncles, and petechiæ/e. 4. Congestive fever, fatal on the first, second, or third day, before the appearance of buboes. The fever, though usually continued, may assume the intermittent or remittent type.”

There is considerable diversity of opinion as to the origin of plague. By some pathologists it is maintained that it spreads solely by contagion; by others the contagion theory is altogether repudiated, and certain local and epidemic agencies are referred to as its source; whilst others, again, adopt a medium view and, whilst not denying its contagious origin, hold that it may also be developed by endemic and epidemic causes. It bears a great resemblance to typhus.

With the exception of the outbreak of plague at Veltianka, in Astrakan, in the beginning of the current year (1879), the pestilence has not visited Western Europe during the present century an exemption which, being so obviously due to the improved sanitary and hygienic conditions of the modern European cities and towns, is a forcible illustration of how largely the power of curtailing the propagation and progress of the scourge is within the means of human control. There can be little, if any, doubt that the same total absence of drainage, and the very possible consequent contamination of drinking water, added to the narrowness of the streets, the overcrowded and badly ventilated state of the houses themselves, and the dirty habits of the inmates, which are also characteristic of those quarters of eastern cities and towns in which plague is always more or less occasionally prevalent, obtained in the fourteenth, fifteenth, sixteenth, and seventeenth centuries, amongst European communities.

We learn, on the authority of Mr Marshall (who gets his figures from the weekly bills of mortality of the period), that during the sixteenth and seventeenth centuries London was seldom free from the pestilence, and that in several years, not usually regarded by historians as plague epochs, it annually slew from less than 1000 to 4000 of the inhabitants.

Between the years 1593 and 1665, five severe outbreaks of the disease occurred in London, and the number of deaths for the respective years were as follows:—1593, 11,503; 1603, 36,269; 1625, 35,417; 1636, 10,400; 1665, 68,596. According to Sir William Petty, the average mortality during these several attacks amounted to about a fifth of the population.

That insanitary surroundings and the spread of plague, whilst sanitary ones and its decline, follow each other like cause and effect, may be emphasised by the statement of two facts:—1. The medical commissioner lately sent by the Russian government to the seat of the late outbreak of the malady in Astrakan, discovered the people dirty in their habits, living in noisome, overcrowded houses, and the atmosphere polluted with the smell of decaying fish, added to which the village was most miserably drained. 2. Ranken records that in Rajpootana plague propagated by the filthy habits of the inhabitants was for some years almost entirely obliterated by the adoption of sanitary precautions.

It may here be noticed that the Astrakan plague was associated with inflammation of the lungs, a feature which led an eminent Russian physician to adopt the opinion, that the Astrakan malady is the same as the Indian plague, which is believed to be the same disease which, under the name of ‘The Black Death,’ committed such appalling devastation in Europe, Asia, and Africa, in the fourteenth century.

In his ‘Epidemics of the Middle Ages,’ Hecker has told of the ravages of this ruthless pestilence, which made its appearance in Europe in 1348. Its devastations at Florence have been very powerfully described by Boccaccio in the introduction to his ‘Decameron.’ Boccaccio was in Naples at the time it was devastating Italy, therefore, it is conjectured, his graphic description must have been derived from hearsay and the reports of eyewitnesses.

In August of the same year it broke out at Dorset, from which county it soon reached Devon and Somerset, and thence rapidly spread throughout England, slaying its thousands in its progress. In London alone it has been estimated that the mortality caused by it amounted to a hundred thousand.

Hecker assumes that in Europe its victims were twenty-five millions. These however, as well as the following figures, must only be received as approximations to the correct numbers, which, owing to the absence of any contemporary bills of mortality, cannot but be very imperfect:—

In Florence there died of the black plague 60,000

In Venice 100,000

In Marseilles, in one month 16,000

In Sienna 70,000

In Paris 50,000

In St Denis 14,000

In Avignon 60,000

In Strasbourg 16,000

In Lübeck 9,000

In Basle 14,000

In Erfurt at least 16,000

In Weimar 5,000

In Lemburg 2,500

In London at least 100,000

In Norwich 51,000

To which may be added:—

Franciscan Friars in Germany 124,434

Minorites in Italy 30,000

From the circumstance—illustrative of the religious and blind bigotry of this period—that the Jews were brutally tortured, massacred, and burnt, on suspicion of having poisoned the wells from which drinking water was drawn, it may be inferred that the wells, owing to the entire absence of drainage, which led to their contamination by sewage matters, contributed largely to the spread of the pestilence.

Of the potency of the contagion disseminated by the ‘Black Death’ Hecker records:—

“Every spot which the sick had touched, their breath, their clothes, spread the contagion; and in all other places the attendants and friends, who were either blind to their danger, or heroically despised it, fell a sacrifice to their sympathy.

“Even the eyes of the patient were considered as sources of contagion, which had the power of acting at a distance, either on account of their unwonted lustre, or the distortion which they always suffer in plague, or in conformity with an ancient notion, according to which the sight was considered as the bearer of a demoniacal excitement.

“The pestilential death of the sick, who expectorated blood, caused a terrible contagion far and near, for even the vicinity of those who had fallen ill of plague was certain death, so that parents abandoned their infected children, and all the ties of kindred were dissolved.”

There is a striking similarity between the above description, referring to the plague of 1348, and the following, which is extracted from Dr Döppner’s official medical report to the Russian government on the plague which manifested itself at Veltianka in Astrakan as lately as January, 1879. Dr Döppner, writes:—

“The necessary remedies were employed to combat the disease. I prescribed especially salicylic acid, muriatic acid, quinine, &c., but everything proved useless. Not a single patient recovered, viz. Dr Koch and six of his assistants died, the priest of the Stanitza, the Cossacks employed in burying the dead; in a word, all those who approached the persons attacked with the disease, although furnished with the means of preservation used in like circumstances, very few escaped the plague.”

No case of plague has occurred in England for more than two centuries, although in 1721 it half depopulated Marseilles, and committed fearful ravages at Moscow, in 1771.

Within the present century it has appeared in Europe at the following places:—At Malta, in 1813; at Calabria, in 1816; at Corfu, in 1818; in Silesia, in 1819; and amongst the Russian troops in Bulgaria, in 1824. In Malta between 4000 and 5000 people fell victims to it.

It made its last appearance in England in 1665, and was especially fatal in London, where it carried off, as we have already seen, 65,596 people. Because of the frightful mortality it occasioned, this particular outbreak of the disease has been named by historians “The Great Plague of London.” Rapidly spreading from Westminster, where it first manifested itself, to the more closely built city, its progress increased with the warm weather, until during the sultry months of August and September it reached its height. “Thus,” writes Pepys in his diary, August 31st, 1665 “this month ends with great sadness upon the public through the greatness of the plague everywhere through the kingdom almost. Every day sadder and sadder news of its increase. In the city died this week 7496, and of them 6102 of the plague. But it is feared the true number of the dead this week is near 10,000; partly from the poor that cannot be taken notice of through the greatness of the number, and partly through the Quakers and others that will not have the bell ring for them.” The general aspect of the pestilence stricken city is thus described by Pepys, “To the Exchange, where I have not been a great while. But, Lord! how sad a sight it is to see the streets empty of people and very few upon the ‘Change. Jealous of every door that one sees shut up, lest it should be plague; and about us two shops in three, if not generally more, shut up.”

The doors of a house infected with the plague were marked with a red cross, and on them was written the words, “The Lord have mercy upon us.” Pepys tells of the fright he experienced when he came upon two houses of this description, in Drury-lane, for the first time; and as he adds that he was compelled to buy some roll tobacco to smell and to chew, it may be concluded that this substance was at that time regarded as somewhat of a safeguard against the disease.

Large carts called nightly at the infected habitations and collecting the bodies of any dead conveyed them to pits, into which they were flung, covered with quicklime. This rude kind of burial became a necessity as the disease gained ground, because the ordinary grave-yards were full to overflowing. “This is the first time,” writes Pepys, “since I have been in the church since I left London for the plague, and it frightened me indeed to go through the church more than I thought it could have done, to see so many graves lie so high upon the churchyards where people have been buried of the plague.”

Such was the fury of the pestilence, and frequently so sudden were its attacks, that wayfarers were often assailed with it in the streets, and staggering like drunken men fell down into the road or pathways insensible or dead. Merchants in their counting-houses, clergymen in the act of reading the burial service, buyers and sellers in the market-place, were similarly assailed by the malignant malady, and it was no uncommon occurrence for the mourner at the grave of a relative or friend one day, to be himself borne to his own tomb the next. It is not improbable the infection may have been conveyed by the rapidly decaying and putrid corpse to large numbers of people, owing to the custom that prevailed of crowds of mourners attending the obsequies.

Pepys records how he saw in broad daylight two or three burials, one at the very heels of another, each followed by forty or fifty people. Furthermore, he states that one day on his way to Greenwich, during the month of August in 1665, he passed a coffin, “with a dead body therein, dead of the plague, lying in an open close belonging to Coombe Farm.”

If this exposure of plague-stricken corpses were at all general, it will readily be perceived how greatly it must have aided the propagation of the pestilence.

Another important agent in the diffusion of the plague must have been the infected clothing, whether of the dead or of those who had been in near or close contiguity to them. On this part of our subject Dr Guy, remarks:—“Nor will this surprise us if we imagine the frantic and successful efforts that must have been made by the non-infected to escape, and the temptation to servants and nurses to appropriate and remove the property of the dying and the dead. Indeed, Dr Hodges accuses the nurses of strangling their patients, and secretly conveying the pestilential taint from sores of the infected to those who were well; and he justifies his accusations ‘of these abandoned miscreants’—the Gamps and Prigs of the seventeenth century—by two instances; the one, of a nurse who, ‘as she was leaving the house of a family, all dead, loaded with her robberies, fell down dead under her burden in the streets,’ the other, of a worthy citizen who, being considered dying by his nurse, was beforehand stripped by her, but recovering again, he came a second time into the world naked.”

Lastly, in endeavouring to account for the great prevalence and excessively fatal character of this pestilence, we must not leave out of consideration one important factor—viz. fear.

We can easily conceive how powerfully the appalling incidents by which the plague was accompanied must have affected the imaginations of those who were in its midst, and thus have stimulated the fear, which, acting by its depressing mental effect, would predispose and prepare men and women for the reception of the contagion.

In ‘Pepys’ Diary’ we find a circumstance recorded corroborative of this. A certain alderman, stumbling at night over a dead body in the street, when he reaches home tells his wife of his adventure, and she is forthwith seized with the plague and dies of it. Furthermore, the belief derived from knowledge of the deadly character of the disease, operating upon the minds of those who were attacked by it, would greatly diminish the chances of their recovery, since they would most likely regard seizure and death as synonymous.

There is an old Eastern fable which tells of a traveller journeying from an infected city, and overtaking the plague, who had not long left it. The traveller accosts the plague and reproaches him for having slain thirty thousand people in the city. “You are in error there,” replied the plague, “I slew only ten thousand, fear slew the rest.”

Tropical climates are never visited by plague. In those countries which suffer from its ravages it prevails most during the hot months of the year, and its virulence and spread appear to be commensurate with increase of temperature. In northern climates it diminishes with the approach of cold weather. In Europe it has always been most fatal during the summer and autumn, and in the great plague of London the greatest mortality prevailed during the months of August and September.

PLAICE. The Platessa vulgaris, a well-known flat fish, common to both the English and Dutch coasts. Its flesh is good, and easy of digestion, but more watery than that of the flounder.

PLANTAIN. The plantain, which belongs to the nat. ord. Musaceæ, and is a native of the East Indies, is cultivated in all tropical and subtropical regions of the world, in many of which it constitutes the principal food of the inhabitants. There are a great many varieties of the plantain, in some of which the stem is 15 or 20 feet high, whilst in others it does not exceed 6 feet. It is one of the largest of the herbaceous plants.

The fruit is sometimes eaten raw, but is more generally boiled or roasted. It contains both starch and sugar. Boiled and beaten in a mortar, it forms the common food of the negroes in the West Indies. It also constitutes the chief food of the Indians of North and South America.

Humboldt has calculated that the food produce of the plantain is 44 times greater than that of the potato and 133 times that of wheat.

The banana is a species of plantain. See Banana.

PLASMA. The liquor sanguinis. A tenacious plastic liquid, forming the coagulating portion of the blood, and that in which the corpuscles float.

PLAS′TER. (In boiling, &c.) See Mortar.

Plaster of Paris. Calcined sulphate of lime. See Alabaster, Gypsum, Lime, &c.

PLASTER. (In pharmacy.) Syn. Emplastrum, L. Plasters (emplastra) are external applications that possess sufficient consistence not to adhere to the fingers when cold, but which become soft and adhesive at the temperature of the human body.

Plasters are chiefly composed of unctuous substances united to metallic oxides, or to powders, wax, or resin. They are usually formed, whilst warm, into ⁄2-lb. rolls, about 8 or 9 inches long, and wrapped in paper. When required for use, a little is melted off the roll by means of a heated iron spatula, and spread upon leather, linen, or silk. The less adhesive plasters, when spread, are usually surrounded with a margin of resin plaster, to cause them to adhere.

In the preparation of plasters the heat of a water bath, or of steam, should alone be employed. On the large scale, well-cleaned and polished copper or tinned copper pans, surrounded with iron jackets, supplied with high-pressure steam, are used for this purpose. The resins and gum resins that enter into their composition are previously purified by straining. After the ingredients are mixed, and the mass has acquired sufficient consistence by cooling, portions of it are taken into the hands, anointed with a little olive oil, and well pulled or worked until it becomes solid enough to admit of being formed into rolls. To promote the cooling of the plaster it is usual to plunge it into cold water, and to expose it to the action of the fluid by working it about under the surface, after which it is well pulled in the hands to remove the superfluous water; but this process must not, on any account, be practised on compound plasters, containing odorous substances, or substances soluble in water. These should be suffered to cool on an oiled marbled slab, until sufficiently ‘stiff’ to be formed into rolls. Many plasters, as those of lead and resin, derive much of their whiteness and beauty from the treatment just referred to. White plasters are not, however, always the best; but they are those which are most admired, and the most sought after in trade.

Plasters are preserved by enveloping the rolls with paper, to exclude the air as much as possible, and by keeping them in a cool situation. A few, as those of belladonna and ammoniacum with mercury, are commonly placed in pots. When kept for any length of time, they are all more or less apt to become hard and brittle, and to lose their colour. When this is the case, they should be remelted by a gentle heat, and sufficient oil added to the mass to restore it to a proper consistence.

The operation of spreading plasters for use requires skill and experience on the part of the operator. Various textures are employed for the purpose, of which linen or cotton cloth, or leather, are those most generally employed. Silk and satin are used for ‘court plaster.’ The shape and size must be regulated by the part to which they are to be applied.

On the large scale plasters are spread by means of a ‘spreading machine.’

Compound plasters are now much less frequently employed in medicine than formerly. Those principally in use are such as afford protection to sores and abraded surfaces, and give support to the parts. A few, however, which contain acrid, stimulating, and narcotic substances, and operate as rubefacients, blisters, or anodynes, are still retained in the Pharmacopœias.

Plaster of Ac′onite. Syn. Emplastrum aconiti, L. Prep. (Curtis.) Gently evaporate tincture of aconite to the consistence of a soft extract, then spread a very small portion over the surface of a common adhesive plaster, on either calico or leather. Mr Curtis has strongly recommended this plaster in neuralgia. A little of the alcoholic extract may be employed instead of that obtained fresh from the tincture.

Plaster, Adhe′′rent. See Plaster, Soap (Compound).

Plaster, Adhe′sive. See Plaster, Resin, Court p., &c.

Plaster, Adhesive Lime. Syn. Emplastrum adhæsivum calcareum. Prep. Soap of lime, 200 parts; boiled turpentine, 100 parts; suet, 25 parts.

Plaster, Ammoni′acal. Syn. Dr Kirkland’s volatile plaster; Emplastrum ammoniæ, E. a. hydrochloratis, L. Prep. Take of lead plaster, 1 oz.; white soap (shaved fine), ⁄2 oz.; melt them together, and, when nearly cold, add of sal ammoniac (in fine powder), 1 dr. Stimulant and rubefacient. Dr Paris, who highly recommends it in pulmonary affections, employs double the above proportion of sal ammoniac. Its efficacy depends on the gradual extrication of free ammonia by the decomposition of the sal ammoniac, on which account it is proper to renew the application of it every 24 hours.

Plaster of Ammoni′acum. Syn. Emplastrum ammoniaci (Ph. L., E., & D.), L. Prep. 1. (Ph. L. & E.) Ammoniacum (strained), 5 oz.; dilute acetic acid (distilled vinegar), 8 fl. oz. (9 fl. oz.—Ph. E.); dissolve, and, frequently stirring, evaporate by a gentle heat to a proper consistence.

2. (Ph. D.) Gum ammoniacum (in coarse powder), 4 oz.; proof spirit, 4 fl. oz.; dissolve by the aid of a gentle heat, and evaporate, as before.

Obs. This plaster is adhesive, stimulant, and resolvent, and is employed in scrofulous and indolent tumours, white swellings, &c. In the Ph. D. 1826 vinegar of squills was ordered instead of distilled vinegar.

Plaster of Ammoniacum with Hem′lock. Syn. Emplastrum ammoniaci cum cicutâ, L. Prep. (Ph. E. 1744.) Gum ammoniacum, 8 oz.; vinegar of squills, q. s. to dissolve; hemlock juice, 4 oz.; gently evaporate, as before. In cancerous and other painful tumours. A better plan is to add 1 dr. of extract of hemlock to 1⁄4 oz. of strained ammoniacum (previously reduced to a proper consistence with a little distilled vinegar), melted by a very gentle heat.

Plaster of Ammoniacum with Mer′cury. Syn. Emplastrum ammoniaci cum hydrargyro (B. P., Ph. L., E., & D.), L. Prep. 1. (Ph. L. & E.) Olive oil, 1 dr.; heat it in a mortar, add of sulphur, 8 gr.; triturate; further add of mercury, 3 oz.; again triturate, and when the globules are extinguished, add it to ammoniacum (strained), 1 lb. (12 oz., B. P.), previously melted by a gentle heat, and mix them well together.

2. (Ph. D.) From ammoniacum plaster, 4 oz.; mercurial plaster, 8 oz.; melted together by a gentle heat, and then stirred constantly until nearly cold.

3. (Wholesale.) Take of mercury, 38 oz.; prepared sevum, 5 oz.; triturate, as last, and add the mixture to strained ammoniacum, 10 lbs., previously sufficiently softened by a gentle heat. Possesses a fine blue colour, and is quickly made.

Obs. This plaster cannot be rolled till considerably cooled, and neither this nor the simple plaster must be put into water. It is powerfully discutient, and is applied to indurated glands, indolent tumours, &c.

Plaster, An′odyne. See Plaster, Opium, Plaster, Belladonna, &c.

Plaster, Antimo′′nial. Syn. Emplastrum antimoniale, E. antimonii potassio-tartratis, L. Prep. (U. C. Hosp.) By sprinkling tartar emetic, in very fine powder, on the surface of a spread Burgundy pitch (or common adhesive) plaster. It has been successfully applied to the nape of the neck, in the scarlatina of children; also the chest, in phthisis; and, with the addition of a little opium, in rheumatic affections of the joints.

Plaster, Arnica. (Ph. U. S.) Syn. Emplastrum arnicæ. Prep. Alcoholic extract of arnica, 1⁄2 oz.; resin plaster, 3 oz. Add the extract to the plaster previously melted over a water bath, and mix it thoroughly.

Plaster, Aromatic. Syn. Stomach plaster; Emplastrum aromaticum, L. Prep. (Ph. D. 1826.) Strained frankincense (thus), 3 oz.; beeswax, ⁄2 oz.; melt them together, and, when the mass has considerably heated, add, of powdered cinnamon, 6 dr.; oils of allspice and lemons, of each 2 dr. Stimulant; applied over the stomach in dyspepsia, spasms, nausea, flatulence, &c. Camphor, 1 dr., is commonly added.

Plaster of Assafœtida. Syn. Antihysteric plaster, Antispasmodic p.; Emplastrum assafœtidæ (Ph. E.), E. antihystericum, &c., L. Prep. (Ph. E.) From lead plaster and strained assafœtida, of each 2 oz.; strained galbanum and beeswax, of each 1 oz.; melted together. Antispasmodic; applied to the stomach or abdomen in spasms, hysteria, &c.; and to the chest in hooping-cough.

Plaster, Baynton’s Adhesive. Prep. From yellow resin, 1 oz.; lead plaster, 1 lb.; melted together. Recommended for bad legs, and other like sores.

Plaster of Belladon′na. Syn. Emplastrum belladonnæ (B. P., Ph. L., E., & D), L. Prep. 1. (Ph. L.) Soap plaster, 3 oz.; melt it by the heat of a water bath; add of extract of belladonna (deadly nightshade), 3 oz.; and keep constantly stirring the mixture until it acquires a proper consistence.

2. (Ph. E.) Resin plaster, 3 oz.; extract of belladonna, 1⁄2 oz.; as the last.

3. (Ph. D.) Resin plaster, 2 oz.; extract of belladonna, 1 oz.

4. (B. P.) Extract of belladonna, 3; resin plaster, 3; rectified spirit, 6; rub the extract and spirit together in a mortar, and when the insoluble matter has subsided, decant the clear solution, remove the spirit by distillation or evaporation, and mix the alcoholic extract thus obtained with the resin plaster melted at the heat of a water bath, continuing the heat until with constant stirring the plaster has acquired a suitable consistence.

Uses, &c. As a powerful anodyne and antispasmodic; in neuralgia and rheumatic pains, and as an application to painful tumours. The plaster of the shops is usually deficient in extract. The following formula is in common use in the wholesale trade:—Lead plaster and resin plaster, of each 2⁄2 lbs.; extract of belladonna, 1⁄4 lb. This plaster must not be ‘pulled’ in water.

Plaster, Berg’s Antirheumatic. Syn. Gout paper; Emplastrum antirheumaticum, Charta antirheumatica, L. Prep. By digesting euphorbium, 2 parts, and cantharides, 1 part (both in powder), in rectified spirit, 10 parts, for eight days; adding to the strained liquid, black resin and Venetian turpentine, of each 4 parts; assisting the mixture by a gentle heat. Two or three coats of the product are successively spread over the surface of thin paper. Used in gout and rheumatism. (‘Anat. of Quackery.’)

Plaster, Black. Syn. Emplastrum nigrum. Prep. Mr Sharp’s black plaster was formed by boiling together olive oil, 13 oz.; wax, 2⁄2 oz.; carbonate of lead, 10 oz.

Plaster, Black Diach′ylon. See Court plaster.

Plaster of Black Pitch. Syn. Emplastrum picis nigræ, L. Prep. (Ph. Wirtem.) Black pitch, black resin, and beeswax, of each 8 parts; suet, 1 part; melted together. Rubefacient and stimulant.

Plaster, Blistering. See Plaster of Cantharides.

Plaster, Bree’s Antiasthmatic. Prep. From lead plaster, 1 oz.; olive oil, 1 dr.; melted together, and, when somewhat cooled, mixed with powdered camphor, 2 dr.; powdered opium, 1 dr., and at once spread on leather.

Plaster, Brown. Syn. Emplastrum fuscum, L.; Onguent de la mère, Fr. The butter, lard, oil, suet, and wax should be first melted together, and the heat gradually increased until they begin to smoke; the litharge is then to be sifted in, and the stirring and heat continued until the mixture assumes a brown colour; the pitch is next added, and the whole stirred for some time longer.

Plaster, Brown Diach′ylon. See Plaster of Galbanum.

Plaster, Bryony. (Boerhaave.) Syn. Emplastrum bryoniæ. Prep. Strained galbanum, 4 oz.; wax plaster, 9 oz.; olive oil, 1 oz. Melt together and add powdered bryony root, 2 oz.; flowers of sulphur, 1 oz.; Ethiops mineral, 2 dr.; stir till cold.

Plaster of Bur′gundy Pitch. Syn. Cephalic plaster, Breath p.; Emplastrum picis (B. P., Ph. L. & E.), E. p. compositum, E. p. Burgundicæ, L. Prep. 1. (Ph. L.) Prepared (strained) Burgundy pitch, 2 lbs.; prepared frankincense (thus), 1 lb.; yellow resin and beeswax, of each 4 oz.; melt them together, then add, olive oil and water, of each 2 fl. oz.; expressed oil of nutmeg (mace), 1 oz.; and, constantly stirring, evaporate to a proper consistence.

2. (Ph. E.) Burgundy pitch, 1 lb.; resin and beeswax, of each 2 oz.; olive oil and water, of each 1 fl. oz.; oil of mace, ⁄2 oz.; as the last.

3. (B. P.) Burgundy pitch, 26; common frankincense, 13; resin, 4⁄2; yellow wax, 4⁄2; expressed oil of nutmegs, 1; olive oil, 2; water, 2; add the oil and the water to the other ingredients, previously melted together; stir, and evaporate to a proper consistency.

Uses, &c. Burgundy-pitch plaster is stimulant, rubefacient, and counter-irritant. It is a common application to the chest in pulmonary affections, to the joints in rheumatism, and to the loins in lumbago. Spread on leather, it forms a good warm plaster to wear on the chest during the winter. “When it produces a serous exudation, it should be frequently renewed.”

The Burgundy-pitch plaster of the shops is commonly made as follows:—Factitious Burgundy pitch (bright coloured), 42 lbs.; palm oil (bright), ⁄4 lb.; beeswax (bright), 5 lbs.; melt, and, when nearly cold, add, of oil of mace, 6 oz.; oil of nutmeg, 1 oz.

Plaster of Burgundy Pitch (Irritating). (Ph. G.) Syn. Emplastrum picis irritans. Prep. Burgundy pitch, 32 oz.; yellow wax, 12 oz.; turpentine, 12 oz.; euphorbium, 3 oz.

Plaster, Califa′cient. Syn. Warm plaster; Emplastrum calefaciens (Ph. D.), L. Prep. (Ph. D.) 1. Plaster of cantharides, ⁄2 lb. (1 part); Burgundy pitch, 5⁄2 lbs. (11 parts); melt them together by a gentle heat, and stir the mixture as it cools until it stiffens. Stimulant, rubefacient, and counter-irritant; in a variety of affections. In some persons, when long applied, it blisters or produces a running sore.

2. (Ph. B.) Cantharides in coarse powder, 4 oz.; boiling water, 1 pint; expressed oil of nutmeg, 4 oz.; yellow wax, 4 oz.; resin, 4 oz.; soap plaster, 3⁄4 lbs.; resin plaster, 2 lbs. Infuse the cantharides in the boiling water for six hours; squeeze strongly through calico, and evaporate the expressed liquid by a water bath till reduced to one third. Then add the other ingredients and melt in a water bath, stirring well till the whole is thoroughly mixed.

Plaster, Camphor. Syn. Emplastrum camphoræ. Camphor is best applied by sprinkling the powder on the warm surface of a spread adhesive or other plaster. Blisters are treated in this way to prevent strangury.

Plaster, Can′cer. Syn. Emplastrum anticancrosum, L. Prep. 1. Wax plaster, 1 oz.; extract of hemlock, 1 dr.; levigated arsenious acid, ⁄2 dr.

2. (Richter.) Extract of hemlock, 1 oz.; extract of henbane, ⁄2 oz.; powdered belladonna, 1 dr.; acetate of ammonia, q. s. to form a plaster. Both the above must be used with great caution. See Cancer, &c.

Plaster of Canthar′ides. Syn. Blistering plaster, Vesicant p., Plaster of Spanish flies; Emplastrum cantharidis (B. P., Ph. L., E., & D.), E. c. vesicatoræ, E. lyttæ, L. Prep. 1. (Ph. L.) Yellow wax and suet, of each 7⁄2 oz.; lard, 6 oz.; resin, 3 oz.; melt them together, remove the vessel from the fire, and, a little before they concrete, sprinkle in of cantharides (in very fine powder), 1 lb. (12 oz. B. P.), and mix.

2. (Ph. E.) Cantharides, beeswax, resin, and suet, equal parts; as the last.

3. (Ph. D.) Spanish flies, 6 oz.; prepared lard, resin, and yellow wax, of each 4 oz.; proceed as before, and “stir the mixture constantly until the plaster is cool.”

4. (Wholesale.) From beeswax and good lard, of each 4 lbs.; flies and yellow resin, of each 6 lbs.; suet, 10 lbs. A commonly used formula, the product of which is, however, greatly inferior to that of the Pharmacopœia.

Obs. All the above are used to raise blisters. The plaster is spread on white leather with a cold knife, and is surrounded with a margin of resin plaster to make it adhere. A piece of thin muslin or tissue paper is usually placed between the plaster and the skin to prevent absorption. A little powdered camphor is sometimes sprinkled on the surface of the spread plaster, to prevent strangury. A better mode of obviating the action on the urinary organs is by the copious use of diluents. This plaster should be rolled in starch powder, and not with oil.

Plaster of Cantharides (Compound). Syn. Emplastrum cantharidis compositum, L. Prep. (Ph. E.) Venice turpentine, 4⁄2 oz.; cantharides and Burgundy pitch, of each 3 oz.; beeswax, 1 oz.; verdigris (in fine powder), ⁄2 oz.; powdered mustard and black pepper, of each 2 dr.; mix at a heat under 212° Fahr. Stronger than the last, and quicker in its action; but it causes more pain, and is much more apt to occasion troublesome ulcerations. Used in gout, spasms of the stomach, &c.

Plaster, Capuchin′. See Plaster of Euphorbium.

Plaster of Car′bonate of Lead. Syn. Emplastrum plumbi carbonatis, E. cerussæ, L. Prep. (P. Cod.) Carbonate of lead, 1 lb.; olive oil and water, of each 2 lbs.; boil them together until they combine and form a plaster; lastly, remelt this with white wax, 3⁄2 oz. Its properties resemble those of ordinary lead plaster. An excellent emollient and defensive plaster. See Plaster, Mahy’s.

Plaster, Cephal′ic. Syn. Labdanum plaster; Emplastrum cephalicum, E. labdani, L. Prep. (Ph. L. 1788.) Labdanum, 3 oz.; frankincense (thus), 1 oz.; melt, and add to the mixture, when nearly cold, powdered cinnamon and expressed oil of mace, of each ⁄2 oz.; oil of mint, 1 dr. Applied to the forehead or temples, in headache; to the stomach, in colds, &c. See Plaster of Burgundy pitch, &c.

Plaster, Cheselden’s Stick′ing. Syn. Emplastrum plumbi cum pice, L. Prep. From lead plaster, 2 lbs.; Burgundy pitch (genuine), 1 oz.; melted together.

Plaster, Corn. Syn. Emplastrum ad clavos, L. Prep. 1. Resin plaster, 5 parts; melt, stir in of sal ammoniac (in fine powder), 1 part, and at once spread it on linen or soft leather.

2. (Kennedy’s.) From beeswax, 1 lb.; Venice turpentine, 5 oz.; verdigris (in fine powder), 1⁄2 oz.; mixed by a gentle heat, and spread on cloth. It is cut into pieces, and polished, and of these 1 dozen are put into each box.

3. (Le Foret.) Galbanum plaster, 2 oz.; melt by a very gentle heat; add, sal ammoniac and saffron, of each ⁄2 oz.; powdered camphor, 2 oz.; and, when nearly cold stir in of liquor of ammonia, 2 oz. Applied, spread on leather, to the corn only, as it will blister the thinner skin surrounding its base.

4. (Ph. Sax.) Galbanum plaster, 1 oz.; pitch, ⁄2 oz.; lead plaster, 2 dr.; melt them together, and add verdigris and sal ammoniac (in fine powder), of each 1 dr. For other formulæ, see Plaster of Verdigris (below), and Corns.

Plaster, Court. Syn. Sticking plaster, Isinglass p.; Emplastrum ichthyocollæ, E. adhesivum anglicum, L. Prep. 1. Isinglass, 1 part; water, 10 parts; dissolve, strain the solution, and gradually add to it of tincture of benzoin, 2 parts; apply this mixture, gently warmed, by means of a camel-hair brush, to the surface of silk or sarcenet, stretched on a frame, and allow each coating to dry before applying the next one, the application being repeated as often as necessary; lastly, give the prepared surface a coating of tincture of benzoin or tincture of balsam of Peru. Some manufacturers apply this to the unprepared side of the plaster, and others add to the tincture a few drops of essence of ambergris or essence of musk.

2. (Deschamps.) A piece of fine muslin, linen, or silk is fastened to a flat board, and a thin coating of smooth, strained flour paste is given to it; over this, when dry, two coats of colourless gelatin, made into size with water, q. s., are applied warm. Said to be superior to the ordinary court plaster.

3. (Liston’s.) Soak isinglass, 1 oz., in water, 2⁄2 fl. oz., until it becomes swollen and quite soft; then add of proof spirit, 3⁄2 fl. oz., and expose the mixture to the heat of hot water, frequently stirring, until the union is complete; lastly, apply four coats of the solution to the surface of oiled silk nailed to a board, by means of a soft brush.

4. (Dr Paris.) Black silk or sarcenet is strained and brushed over 10 or 12 times with the following composition:—Gum benzoin, ⁄2 oz.; rectified spirit, 6 oz.; dissolve. In a separate vessel dissolve of isinglass, 1 oz., in as little water as possible; strain each solution, mix them, decant the clear portion, and apply it warm. When the last coating is quite dry, a finishing coat is given with a solution of Chio turpentine, 4 oz., in tincture of benzoin, 6 oz.

Obs. The common ‘COURT PLASTER’ of the shops is generally prepared without using spirit, and with merely sufficient tincture of benzoin, or other aromatic, to give it an agreeable odour. Formerly, black silk or sarcenet was exclusively employed as the basis of the plaster, but at the present time checkered silk is also much in favour. ‘Flesh-coloured court plaster’ is likewise fashionable. ‘Transparent court plaster’ is prepared on oiled silk. ‘Waterproof court plaster’ is simply the common plaster which has received a thin coating of pale drying oil on its exposed surface. The FINEST COURT PLASTER of the West-end houses is now prepared on gold-beaters’ skin (or the prepared membrane of the cæcum of the ox), one side of which is coated with the isinglass solution, as above, and the other with pale drying oil or a solution of either gutta percha or caoutchouc in chloroform, or in bisulphuret of carbon.

Plaster of Cro′ton Oil. Syn. Emplastrum crotonis, E. olei tiglii, L. Prep. (Bouchardat.) To lead plaster, 4 parts, melted by a very gentle heat, add of croton oil, 1 part. A powerful counter-irritant; it also generally acts powerfully on the bowels.

Plaster of Cum′in. Syn. Emplastrum cumini (Ph. L.), E. cymini, L. Prep. 1. (Ph. L.) Burgundy pitch, 3 lbs.; beeswax, 3 oz.; melt, add of cumin seed, caraways, and bay-berries, of each (in powder) 3 oz.; next add of olive oil and water of each 1⁄2 fl. oz., and evaporate to a proper consistence.

2. (Wholesale.) From yellow resin, 7 lbs.; beeswax and linseed oil, of each ⁄2 lb.; powdered cumin and caraway seeds, of each 7 oz.; mix.

Obs. This is a mere revival of the formula of the Ph. L. 1724. In that of the Ph. L. 1778 no water was ordered, and the powders simply stirred into the melted mass shortly before it cools; the common practice in all laboratories.

Cumin plaster is carminative, stimulant, and discutient. It is applied over the regions of the stomach and bowels in colic, dyspepsia, and flatulence, and is also applied to indolent tumours. It has long been a favourite remedy with the lower classes.

Plaster, Delacroix’s Agglu′tinative. Syn. Emplastrum glutinans Sancti Andreæ a Cruce, E. picis cum elemi, L. Emplâtre d’André de la Croix, Fr. Prep. (P. Cod.) From Burgundy pitch, 25 parts; gum elemi, 6 parts; Venice turpentine and oil of bays, of each 3 parts; melted together, and strained.

Plaster, Diach′ylon. See Plaster of Lead.

Plaster, Diapal′ma. See Plaster, Palm.

Plaster of El′emi. Syn. Emplastrum elemi, L. Prep. From wax plaster, 3 parts; gum elemi, 1 part; melted together by a gentle heat. Stimulant and discutient. Used for issues, &c.

Plaster of Euphor′bium. Syn. Emplastrum euphorbii, L. Prep. 1. (Guy’s Hosp.) Burgundy pitch plaster, 8 oz.; melt, and add of euphorbium (in powder), 1 dr.

2. (Capuchin plaster—Ph. Wirt.) Burgundy pitch and beeswax, of each 3 oz.; Venice turpentine, 1 oz.; melt them together, add, gum ammoniacum, olibanum, mastic, and lapis calaminaris, of each 1 oz.; euphorbium, pyrethrum, and common salt, of each (in powder) 2 oz.; and stir until the mass concretes. Both of the above are stimulant, rubefacient, and counter-irritant.

Plaster, Fayard’s. See Paper (Gout).

Plaster of Flower of Ointments. Syn. Emplastrum flos unguentorum dictum, L. Prep. From frankincense (thus), yellow resin, suet, and beeswax, of each 1 lb.; olibanum, ⁄2 lb.; Venice turpentine, 5 oz.; gum myrrh, 2 oz.; white wine, 16 fl. oz.; boil to a plaster, adding, before the mass cool, of camphor, ⁄2 oz. Calorifacient and stimulant.

Plaster of Frank′incense. Syn. Strengthening plaster; Emplastrum thuris, E. roborans, L. Prep. (Ph. L. 1788.) To lead plaster, 2 lbs., melted by a gentle heat, add of frankincense (thus), ⁄2 lb., dragon’s blood (in powder), 3 oz., and stir well. In muscular relaxations, weak joints, &c. Mr Redwood says that a “better-looking plaster is produced by melting the frankincense and dragon’s blood together, and straining them through a cloth, then mixing these with the lead plaster previously melted.” See Plaster of Oxide of Iron.

Plaster of Gal′banum. Syn. Compound galbanum plaster, Yellow diachylon, Gum plaster, Diachylon with the gums, Emplastrum galbani (B. P., Ph. L.), E. gummosum (Ph. E.), L. Prep. 1. (Ph. L.) Take of strained galbanum, 8 oz.; common turpentine, 1 oz.; melt them together, then add of prepared frankincense (thus), 3 oz.; and next, of lead plaster, 3 lbs., previously melted over a slow fire.

2. (Ph. E.) Gum ammoniacum and galbanum, of each ⁄2 oz.; melt them together, strain, and add, of litharge plaster, 4 oz.; beeswax, ⁄2 oz. (both previously melted); and mix the whole thoroughly. These proportions are the same as those of the B. P.

3. (Wholesale.) From lead plaster, 42 lbs.; yellow resin, 12 lbs.; strained galbanum, 3 lbs.; strained assafœtida, 1 oz.

Obs. Galbanum plaster is stimulant and resolvent, and is much used in indolent, scrofulous, and other tumours, painful gouty and rheumatic joints, in rickets, &c.

Plaster, Gaulthier’s. Prep. (Guibourt.) Palm plaster, 12 parts; olive oil and white wax, of each 1 part; melt, and add of Venice turpentine, 2 parts. More adhesive than the simple PALM PLASTER.

Plaster of Gin′ger. Syn. Emplastrum zingiberis, L. See Ginger.

Plaster, Gout. Syn. Emplastrum Antarthriticum, L. See Plaster of Galbanum, Pitch, &c.; Paper, Gout.

Plaster of Gum. See Plaster of Galbanum.

Plaster of Hem′lock. Syn. Emplastrum conii, E. cicutæ, L. Prep. 1. Wax, 1 part; Burgundy pitch, 9 parts; melt them together, and add of extract of hemlock, 3 parts.

2. (Ph. Bat.) Lead plaster and beeswax, of each 1 lb.; olive oil, 6 fl. oz.; melt, and add of powdered hemlock (recent), 1 lb.

Obs. Hemlock plaster is occasionally used as an application to painful and malignant ulcers and tumours, painful joints, &c. A spread plaster of it, with 6 or 8 gr. of tartar emetic (in very fine powder) sprinkled over its surface, has been highly extolled as a counter-irritant in hooping-cough, phthisis, &c.

Plaster of Hen′bane. Syn. Emplastrum Hyoscyami, L. Prep. As the last, but using henbane instead of hemlock. As an anodyne, in various external affections.

Plaster of I′odide of Lead. (Ph. B.) Syn. Emplastrum plumbi iodidi. Prep. Add iodide of lead in fine powder, 1 oz.; to soap plaster and resin plaster, of each 4 oz., previously melted together. Mix thoroughly.

Plaster of Iodide of Potas′sium. Syn. Emplastrum potassii iodidi (Ph. L.), L. Prep. (Ph. L.) Iodide of potassium, 1 oz.; olive oil, 2 fl. dr.; triturate them together, then add, of strained frankincense (thus), 6 oz.; wax, 6 dr.; and stir constantly until the mass cools. “This plaster is to be spread on linen, rather than on leather.” Used as a discutient or resolvent; more particularly as an application to scrofulous tumours and indurations.

Plaster of I′odine. Syn. Emplastrum iodinii, L. Prep. Triturate iodine, 1 dr., in a warm mortar, with olive oil, 1 oz.; then add, of beeswax, 1 oz.; yellow resin, ⁄2 oz.; previously melted together, and stir the whole until it concretes. It should be, preferably, spread at once on leather, and applied shortly after being prepared. Used as the last.

Plaster of Iodine (Compound). Syn. Emplastrum iodinii compositum, L. Prep. 1. Iodine, 1 dr.; iodide of potassium, 2 dr.; rub them to a fine powder, add this to lead powder, 2 oz.; Burgundy pitch, 1 oz.; previously melted together, and just about to concrete. More active than either of the preceding.

2. (Emp. iod. cum belladonnâ.) To belladonna plaster, 2 oz., melted by a very gentle heat, add iodine and iodide of potassium (in fine powder), of each 1 dr.; and stir the mixture until nearly cold. Powerfully resolvent and anodyne. Used in the same cases as the preceding, when there is much pain.

Plaster of I′ron. See Plaster of oxide of Iron.

Plaster of I′′singlass. See Plaster, Court.

Plaster, Is′sue. Syn. Emplastrum ad fonticulos, Sparadrapum pro fonticulis, L. Prep. 1. From beeswax, ⁄2 lb.; Burgundy pitch and Chio turpentine, of each 4 oz.; vermilion and orris powder, of each 1 oz.; musk, 4 gr.; melted together and spread upon linen. This is afterwards polished with a smooth piece of glass moistened with water, and cut into pieces.

2. (Ph. Aust.) Yellow wax, 6 oz.; mutton suet, 2 oz.; lard, 1⁄2 oz.; melt, add of turpentine, 1⁄2 oz., and afterwards of red lead, 4 oz.; dip pieces of linen into the melted mixture, pass these between rollers, and, when cold, polish them, as before, and cut them into squares. The issue plaster (issue paper; charta ad fonticulos) of the Ph. Suecica is a nearly similar compound, with the addition of about 1-48th part of verdigris, in very fine powder, and being spread upon paper.

Plaster, Kennedy’s. See Plasters, Corn.

Plaster, Kirkland’s. See Plaster, Ammoniacal.

Plaster of Lab′danum. See Plaster, Cephalic.

Plaster of Lead. Syn. Lead plaster, Litharge p., Common p., Diachylon, Simple diachylon, White d.; Emplastrum plumbi (B. P., Ph. L.), E. lythargyri (Ph. E. & D.), E. commune, Diachylon simplex, L. Prep. 1. (Ph. L.) Oxide of lead (litharge), in very fine powder, 6 lbs.; olive oil, 1 gall.; water, 1 quart; boil them over a slow fire, constantly stirring to the consistence of a plaster, adding a little boiling water, if nearly the whole of that used in the beginning should be consumed before the end of the process.

2. (Ph. E.) Litharge, 5 oz.; olive oil, 12 fl. oz.; water, 8 fl. oz.; as the last.

3. (Ph. D.) Litharge, 5 lbs.; olive oil, 1 gall.; water, 1 quart.

4. (Otto Kohnke.) For each lb. of litharge employed, add ⁄4 pint of colourless vinegar (each fl. oz. of which is capable of saturating ⁄2 dr. of carbonate of potassa); add the oil, boil until all moisture is evaporated, and until only a few striæ of litharge rise to the surface, then remove the vessel from the heat, add gradually ⁄3 to ⁄2 as much vinegar as before, and boil the mixture to a proper consistence.

5. (Wholesale.) From Genoa oil, 7 galls. (or 65 lbs.); litharge (perfectly free from copper), 28 lbs.; water, 2⁄2 galls.; boil to a plaster, as before.

6. (B. P.) Oxide of lead, in very fine powder, 1; olive oil, 2⁄2; water, 1; boil all the ingredients together gently by the heat of a steam bath, and keep them simmering for 4 or 5 hours, stirring constantly until the product acquires the proper consistence for plaster, adding more water during the process, if necessary.

Obs. The London College orders too little oil. The second, fourth, and fifth formulæ produce beautiful plasters, that keep well; those of the others, although very white, get hard and brittle much more rapidly. The proper proportion of oil is fully 2⁄3 times the weight of the litharge,—2⁄2 times appears the best quantity; and without this is used, the plaster speedily gets hard and non-adhesive. The process consists in putting the water and the litharge into a perfectly clean and well-polished tinned copper or copper-pan, mixing them well together with a spatula, adding the oil, and boiling, with constant stirring, until the plaster is sufficiently hard, when thoroughly cold. This process usually occupies from 4 to 5 hours, but by adopting the fourth formula an excellent plaster may be made in from 20 to 30 minutes. This plaster is generally cooled by immersion in cold water; and to render it very white, a quality highly prized in the trade, it is usual to submit it to laborious ‘pulling,’ in the manner already noticed.

Use. As a simple defensive plaster or strapping; but principally as a basis for other plasters.

Plaster, Liston’s. See Plaster, Court.

Plaster, Mahy’s. Syn. Emplastrum plumbi carbonatis, E. p. c. compositum, L. Prep. (Ph. U. S.) Carbonate of lead (pure white lead), 1 lb.; olive oil, 32 fl. oz.; water, q. s.; boil them together, constantly stirring until perfectly incorporated; then add, of yellow wax, 4 oz.; lead plaster, 1⁄2 lb.; and when these are melted, and the mass somewhat cooled, stir in of powdered orris root, 9 oz. A favourite application in the United States of America to inflamed and excoriated surfaces, bed sores, burns, &c.

Plaster of Mel′ilot. Syn. Emplastrum meliloti, E. è meliloto, L. Prep. 1. (Ph. E. 1744.) Fresh melilot, chopped small, 6 lbs.; suet, 3 lbs.; boil until crisp, strain with pressure, and add, of yellow resin, 8 lbs.; beeswax, 4 lbs., and boil to a plaster. Stimulant. Used to dress blisters, &c. The greater portion of this plaster in the shops is made without the herb, and is coloured with verdigris. (See the next formula.)

2. (Wholesale.) Take of yellow resin, 18 lbs.; green ointment, 4⁄2 lbs.; yellow wax, 3 lbs.; finely powdered verdigris, q. s. to give a deep-green colour.

Plaster, Mercu′′rial. Syn. Emplastrum mercuriale, E. hydrargyri (B. P., Ph. L., E., & D.), L. Prep. 1. (Ph. L.) Add, gradually, of sulphur, 8 gr., to heated olive oil, 1 fl. dr., and stir the mixture constantly with a spatula until they unite; next add of mercury, 3 oz., and triturate until globules are no longer visible; lastly, gradually add of lead plaster (melted over a slow fire), 1 lb., and mix them all well together. (About 1 fl. dr. of balsam of sulphur may be substituted for the oil and sulphur ordered above.) These proportions are the same as those of the B. P.

2. (Ph. E.) Resin, 1 oz.; olive oil, 9 fl. dr.; mix by heat, cool, add of mercury, 3 oz., and triturate until its globules disappear; then add of litharge plaster, 6 oz. (previously liquefied), and mix the whole thoroughly.

3. (Ph. D.) Oil of turpentine, 1 fl. oz.; resin, 2 oz.; dissolve, with the aid of heat; add of mercury, 6 oz.; triturate until the globules disappear, and the mixture assumes a dark grey colour, then add of litharge plaster (previously melted), 12 oz., and stir the whole until it stiffens on cooling.

4. (Wholesale.) Take of mercury, 7 lbs.; prepared serum, ⁄2 lb.; triturate until the globules disappear, and add the mixture to lead plaster (melted by a gentle heat), 36 lbs.; stir them well together, and until they concrete. Very fine bluish-slate or lead colour.

Obs. Mercurial plaster is used as a discutient in glandular enlargements, and other swellings; and is also applied over the hepatic regions in liver complaints.

Plaster, Mercurial, with Belladon′na. Syn. Emplastrum hydrargyri cum belladonnâ, L. Prep. From mercurial plaster, 6 dr.; extract of belladonna, 2 dr.; olive oil, 1 dr.;mixed by a gentle heat. One of our most useful anodyne and discutient applications, in painful scirrhous, scrofulous, and syphilitic tumours. The Medico-Chirurgical Pharm. orders ⁄2 fl. dr. of hydrocyanic acid to be added to every 2 oz. of the above.

Plaster of Mezereon and Cantharides. (Ph. G.) Syn. Emplastrum mezerei cantharidatum. Prep. Cantharides in coarse powder, 3 oz., mezereon cut and dried, 1 oz.; acetic ether, 10 oz. by weight. Macerate for 8 days, filter, and dissolve in the filtered liquid 175 gr. of sandarac, 87 gr. of eleme, 87 gr. of resin, which, spread on silk previously covered with the following solution; isinglass, 2 oz.; distilled water, 20 oz.; rectified spirit, 5 oz. by weight.

Plaster of Min′ium. Syn. Emplastrum minii, E. è minio, E. plumbi oxydi rubri, L. Prep. (Ph. L. 1746.) Olive oil, 4 lbs.; minium (red lead), in fine powder, 2⁄2 lbs.; water, q. s.; proceed as for lead plaster (which it closely resembles).

Obs. To ensure a good colour and the quality of keeping well, the quantity of oil should be increased about 1-3rd. When discoloured by heat it forms the ‘brown minium plaster’ (emp. è minio fuscum) of old pharmacy. Lead plaster, either alone or with the addition of a little red lead, is usually sold for it.

Plaster of Minium (Compound). Syn. Nuremberg Plaster; Emplastrum minii compositum, L.; Emplâtre de Nuremberg, Fr. Prep. (Soubeiran.) Red lead, 12 parts; olive oil, 8 parts; grind them together on a porphyry slab, and add the mixture to lead plaster, 50 parts, beeswax, 24 parts, melted together; lastly, when nearly cold, stir in of camphor, 1 part.

Plaster, Morrison’s Adhesive. Syn. Morrison’s adhesive paste. From wheaten flour, 2 oz.; mild ale, ⁄2 pint; stir them together, and heat the mixture to the boiling point; when cold, add of powdered resin, 3 oz.; and, constantly stirring, again heat them to boiling. Used as a depilatory in ringworm, &c.

Plaster of Mu′cilages. Syn. Diachylon compositum, Emplastrum è mucilaginibus, L. Prep. (Ph. L. 1746.) Beeswax, 20 oz.; oil of mucilages, 4 oz.; melt, and add them to strained ammoniacum, 3 oz.; common turpentine, 1 oz., previously melted together. Stimulant and emollient.

Plaster of Mus′tard. Syn. Emplastrum sinapis, L. This is always an extemporaneous preparation. Flour of mustard is made into a stiff paste with lukewarm water, or with vinegar, and is then spread on a piece of calico or linen (folded two or three times); over the surface of the mustard is placed a piece of gauze or thin muslin, and the plaster is then applied to the part of the body it is intended to medicate. Its action is that of a powerful rubefacient and counter-irritant; but its application should not be continued long, unless in extreme cases. Its effects are often apparently wonderful. We have seen very severe cases of facial neuralgia, sore throat, painful joints, rheumatic pains, &c., relieved in a few minutes by means of a mustard plaster or ‘poultice.’

Plaster, Nuremberg. See Plaster, Minium (Compound).

Plaster of Oak-mistletoe. (Hardy.) Syn. Emplastrum visci quercini. Prep. To 2 parts of melted beeswax add gradually 1 part of juice of true oak mistletoe, and form a plaster. In neuralgic pains.

Plaster of O′′pium. Syn. Emplastrum anodynum, E. opii (B. P., Ph. L. E. & D.), L. Prep. 1. (Ph. L.) Lead plaster, 8 oz.; melt, and add of frankincense (thus), 2 oz.; next, add of extract of opium, 1 oz., previously dissolved in boiling water, 1 fl. oz.; and, constantly stirring, evaporate the mixture over a slow fire to a proper consistence. This plaster is much stronger than that of the Ph. L. 1836 and of the other British Colleges.

2. (Ph. L. 1836.) Lead plaster, 1 lb.; melt, add of powdered thus, 3 oz.; mix, and further add, of powdered opium, ⁄2 oz., water, 8 fl. oz., and boil to a proper consistence.

3. (Ph. E.) Litharge plaster, 12 oz.; Burgundy pitch, 3 oz.; liquefy by heat, then add, by degrees, of powdered opium, ⁄2 oz., and mix them thoroughly. This and the preceding contains only 1-3rd part of the opium ordered in the present Ph. L. & D.

4. (Ph. D.) Resin plaster, 9 oz.; opium, in fine powder, 1 oz.; as the last. Same as B. P.

5. (Ph. B.), Powdered opium, 1 oz.; resin plaster, 9 oz.; melt the plaster and add the opium.

Obs. The above plaster is reputed anodyne, and useful in various local pains; but its virtues in this way have been greatly exaggerated. The formula of the Ph. L. 1836, from being less costly, is still often employed in place of that of the Ph. L. 1851. The following is commonly used:—Lead plaster, 14 lbs.; yellow resin, 2 lbs.; powdered opium, ⁄2 lb.

Plaster of Opium and Camphor. (Dr Paris.) Syn. Emplastrum opii et camphoræ. Prep. Opium and camphor, of each ⁄2 dr. Lead plaster q. s. Mix.

Plaster of Ox′ide of I′ron. Syn. Iron plaster, Frankincense p., Strengthening p.; Emplastrum roborans, E. ferri (B. P., Ph. L. E. & D.), E. thuris, E. ferri oxydi rubri, L. Prep. 1. (Ph. L.) Lead plaster, 8 oz.; frankincense (thus), 2 oz.; melt them together over a slow fire, sprinkle into the mixture sesquioxide of iron, 1 oz., and mix the whole well together.

2. (Ph. E.) Litharge plaster, 3 oz.; yellow resin, 6 dr.; beeswax, 3 dr.; melt them together, then add of red oxide of iron, 1 oz., previously triturated with olive oil, 3⁄2 fl. dr.

3. (Ph. D.) Litharge plaster, 8 oz.; Burgundy pitch, 2 oz.; peroxide of iron, in fine powder, 1 oz.; as No. 1. Same as B. P.

4. (Wholesale.) From lead plaster (quite dry), 84 lbs.; powdered yellow resin, 14 lbs.; ‘crocus martis’ (lively coloured), 14 lbs.; olive oil, 3 pints; as No. 2.

5. (B. P.) Add hydrated peroxide of iron in fine powder, 1 oz., to Burgundy pitch, 2 oz., and litharge plaster, 8 oz., previously melted together, and stir the mixture constantly till it stiffens on cooling.

Obs. Iron plaster is reputed strengthening and stimulant. It is employed as a mechanical support in muscular relaxation, weakness of the joints, &c., especially by public dancers. Its tonic action is probably wholly imaginary. No. 4 is the ‘EMPLASTRUM ROBORANS’ of the shops at the present time.

Plaster, Oxycro′ceum. Syn. Emplastrum oxycroceum, L. Prep. 1. (Ph. E. 1744.) Beeswax, 1 lb.; black pitch and strained galbanum, of each ⁄2 lb.; melt, and add of Venice turpentine, powdered myrrh, and olibanum, of each 3 oz.; powdered saffron, 2 oz.

2. (Wholesale.) From black pitch, 9 lbs.; black resin, 11 lbs.; beeswax and lard, of each 2⁄2 lbs.; melted together. Warm; discutient. Still popular with the lower orders. The saffron of the original formula never finds its way into the oxycroceum plaster of the druggists.

Plaster, Palm. Syn. Emplastrum diapalmum, L.; Diapalme, Emplâtre diapalme, Fr. Prep. (P. Cod.) Lead plaster, 32 parts; yellow wax, 2 parts; melt them together, add of sulphate of zinc, 1 part, dissolve in a little water, and continue the heat, with constant agitation, until all the water is evaporated.

Obs. This plaster originally contained palm oil, and this ingredient is still ordered in the formulæ of Plenck and Reuss. Soubeiran directs white wax to be employed.

Plaster, Paracelsus’s. Syn. Emplastrum Paracelsi, E. stypticum, L. Prep. From lead plaster, 28 lbs.; galbanum plaster, 2 lbs.; powdered white canella and gum thus, of each 1⁄2 lb.; melted together. The original formula, as well as that of the Ph. L. 1721 were similar, although much more complicated.

Plaster of Pitch. Syn. Poor man’s plaster, Gout p., Anti-rheumatic p.; Emplastrum pauperis, E. antirheumaticum, E. antarthriticum, E. picis commune, L. This has been already noticed under the head of Resin Paper. It is also, but less frequently, spread on cloth and leather.

Plaster, Prestat’s Adhe′sive. Prep. From lead plaster, 2⁄2 lbs.; yellow resin, 5 oz.; Venice turpentine, 4 oz.; gum ammoniacum and mastic, of each 1⁄4 oz.; made into a plaster, and spread on linen or calico.

Plaster of Red Lead. See Plaster of Minium.

Plaster of Res′in. Syn. Adhesive plaster, Resinous p.; Emplastrum adhesivum, E. resinæ (B. P., Ph. L. & D.), E. resinosum (Ph. E.), E. lythargyri cum resinâ, L. Prep. 1. (Ph. L.) To lead plaster, 3 lbs., melted by a gentle heat, add of resin, ⁄2 lb., also liquefied by heat, and mix. The formula of the Ph. U. S. is similar.

2. (Ph. E.) Litharge plaster, 5 oz.; resin, 1 oz.; mix with a moderate heat.

3. (Ph. D.) To litharge plaster, 2 lbs., melted by a gentle heat, add, of powdered resin, 4 oz., Castile soap, in powder, 2 oz., and mix them intimately.

4. (Wholesale.) Pale lead plaster (from a previous batch, and quite dry), 72 lbs.; olive oil (Genoa), 3 lbs.; melt them together in a bright and perfectly clean copper pan, and sift in of pale yellow resin (in powder), 12 lbs., stirring all the while. The mixture is to be cooled, and ‘pulled’ or ‘worked,’ after the manner of lead plaster.

5. (B. P.) Resin (in powder), 2; litharge plaster, 16; hard soap, 1; melt the plaster with a gentle heat, add the resin and soap, first liquefied, and mix.

Obs. Resin plaster, spread upon calico, forms the well-known ‘STRAPPING’ or ‘ADHESIVE PLASTER’ so extensively used to protect raw surfaces, support parts, and for dressing ulcers, retaining the lips of recent cuts and wounds in contact, &c. It is gently stimulant, and is thought to assist the healing process. It is also employed as a basis for other plasters. The ‘HOSPITAL PLASTER’ of certain houses is of this kind. See Plaster of Soap, Compound.

Plaster, Resol′vent. Syn. Emplastrum resolvens, E. ex mixtis quatuor, L. Prep. (P. Cod.) Galbanum, hemlock, mercurial, and soap plasters, equal parts, melted together.

Plaster, Roper’s Royal Bath. Prep. (Cooley.) Strained black pitch, 16 oz.; Burgundy pitch, 10 oz.; tar and beeswax, of each 1 oz.; melt, and, when considerably cooled, add of expressed oil of mace, 2 dr.; croton oil, 1 dr.; and spread the mixture upon heart-shaped pieces of white sheep-skin, without remelting it. Stimulant and counter-irritant; recommended by its proprietor as a cure for all human ailments. The ‘Bath-plaster Pills,’ also prepared by Mr Roper, resemble several of the aperient pills already noticed. (See ‘Anat. of Quackery.’)

Plaster, Scott’s. Prep. From lead plaster, 14 oz.; olive oil and white resin, of each 1 oz.; melted together, and spread on calico.

Plaster, Sharp’s Black. Prep. From olive oil, 5 parts; carbonate of lead, 4 parts; beeswax, 1 part; boiled to a plaster.

Plaster, Simple. See Plaster, Wax.

Plaster of Soap. Syn. Emplastrum è sapone, E. saponis (Ph. L. E. & D.), L. Prep. 1. (Ph. L.) To lead plaster, 3 lbs., melted by a slow heat, add of Castile soap, sliced, ⁄2 lb., resin, 1 oz., both (also) liquefied by heat, and, constantly stirring, evaporate to a proper consistence.

2. (Ph. E.) To litharge plaster, 4 oz., gum plaster, 2 oz., melted together, add of Castile soap, in shavings, 1 oz., and boil a little.

3. (Ph. D.) To litharge plaster, 2⁄2 lbs., melted over a gentle fire, add of Castile soap, in powder, 4 oz., and heat them together (constantly stirring) until they combine.

4. (B. P.) Hard soap (in powder), 6; lead plaster, 36; resin (in powder), 1; to the lead plaster, previously melted, add the soap and the resin, first liquefied, then, constantly stirring, evaporate to a proper consistence.

Obs. Care must be taken to evaporate all the moisture from the above compounds, as, if any is left in the plaster, it turns out crumbly, and does not keep well. Much heat discolours it. (See below.)

Soap plaster is emollient and resolvent, and is used in abrasions and excoriations, and as a dressing to soft corns, lymphatic tumours, &c.

Plaster of Soap (Camphorated). (P. Cod.) Syn. Emplastrum saponis camphoratum. Soap plaster, 10 oz.; camphor, 48 gr.

Plaster of Soap (Compound). Syn. Emplastrum saponis compositum, E. adhærens, L. Prep. (Ph. D. 1826.) Resin plaster, 3 oz.; soap plaster, 2 oz.; melted together.

Obs. Less emollient, but more stimulant, than the simple plaster. The ‘EMPLASTRUM È MINIO CUM SAPONE’—Ph. E. 1744 was made by melting 1 part of soap with 5 parts of minium plaster. Neither of the above must be put into water. See Plaster of Resin, Ph. D.

Plaster of Soap-ce′rate. Syn. Emplastrum cerati saponis (B. P.). Prep. 1. From soap cerate, heated by means of a water bath until all the moisture is evaporated. Sometimes 2 or 3 dr. each of powdered mastic and gum ammoniacum are added for each pound of cerate. The product is generally spread whilst still warm. Said to be suppurative, resolvent, cooling, and desiccative. See Cerate (soap).

2. (B. P.) Hard soap, 10; beeswax, 12⁄2; oxide of lead (in powder), 15; olive oil, 20; vinegar, 160; boil the vinegar with the oxide over a slow fire, or by a steam bath, constantly stirring them until they unite; then add the soap and boil again in a similar manner until all the moisture is evaporated; lastly, mix with the wax previously dissolved in the oil, and continue the process till the product takes the consistence of a plaster.

Plaster of Squill, Compound. Syn. Emplastrum scillæ compositum. Prep. Galbanum, ⁄2 oz.; soap, ⁄2 oz.; litharge plaster, 2 oz.; melt together, and add opium, 1 dr.; ammoniacum, ⁄2 oz.; vinegar of squills, 3 oz., mixed together; keep them over the fire constantly stirred till they are incorporated.

Plaster, St Andrew’s. Prep. From yellow resin, 8 oz.; gum elemi, 2 oz.; Bordeaux turpentine and oil of the bay-laurel, of each 1 oz.; melted together by a gentle heat. A stimulant, resolvent, and adhesive plaster, once supposed to possess extraordinary virtues.

Plaster, Stick′ing. See Plaster, Court, Plaster of Resin, &c.

Plaster, Stom′ach. See Plaster, Aromatic, &c.

Plaster, Strength′ening. See Plasters of Frankincense and Oxide of Iron.

Plaster, Styp′tic. See Plaster of Oxide of Iron, Paracelsus’s p., &c.

Plaster of Sul′phate of Quinine′. Syn. Emplastrum quiniæ, E. q. disulphatis, L. Prep. 1. Sulphate of quinine, 1 dr.; resin plaster, 1 oz. Applied to the abdomen in intermittents.

2. Sulphate of quinine, 1 dr.; mercurial plaster, 2 oz. In affections of the liver or spleen, following intermittents, applied over the regions of those viscera.

3. Resin plaster, 9 dr.; sulphate of quinine, 1 dr.; camphor and oil of cajeput, of each ⁄2 dr. Applied over the epigastrium as a prophylactic of cholera.

Plaster of Thus. See Plaster of Frankincense.

Plaster of Ver′digris. Syn. Emplastrum æruginis, E. cupri subacetatis, L. Prep. (P. Cod.) Beeswax, 4 parts; Burgundy pitch, 2 parts; melt, add of Venice turpentine and prepared verdigris (in powder), of each 1 part, and stir until the mass is nearly cold. For other formulæ, see Plaster, Corn, &c.

Plaster, Ver′mifuge. Syn. Emplastrum vermifugum, E. anthelminticum, L. Prep. From powdered aloes, 1 dr.; oil of chamomile, 10 drops; croton oil, 2 drops; oil of turpentine, q. s.

Plaster, Vigo’s. Syn. Emplastrum vigonis, L. Prep. (P. Cod.) Lead plaster, 40 oz.; mercury, 12 oz.; liquid styrax, 6 oz.; beeswax, turpentine, and resin, of each 2 oz.; ammoniacum, bdellium, myrrh, and olibanum, of each 5 dr.; saffron, 3 dr.; oil of lavender, 2 dr.; made into a plaster s.a.

Plaster, Warm. See Calefacient plaster, Burgundy pitch p., &c.

Plaster of Wax. Syn. Simple plaster; Emplastrum attrahens, E. simplex (Ph. E.), E. ceræ, L. Prep. 1. (Ph. E.) Beeswax, 3 oz.; suet and yellow resin, of each 2 oz.; melt them together, and stir the mixture briskly until it concretes by cooling.

2. (Ph. L. 1836.) Yellow wax and suet, of each 3 lbs.; yellow resin, 1 lb.; as the last. Intended to be employed as a simple dressing, especially to blistered surfaces. It is now seldom used.

Plaster, White Diach′ylon. See Plaster of Lead.

Plaster, Yellow Diach′ylon. See Plaster of Galbanum.

Plaster, Zinco-lead. Syn. Emplastrum zinco-plumbicum, E. Diapompholygos, L. Prep. (Ph. Suec.) Beeswax, 1 lb; olive oil and graphite (black lead), of each 6 oz.; carbonate of lead, 4 oz.; oxide of zinc (impure), 3 oz.; olibanum, 1⁄2 oz.; boil to a plaster. Astringent and desiccant. Other forms substitute an equal weight of litharge for the graphite.

PLATE. The name is commonly given to gold and silver wrought into instruments or utensils for domestic use.

The cleaning of plate is an important operation in a large establishment, as its durability, and much of its beauty, depend on this being properly done. The common practice of using mercurial plate powder is destructive to both of these, as mercury not only rapidly erodes the surface of silver, but renders it soft, and, in extreme cases, even brittle. The only powder that may be safely used for silver is prepared chalk, of the best quality. For gold, the form of red oxide of iron, known as Jeweller’s Rouge, is the most useful and appropriate.

In his ‘Workshop Receipts’ Mr Spon recommends the following:—“Take an ounce each of cream of tartar, common salt, and alum, and boil in a gallon or more of water. After the plate is taken out and rubbed dry it puts on a beautiful silvery whiteness. Powdered magnesia may be used dry for articles slightly tarnished, but if very dirty it must be used first wet and then dry.”

Chamois leather, a plate brush, or very soft woollen rags, should alone be used to apply them; and their application should be gentle and long continued, rather than the reverse. Dirty plate, after being cleaned with boiling water, may be restored by boiling it in water, each quart of which contains a few grains of carbonate of soda, and about an ounce of prepared chalk, calcined hartshorn, or cuttle-fish bone, in very fine powder. The ebullition sets up a gentle friction, which effects its purpose admirably. The boiled plate, after being dried, is best ‘finished off’ with a piece of soft leather or woollen cloth which has been dipped into the cold mixture of chalk and water, and then dried. The same method answers admirably with German silver, brass, pewter, and all the softer metals. See Powder (Plate), &c.

PLAT′INA. See Platinum.

PLA′′TING. The art of covering copper and other metals with either silver or gold.

Plating is performed in various ways. Sometimes the silver is fluxed on to the surface of the copper by means of a solution of borax, and subsequent exposure in the ‘plating furnace,’ and the compound ingot is then rolled to the requisite thinness between cylinders of polished steel. The common thickness of the silver plate before rolling is equal to about the 1-40th of that of the compound ingot. Sometimes the nobler metal is precipitated from its solutions upon the copper by the action of chemical affinity, or, more frequently, by the agency of electro-chemical decomposition (electro-plating).

The metal employed for plating is a mixture of copper and brass, annealed or hardened, as the case may require. For electro-plated goods, ‘nickel silver’ is now almost invariably employed. See Electrotype, Gilding, Platinising, Silvering, &c.

PLAT′INISING. Metals may be coated with platinum by nearly similar processes to those already referred to under Plating. In the ‘moist way’ vessels of brass, copper, and silver are conveniently platinised in the following manner:—Solid bichloride of platinum, 1 part, is dissolved in water, 100 parts, and to this solution is added of common salt, 8 parts; or, still better, 1 part of ammonio-chloride of platinum and 8 parts of chloride of ammonium are placed in a suitable porcelain vessel, with about 40 parts of water, and the whole heated to ebullition; the vessels or utensils, previously made perfectly bright, are then immersed in the boiling liquid. In a few seconds they generally acquire a brilliant and firmly adhering layer of platinum.

Silver plates for voltaic batteries are commonly platinised by immersing them for a few seconds in a mixture of saturated solution of bichloride of platinum, 1 part; dilute sulphuric acid, 3 parts; water, 4 to 6 parts. Platinum battery plates are covered with a pulverulent deposit of platinum by means of the electrotype.

Platinised asbestos is prepared by dipping asbestos into a solution of bichloride of platinum, or one of the double chlorides of that metal, and then gradually heating it to redness. It is used as a substitute for spongy platinum. See Electrotype, Voltaic electricity.

PLAT′INUM. Pt. Syn. Platina, White gold; Platinum, L. A heavy, greyish-white metal, occurring chiefly in certain of the alluvial districts of Mexico and Brazil, in the Ural mountains of Russia, in Ceylon, and in a few other places. It occurs in nature under the form of grains and small rolled masses, associated with palladium, rhodium, osmium, ruthenium, iridium, and a little iron. It has only been known in Europe since 1748.

Prep. The native alloy of this metal (crude platinum) is acted upon, as far as possible, by nitro-hydrochloric acid containing an excess of hydrochloric acid, and slightly diluted with water, in order to dissolve as small a quantity of iridium as possible; to the deep yellowish-red and high acid solution thus produced ammonium chloride is added, by which nearly the whole of the platinum is thrown down in the state of ammonio-chloride. This substance, after being washed with a little cold water, is dried and heated to redness; the product is spongy metallic platinum. This is made into a thin uniform paste with water, introduced into a slightly conical mould of brass, and subjected to a graduated pressure, by which the water is squeezed out, and the mass rendered at length sufficiently solid to bear handling. It is next dried, very carefully heated to whiteness, and hammered, or subjected to powerful pressure by suitable means, whilst in the heated state. It will now bear forging into a bar, and may afterwards be rolled into plates, or drawn into wire, at pleasure.

Prop., &c. Platinum is one of the heaviest substances known, its sp. gr. being 21·5. It is whiter than iron, harder than silver, infusible in the strongest heat of our furnaces, and melts only when exposed to the highest temperature obtained by Deville’s oxyhydrogen gas furnace. It is unaffected by air, water, and all the ordinary acids, and even its polish is uninjured by the strongest heat of a smith’s forge; aqua regia, however, dissolves it, though with much more difficulty than gold; it is also superficially oxidised by fused hydrate of potassium. Spongy platinum, powdered platinum, and even perfectly clean platinum foil, possess the remarkable property of causing the union of oxygen and hydrogen gases, with more or less elevation of temperature. Platinum is precipitated from its solutions by deoxidising substances under the form of a black powder (platinum black), which has the power of absorbing oxygen, and again imparting it to combustible substances, and thus causing their oxidation. In this way alcohol and pyroxylic spirit may be converted into acetic and formic acids, &c.

Platinum black is simply platinum in a fine state of division, and is readily obtained as follows:—1. A solution of platinic chloride, to which an excess of carbonate of sodium and a quantity of sugar have been added, is boiled until the precipitate which forms after a little time becomes perfectly black, and the supernatant liquid colourless; the black powder is then collected on a filter, washed, and dried by gentle heat.

2. Platinic-ammonium chloride, reduced to very fine powder, is moistened with strong sulphuric acid, and a small piece of zinc is thrust into the mixture; after the whole is reduced to a black powder it is washed, first with hydrochloric acid, and then with pure water, and is, lastly, dried.

3. (Zdrawkowitch.) Platinum black, in a highly active condition, can be obtained, according to the author, by adding 3 to 5 c.c. of solution of perchloride of platinum, drop by drop, to a boiling mixture of 15 c.c. of glycerin and 10 c.c. of solution of caustic potash of 1·08 sp. gr.

4. (Ph. B.) Boil down rapidly, solution of potash, 2 pints, in a silver or clean iron vessel, until there remains a fluid of oily consistence, a drop of which removed on a warm glass rod solidifies on cooling. Pour this into proper moulds, and when solidified and while still warm put it into stoppered bottles.

Platinum, in the state of platinum black, possesses the property of condensing gases, more especially oxygen, into its pores, and afterwards giving it out to various oxidisable substances. When placed in contact with a solution of formic acid it converts it, with copious effervescence, into carbonic acid; alcohol, dropped upon it, becomes changed by oxidation into acetic acid, the rise of temperature being often sufficient to cause inflammation; exposed to a red heat, it shrinks in volume, assumes the appearance of spongy platinum, and, for the most part, loses these peculiarities. That prepared with zinc explodes, when heated, like gunpowder. The spongy platinum is obtained by igniting the ammonium platinic chloride at a red heat.

The salts of platinum are recognised as follows:—Sulphuretted hydrogen throws down from neutral and acid solutions of the platinic salts a blackish-brown precipitate, which is only formed after a time in the cold, but immediately on heating the liquid. Ammonium sulphide also gives a blackish-brown precipitate, which completely redissolves in a large excess of the precipitant, provided the latter contains an excess of sulphur.

Chloride of ammonium and chloride of potassium give yellow crystalline precipitates, insoluble in acids, but soluble in excess of the precipitate, upon the application of heat, and decomposable by heat, with production of spongy platinum. Ammonia and potassium hydrate also give similar precipitates in solutions previously acidulated with hydrochloric acid.

Estim. This may be effected by throwing down the metal in the form of chloride of ammonium and platinum, which, after being washed on a filter with a little weak spirit to which a little of the precipitate has been added, and afterwards with the spirit alone, may be carefully dried at 212° Fahr., and weighed. Or, the precipitate may be ignited in a platinum crucible, and weighed in the state of a spongy platinum. 193·25 gr. of the platinic and ammonium chlorides are equivalent to 98·75 gr. of metallic platinum.

Uses. Platinum is valuable for the formation of crucibles, capsules, and other utensils or instruments intended to be exposed to a strong heat, or to the action of acids. Platinic chloride and the platinic and sodium chloride are much used in chemical analysis. Both of these are also used in medicines with the same intentions, and in the same doses, as the corresponding salts of gold. These compounds are poisonous. The antidotes and treatment are similar to those described under Gold.

Concluding Remarks.—Daville and Debray have introduced a method of refining platinum, which has already done much to extend the useful applications of the metal. The process consists in submitting the crude metal to the action of an intensely high temperature, obtained by the combustion of hydrogen (or coal-gas) with oxygen, in a crucible of lime. By this means large quantities of platinum (50 lbs. or more) can be kept fused until the sulphur, phosphorus, arsenic, and osmium, generally occurring in crude platinum, are oxidised and volatilised, and the iron and copper are oxidised and absorbed by the lime forming the crucible. At the International Exhibition of 1862 an ingot of pure platinum, weighing over 2 cwt., was exhibited by Messrs Johnson & Mathey, as an illustration of the practical results of this process.

Platinic Chloride. PtCl4. Syn. Bichloride of platinum, Chloride of platinum, Perchloride of p.; Platini bichloridum (Ph. L.), L. Platini Tetrachloridum. Prep. By dissolving platinum in nitro-hydrochloric acid, and evaporating the solution to dryness at a gentle heat. Prop., &c. Reddish-brown, deliquescent, and very soluble in both water and alcohol, yielding orange-coloured solutions. It combines with a variety of metallic chlorides to form ‘double salts.’ Used as a test in chemical analysis, and as an alterative in secondary syphilis, &c.—Dose, ⁄16 to ⁄4 gr., dissolved in distilled water, or made into a pill with syrup and liquorice powder. Some persons prescribe much larger doses, but unsafely. Hoefer recommends an ointment made with it as an application to indolent ulcers. In doses of 5 gr. and upwards it acts as a violent caustic poison. This last salt is the ‘chloride of platinum’ of the shops, and the one used in the arts and medicine. It forms one of the tests included in the Appendix to the Ph. L.

Platinic-Ammonium Chloride. Pt(NH4)2Cl6, or PtCl4 2NH4Cl. Syn. Ammonio-chloride of platinum, Platino-chloride of ammonium. Prep. A solution of chloride of ammonium is added to a strong solution of platinic chloride, and the precipitate washed with dilute alcohol.

Prop. Minute, transparent, yellow octahedral crystals very feebly soluble in water, less so in dilute alcohol, and insoluble in acids; heat converts it into spongy platinum.

Platinic-Potassium Chloride. PtK2Cl6, or PtCl42KCl. Syn. Platino-chloride of potassium, Potassio-Chloride of platinum. Prep. A bright yellow, crystalline precipitate, formed whenever solutions of the chlorides of platinum and of potassium are mixed; or a salt of potassium, acidulated with a little hydrochloric acid, is added to platinic chloride. In appearance, solubility, &c., it closely resembles ammonio-chloride of platinum.

Platinic-Sodium Chloride. PtNa2Cl6, or PtCl42NaCl. Syn. Chloride of platinum and sodium, Sodio-chloride of platinum, Platino-bichloride of sodium; Platini et sodii chloridum, Platini sodio-chloridium, &c., L. Prep. (Redwood.) Platinic chloride, 17 parts; chloride of sodium, 6 parts; dissolve the two salts separately in water, q. s., mix the solutions, and evaporate, that crystals may form. The crystals are large, transparent, and of a yellow-red colour.—Dose, ⁄12 to ⁄2 gr.; in the same cases as the bichloride.

Platinic Oxide. PtO2. Syn. Binoxide of platinum. Prep. 1. By exactly decomposing the platinic sulphate with nitrate of barium, and adding pure hydrate of sodium to the filtered solution, so as to precipitate only half the oxide. (Berzelius.)—2. By boiling platinic chloride with hydrate of sodium, in considerable excess, and then adding acetic acid.

Prop., &c. As the hydrate (Pt(HO)4), it is a bulky brownish powder; this, when gently heated, becomes black and anhydrous. It forms salts with the acids, and combines with some of the bases. The salts have a red or yellow colour, and a remarkable tendency to form double salts with the alkaline salts.

Obs. Both the oxides of platinum are reduced to the metallic state on ignition.

Platinous Oxide. PtO. Syn. Oxide of platinum. Prep. By heating to below redness the platinic chloride and digesting with hydrate of potassium the residue.

Prop., &c. A black powder, soluble in excess of alkali, and freely so in the acids, forming brown solutions of the platinous salts. These are distinguished from solutions of the platinic salts by not being precipitated by chloride of ammonium. Platinous oxalate, in fine copper-coloured needles, may be obtained by heating platinic oxide in a solution of oxalic acid.

Platinum Gas. Syn. Gaz-platine; Gillard’s gas. In Paris this gas is employed by gold- and silversmiths and electro-platers because it gives rise to no sulphur product and burns without giving off soot or smoke. It is free from smell. Steam is decomposed by being made to pass through a retort filled with red-hot charcoal. The hydrogen being freed from the carbonic acid which is associated with it, by means of crystallised carbonate of soda, is burnt from an Argand burner provided with numerous small holes. The flame, which is not luminous in itself, is surrounded by a network of moderately fine platinum wire, which on becoming white-hot becomes luminous. It burns quite steadily, and its illuminating power is said to exceed slightly that of coal gas.

Platinum, Spongy. Prep. 1. By heating ammonio-chloride of platinum to redness.

2. Crude bichloride of platinum and chloride of ammonium are separately dissolved in proof spirit, and the one solution added to the other as long as a precipitate forms; this is collected, and, whilst still moist, formed into little balls or pieces, which are then dried, and gradually heated to redness.

Prop., &c. These have been noticed above. Small balls of spongy platinum are used for the hydrogen instantaneous-light lamp (Döbereiner’s lamp); but they are apt to absorb moisture from the atmosphere, and then lose their power of inflaming hydrogen, until they are re-dried and heated.

PLEURISY. Inflammation of the pleura, or membrane covering the lungs. The symptoms of pleurisy are a sharp pain in the side, which is rendered more acute when a deep breath is taken; quick, short, difficult inspiration; a quick pulse; and fever. Much pain is also experienced if the attempt be made to lie on the affected side.

Pleurisy sometimes accompanies pneumonia or inflammation of the substance of the lungs. If allowed to run on, the disease produces effusion of serum or of lymph into the cavity of the chest, in either case giving rise to adhesions, which cause embarrassment of breathing. On the contrary, it may terminate by resolution or complete recovery.

Pleurisy generally arises from exposure to the cold. A blow or a wound will also cause it, and a not uncommon origin is the splintered end of a broken rib. In every case the advice of the medical practitioner should be sought upon the first indications of the disease. The following treatment is suggested for adoption only by emigrants, or others unable to procure the services of the medical man in cases of urgency:—

Under these circumstances the patient, sitting in an upright posture, should be bled until he is able to breathe without feeling pain. If after bleeding the pain should return, leeches, if obtainable, should be applied to the painful part, and a large blister should be placed near the affected spot. After being bled the patient should have a hot bath. Should the pain not subside, leeching must be had free recourse to, or blood be drawn by cupping. A brisk purgative should be given at the commencement of the disease, and after this has ceased acting the patient should take two grains of calomel and a quarter of a grain of opium every four hours, but this treatment must not be continued longer than is necessary. The patient should remain in bed in a room which has a uniform temperature of 60° F., and adopt a low diet.

In Horses.—Symptoms. Fever, indicated by shivering, indisposition to move or turn, quick pulse, painful cough, and hurried respiration.

“Place the animal without delay in a cool, airy, loose box, and bleed to the extent of seven or eight quarts, or until the pulse falters. Bleeding is never justifiable after the third day, when the pulse reaches 70. Three or four drachms of aloes in solution will suffice for the horse, and clysters must also be given. Until the physic operates sedatives must be used with great caution. Twenty minims of Flemming’s tincture of aconite should be given every three hours.

“Towards the close of the second day the aconite may be discontinued, and a scruple of calomel and a drachm of opium given in a bolus, and repeated every four hours until four or five doses have been given. Apply liniment of ammonia or mustard to the sides. If the animal be thirsty give water in which nitre has been dissolved. Keep the animal perfectly quiet, and let it have soft laxative food.” (Finlay Dun.)

PLUG′GING. The introduction of a mass of lint, sponge, or other suitable material, into a wound or cavity, with the intention of arresting hæmorrhage. It is now seldom adopted, except in cases of bleeding from the nose, and that only after more approved methods have failed.

PLUM. A name applied to several varieties of the Prunus domesticus (Linn.), or wild plum. Among the cultivated varieties, the damson, greengage, French plum, magnum bonum or Mogul p., mirabelle p., Orleans p., and prune, are those best known. Grocers’ ‘plums’ are raisins, or dried grapes.

In the following table will be found the composition of the principal varieties of plum.

Mirabelle, common yellow. Greengage. Black- blue, middle- sized Plums. Dark black- red Plums. Mussel Plums.

Yellow- green, middle size. Large green, very sweet. Common. Italian, very sweet.

Soluble matter—

Sugar 3·584 2·960 3·405 1·996 2·252 5·793 6·730

Free acid,
reduced
to equivalent
in malic acid 0·582 0·960 0·870 1·270 1·331 0·952 0·841

Albuminous substances 0·197 0·477 0·401 0·400 0·426 0·785 0·832

Pectous substances, &c. 5·772 10·475 11·074 2·313 5·851 3·646 4·105

Ash 0·570 0·318 0·398 0·496 0·553 0·734 0·590

Insoluble matter—

Seeds 5·780 3·250 2·852 4·190 3·329 3·540 3·124

Skins, &c. 0·179 0·680 1·035 0·509 1·020 1·990 0·972

Pectose 1·080 0·010 0·245 0·630 1·534

[Ash from insoluble matter included on weights given] [0·082] [0·039] [0·037] [0·041] [0·063] [0·094] [0·066]

Water 82·256 80·841 79·720 88·751 85·238 81·930 81·272

100·00 99·971 100·00 99·925 100·00 100·00 100·00

PLUMBA′GO. Syn. Graphite, Black-lead. One of the native forms of carbon. It contains from 95 to 100% of pure carbon; has a metallic lustre, and conducts electricity nearly as well as the metals. It was formerly regarded as a carbide of iron, but the iron generally found is now known to be merely in a state of mixture. There are two distinct varieties of graphite—crystallised or foliated graphite, obtained chiefly from Ceylon; and amorphous graphite (the ordinary plumbago or black-lead), largely imported to this country from Germany. The Borrowdale mine in Cumberland, from which the finest black-lead was formerly derived, is now nearly exhausted. The foliated graphite of Ceylon and other parts is the principal material employed for making plumbago crucibles and other fire-resisting goods. The amorphous graphite is used for making black-lead pencils, polishing powder for stoves and grates (‘lustre,’ ‘servants’ friend,’ &c.), and to diminish friction in heavy machinery (anti-friction powder). Its powder is also used to give conducting surfaces to articles on which it is desired to deposit copper by the electrotype. In medicine plumbago has been used with apparent advantage in herpes and several chronic skin diseases—externally, as an ointment made with four times its weight of lard; and internally, made into pills.

Purification. For medical and chemical use graphite may be treated as follows:—

1. (Dumas and Stas.) Heat it to redness with caustic potassa, in a covered crucible, then wash it well with water, boil it in nitric acid and in aqua regia, again wash it with water, dry it, and expose it at a white heat to a stream of dry chlorine gas; lastly, wash it with water, and again heat it to dull redness. In analysis.

2. (Ph. Bor.) Pure native plumbago, 1 lb., is boiled in water for 1 hour, then drained, and digested for 24 hours in a mixture of water, 8 oz.; nitric acid and hydrochloric acid, of each 2 oz.; it is, lastly, well washed with water, and dried.

3. (Brodie’s patent.) This process is only applicable to the hard varieties of graphite, as that of Ceylon. It consists in introducing coarsely powdered graphite, previously mixed with ⁄14th of its weight of chlorate of potassa, into 2 parts of concentrated sulphuric acid, which is heated in a water bath until the evolution of acid fumes ceases. The acid is then removed by water, and the graphite dried. Thus prepared, this substance, when heated to a temperature approaching a red heat, swells up to a voluminous mass of finely divided graphite. This powder, which is quite free from grit, may be afterwards consolidated by pressure, and used for making pencils or other purposes.

PLUM′BIC ACID. Binoxide of lead occasionally receives this name on account of its combining with some of the bases to form compounds which have been called plumbates.

PLUM′BUM COR′NEUM. See Lead, Chloride of.

PLUM′OSE AL′UM. The old name of the silky amianthine crystals of the double sulphate of aluminum and iron occasionally found on alum slate. Asbestos has also been so called.

PLUNKET’S CANCER REMEDY. See Caustic, Plunket’s.

PNEUMONIA. Inflammation of the substance of the lungs. When the inflammation extends to the pleura, or covering of the lungs, the disease is distinguished as Pleuro-pneumonia. By most pathologists pneumonia is described under the three general heads of—(1) Croupous pneumonia, (2) catarrhal pneumonia, (3) chronic pneumonia, each of which have, by some medical writers, been subdivided into other forms and varieties.

1. Acute croupous pneumonia. This first description of pneumonia is most common amongst persons of from twenty to thirty years of age, although no age escapes it, and it is generally very severe in character when it attacks the very young or old. It prevails more amongst men than women, since the former, from their more frequent exposure to the weather and to changes of temperature, run greater risk of being overtaken by a very fertile cause of croupal pneumonia, viz. a sudden chill when the body is unusually heated.

It frequently seizes those suffering from chronic or acute disorders, as well as those who are intemperate and drunken. It often assails patients suffering from contagious and acute maladies, such as measles, smallpox, pyæmia, puerperal fever, typhus, and as appears from the accounts of the recent outbreak of Astrakan plague in that disease also. It likewise frequently prevails amongst the poor and badly fed living in the overcrowded quarters of large towns and cities.

The following are the principal symptoms of acute croupous pneumonia, given by Dr Roberts:—

“In some cases there are premonitory signs of general indisposition for a short time. In primary, or unmixed pneumonia, the attack sets in usually very suddenly, the invasion being attended with a single, severe, more or less prolonged rigor. There may be great prostration with fever; vomiting or nervous symptoms, viz. headache, delirium, restless stupor, or, in children, convulsions. The special symptoms are local and general.

“Local symptoms.—Pain in the side is usually present, commonly stabbing or piercing, increased by a deep breath. Difficulty of breathing. Cough also commences speedily; it does not come on in violent paroxysms, but is short and hacking and difficult to repress. Soon expectoration occurs, the expectorated matter presenting peculiar characters. It is scarcely at all frothy but extremely viscid and adhesive, and the vessel which contains it may often be overturned without its escaping. The expectorated matter has a rusty colour or presents various tints of red, from admixture of blood, and as the case progresses, changes of colour are observed through shades of yellow, until finally they become merely like the expectoration of bronchitis. In some cases of croupal pneumonia pain and other symptoms are sometimes very slight or absent, and the expectoration may be merely like that in bronchitis, absent, or in low cases present the appearance of a dark, offensive, thin fluid, resembling liquorice or prune juice.

“General symptoms.—These may be summed up generally as severe fever with great depression and prostration. The skin is hot, dry, and burning. The temperature rises with great rapidity to 102°, 103°, 105°, or sometimes higher. It has been known to reach 107° in cases which recovered, and in fatal cases it has attained to 109·4°. In a large number of instances it does not exceed 104°. There is usually considerable flushing of the cheeks. The pulse ranges generally from 90 to 120, or may be much above this.”

In the majority of cases this variety of pneumonia has a favorable termination, but however slight the form in which it shows itself, or the mildness of its attack, the properly qualified practitioner should be called in to combat it. We have described the nature and cause of the disease and given the course to be followed in treating it, for the benefit only of the emigrant and others similarly situated. The above comments are meant to apply to the other descriptions of pneumonia, which will be adverted to in the course of the present article.

Treatment to be followed in croupous pneumonia.—Bleeding was formerly had recourse to, but this treatment has either been abandoned of late years, or very rarely practised, the only case in which its moderate employment is recommended being that in which the patient is threatened with death from partial privation or suspension of breath.

Leeches may be applied to the spot in pain, and a large blister near it, but it is preferable to first try the effect of hot fomentations and poultices containing laudanum; or turpentine sprinkled on a warm damp flannel may be tried. A third of a grain of tartarised antimony, with a few drops of laudanum, or a third of a grain of hydrochlorate of morphia may be given every four hours.

“In all low forms of the disease the only chance is in free stimulation. At the same times full doses of carbonate of ammonia, with bark, spirits of chloroform, ether, camphor, and such remedies, must be administered. In some cases quinine with iron is useful.”

The best diet consists of milk and beef tea. The patient, it is needless to say, should be kept in bed, and the temperature of his chamber should be maintained at about 60° F. It is also most essential that the room should be thoroughly ventilated, and all the expectorated matter, stools, &c., thoroughly disinfected before removal.

2. Catarrhal pneumonia. The acute variety of this form of pneumonia is that which principally attacks infants and children, and frequently complicates diphtheria, hooping-cough, measles, and influenza; although it may occasionally occur when not associated with these diseases.

In the other variety—chronic catarrhal pneumonia—the greater number of cases arise from bronchitis. Many authorities look upon the last variety of pneumonia as the cause of a great proportion of the cases of pulmonary phthisis.

Symptoms.—These differ, in the great majority of cases, from croupal pneumonia, in not being preceded by rigors. There is always fever and a rise of bodily temperature from 103° to 105°. There is often copious perspiration and increased pulse. As the disease progresses the breathing becomes more difficult and rapid, the cough changes its character, and “becomes short, harsh, hacking, and painful, the child endeavouring to repress it, and having an expression of pain or crying and diminished expectoration.”

The treatment of this form of pneumonia consists in keeping up the strength of the patient by means of good nourishing food, and stimulants judiciously administered. Ammonia and senega should be given if the sufferer is very weak. In ordinary cases ipecacuanha wine will be found useful. Poultices of linseed or mustard to the chest are also prescribed. During convalescence the patient requires careful watching; his diet should be generous, and should include wine; cod-liver oil, quinine, and iron, or other tonics are additionally necessary.

3. Chronic pneumonia. This disease, in which the substance of the lung is in a more or less abnormal or altered condition, is mostly the result of some previous pulmonary affection. It frequently follows successive attacks of the catarrhal variety of pneumonia and the bronchial irritation arising from the inhalation of small particles of dust given off by substances employed in certain occupations or manufactures, such as coal, steel, granite, &c.

The symptoms are pains in the side, cough, sometimes occurring in severe paroxysms, shortness of breathing, the patient meantime gradually becoming thinner and weaker. Sometimes night sweats occur, but generally there is little or no fever.

The best treatment is nourishing diet, combined with tonics and cod-liver oil.

Of late years the doctrine of the contagious nature of some forms of acute pneumonia (whether complicated with pleurisy or not) seems to have been gaining ground amongst medical practitioners. The well-known fact that the pleuro-pneumonia of cattle is propagated by contagion, if it does not prove this contention, is at any rate “worthy,” as Dr Parkes remarks, “of all attention.”

The following cases, selected from amongst many others equally striking, would appear to lend considerable support to this view:

1. The ‘Lancet’ for January 9th, 1862, contains a communication from Dr Bryson, describing an epidemic of pleuro-pneumonia which occurred in 1860 amongst the Mediterranean fleet. The infectious character of the disease is stated to have been very marked; besides which there were several points of resemblance between it and the pleuro-pneumonia which attacks cattle.

2. Professor Bock of Christiana has recorded an outbreak of pneumonia which took place in the Akerhus prison of that city in 1866. Out of 360 prisoners 62 of them were attacked with pneumonia in six months. The prison, like the cattle sheds, ravaged by pleuro-pneumonia, was badly ventilated and overcrowded.

The following illustrations are extracted from Dr Wynter Blyth’s valuable ‘Dictionary of Hygiene and Public Health.’

1. “Mr Alfred Mayo, Mildenhall, Suffolk, in a private letter to the author, gives a series of cases in which the infectious character of the malady was well marked. The first case was that of a bricklayer, about thirty-five years of age, who was taken ill with pleuro-pneumonia. His mother, who nursed him, very shortly afterwards took the same disease and died. A neighbour, a healthy young woman over thirty, who came in to nurse the last patient, was also taken similarly ill, and died with all the physical and other signs and symptoms well developed; and lastly, her child contracted the disease, but eventually recovered. There were other cases in the neighbourhood at the same time, and all of them were remarkable for their fatality.”

2. “Dr Richard Budd, of Barnstaple, has communicated to the author the following remarkable cases:—1. A clergyman, after attending a public meeting, became affected with acute pneumonia. 2. The nurse in attendance became ill of the same disease about a week afterwards. 3. The clergyman’s sister, taking the place of the nurse, was in her turn also seized with pneumonia. 4. A brother of the clergyman, who now undertook the duty of nurse, was in a very short time laid up with the same malady. The nurse and sister died, the two brothers recovered. Dr Budd concludes his communications as follows: ‘Since that time I have witnessed innumerable instances of the occurrence of this disorder in several members of the same family in succession, and I am thoroughly convinced that it spreads by infection, as the facts I have observed admit of no other explanation.’”

The following table, from the Registrar-General’s Report for 1875, gives the yearly number of deaths from pneumonia in England from 1848 to 1875:—

1848 21,868

1849 21,194

1850 20,303

1851 22,001

1852 21,421

1853 24,098

1854 23,523

1855 26,052

1856 22,653

1857 23,452

1858 26,486

1859 24,514

1860 25,264

1861 22,914

1862 23,713

1863 24,181

1864 24,470

1865 22,489

1866 25,155

1867 21,118

1868 19,908

1869 25,246

1870 23,729

1871 22,768

1872 20,282

1873 22,904

1874 25,927

1875 27,161

As a commentary upon the high death-rate from pneumonia for 1875, we may quote the Report for 1877 of the Registrar-General to the President of the Local Government Board. He writes, “The winter of 1875 was unusually severe; extremes of temperature, with a long continuance of east winds, were fatal to infants and to elderly people, and no less than 162,156 deaths were registered in England for the first quarter of the year; the mortality was at the annual rate of 27·5 per 1000, or 2·6 per 1000 above the average of the thirty-eight years—1838-75.”

In animals. For pneumonia and ordinary pleuro-pneumonia, the treatment prescribed for pleurisy may be followed.

Epidemic pleuro-pneumonia of cattle. It is now universally admitted that this disease is very often traceable to contagion, and hence that its propagation has been largely due to the practice of purchasing infected animals in open market, and afterwards allowing them to herd with healthy ones. When a cow is attacked with this epizootic disease, the first noticeable symptoms are generally tenderness and flabbiness of the udder, and a frothy condition of the milk.

These symptoms are accompanied with a dry cough and irregularity of appetite; at the same time the mouth, horns, and legs become hot, the pulse becomes more rapid, and the breathing also. When on its feet the animal arches its back, and when lying down rests itself upon its breast bone. Generally, however, when in the recumbent posture, it lies on that side where the affected lung is.

The treatment, omitting the bleeding, is very similar to that recommended for pleurisy, except that it should be supplemented by the application to the sides of fomentations of hot water, followed by the rubbing in of mustard or of some vesicant. “If no improvement occur after the third or fourth day, give three times daily an ounce each of ginger and gentian, with four drachms of sulphate of iron. Where there is debility, arrested secretion, and cold extremities, give several times a day a quart of warm ale, with an ounce each of ginger, cardamoms, fenugreek, or other aromatics.”

POACH′ING. Amongst cooks, a peculiar method of cooking small articles by a slight boiling or stewing process.

Poached eggs are prepared by breaking them into a small saucepan or stewpan containing about ⁄2 a pint of boiling water, to which a teaspoonful of common salt, and, occasionally, a little vinegar, is added, and gently simmering them for 3 or 4 minutes, or until sufficiently firm to bear removal with a spoon or ‘slice.’ Another method is to employ melted butter instead of water, and to dress them either with or without stirring.

Poached eggs are commonly served on toast, or with fried ham or bacon, with spice or vegetable seasoning at will. They form an excellent breakfast, or ‘make-shift dinner.’

PODOPH′YLLIN. Syn. Resin of podophyllum; Resina podophylli (B. P.). Obtained from the root of the Podophyllum peltatum (Linn.), or may-apple, a substance officinal in the Ph. U. S.

Prep. 1. The alcoholic extract of may-apple is digested in cold ether to remove fatty matter, and is then dissolved in rectified spirit; the solution is decoloured with a little animal charcoal, and filtered; it is, lastly, allowed to evaporate spontaneously.

2. (B. P.) Podophyllum, in coarse powder, 1; rectified spirit, 3⁄4, or a sufficiency; distilled water and hydrochloric acid, of each a sufficiency; exhaust the podophyllum by percolation with the spirit; distil over the spirit; slowly pour the liquid remaining after the distillation of the tincture into three times its volume of water acidulated with ⁄24th part of its weight of hydrochloric acid, constantly stirring; let it stand 24 hours; collect the resin which falls, wash on a filter with distilled water, and dry in a stove. Cholagogue purgative; used as a substitute for calomel.—Dose, ⁄6 to ⁄2 gr., or even 2 gr. It is best to begin with ⁄8 gr. (Squire.)

Prop., &c. An amorphous, greyish-white mass, soluble in alcohol, and slightly soluble in water. It is a safe and certain cathartic, superior in activity to resin of jalap.—Dose, ⁄2 to 3 gr. See Extract of May-apple.

PODOPHYLLUM ROOT. Syn. Podophylli radix (B. P.) The dried rhizome of the Podophyllum peltatum; imported from North America. Active and certain cathartic.—Dose, 10 to 20 gr.

POIS′ON. Syn. Toxicum, Venenum, L. Any substance which, when swallowed or applied in any particular way to the living body, disturbs, suspends, or destroys one or more of the vital functions. In sufficient quantity, or in small doses long continued, the common result of the administration of deleterious substances is either impaired vitality or death.

Poisons are classified by Orfila under four heads:—

1. Irritant poisons, or such as inflame or corrode the parts with which they come in contact. Their chief effects are upon the alimentary canal, with, sometimes, ulceration of the tongue, fauces, and œsophagus. Nausea, vomiting, stomachic and intestinal pains, extreme anxiety and anguish, quick and feeble pulse, cold and clammy skin, and mucous, bilious, or bloody diarrhœa, are among the common leading symptoms. Arsenic, blue vitriol, verdigris, strong acids and alkalies, drastic purgatives, and numerous other substances, belong to this class.

2. Narcotic or Stupefying poisons, or such as paralyse the functions of the nervous system, and produce headache, vertigo, confused vision, delirium, stupor, convulsions, coma, &c. It includes morphia, opium, henbane, oil of bitter almonds, prussic acid, &c.

3. Narcotico-acrid poisons, which produce at the same time narcotism and irritation of the parts which they touch. Alcohol, belladonna, cocculus indicus, colchicum, foxglove, hemlock, poisonous fungi, strychnine, tobacco, veratrine, &c., are of this kind.

4. Septic or Putrefiant poisons, including all those which alter, liquefy, or cause the putrescence of the fluids of the body; as sulphuretted hydrogen, the gas from sewers and cesspools, putrefying organic matter, miasmata, &c.

The treatment of cases of poisoning varies with the substance occasioning it; the proper antidotes will be found noticed under the names of the various substances that exert a deleterious action on the animal body. It may here, however, be useful to remark that, in almost all cases of poisoning, copious vomiting should be excited as soon as possible by the administration of a powerful emetic; its action being promoted by copious draughts of lukewarm water, tickling the throat with the finger, &c. Should this fail, but not otherwise, the stomach-pump should be had recourse to. The vomiting should be kept up and the stomach well washed out with bland albuminous or mucilaginous liquids, such as milk-and-water, barley water, sweetened water, flour-and-water, or any similar matters, as circumstances may afford. After the vomiting a brisk aperient draught, or clyster, may be administered, and nervous irritability or exhaustion allayed by means of ether, opium, wine, or warm spirit-and-water, as the case may require. Even in a suspected case of poisoning, when proper medical advice is not at hand, an emetic should be immediately administered. Vomiting may be, in general, produced very promptly by merely swallowing a cupful of warm water mixed with a teaspoonful of flour of mustard. If no dry mustard is at hand, a portion of the contents of a mustard-pot, put into the water, will answer nearly as well. As mustard may thus prove of so much use, it should never be wanting in any house; but even should there be no mustard at hand, warm water by itself, freely taken, forms a tolerably efficacious emetic.

POLARISA′TION (of Light). A change produced upon light by the action of certain media and surfaces, by which it ceases to present the ordinary phenomena of reflection and transmission. Instruments or apparatus employed to effect this change are called ‘polariscopes.’ Although the polarisation of light is frequently employed as a means of chemical investigation, and is of the utmost interest to the philosophical inquirer, its consideration scarcely comes within the province of this work. See ‘Watt’s Dict. of Chemistry,’ ‘Ganot’s Physics,’ &c.

POL′ISH. Various substances, differing widely from each other, are popularly known under this name. See Powders, Varnish, &c., and below.

Polish, French. See French polish.

Polish, French Reviver. Prep. 1. Linseed oil, ⁄2 pint; pale lac varnish and wood naphtha, of each ⁄4 pint; well shaken together, and again every time before use.

2. Methylated rectified spirit, 3 pints; linseed oil and French polish, of each 1 pint; as the last.

3. Linseed oil (pale), 1 quart; strong distilled vinegar, ⁄2 pint; spirit of turpentine, ⁄4 pint; muriatic acid, 1 oz.

Furniture Cream. Prep. 1. Pearlash, 2 oz.; soft soap, 4 oz.; beeswax, 1 lb.; water, 1 gall.; boil until the whole is united and forms a creamy liquid when cold.

2. Beeswax, ⁄2 lb.; good yellow soap, ⁄4 lb.: water, 5 pints; boil to a proper consistence with constant agitation, then add of boiled oil and spirit of turpentine, of each ⁄2 pint. For use, the above are diluted with water, spread upon the surface with a painter’s brush, and then polished off with a hard brush, cloth, or leather.

3. Boiled oil (pale), ⁄2 pint; beeswax, 1⁄2 oz.; mixed by heat. Applied by a ‘rubber,’ and at once polished off.

4. (For wooden furniture.) White wax, 8 parts; resin, 2 parts; true Venice turpentine, ⁄2 pint; melt at a gentle heat. The warm mass, completely melted, is poured into a stone jar, agitated, and 6 parts of rectified oil of turpentine added thereto. After 24 hours the mass, having the consistency of soft butter, is ready for use. Before using the paste the furniture should be washed with soap and water, and then well dried. (‘Dingler’s Journal.’)

Furniture Oil. See Oils, Mixed.

Furniture Paste. Prep. 1. Oil of turpentine, 1 pint; alkanet root, ⁄4 oz.; digest until sufficiently coloured, then add of beeswax (scraped small), 4 oz.; put the vessel into hot water, and stir until the mixture is complete, then put it into pots. If wanted pale, the alkanet root should be omitted.

2. (White.) White wax, 1 lb.; solution of potassa, ⁄2 gall.; boil to a proper consistence.

Polish, Harness. See Blacking, Harness.

Polish, Leather. See Blacking.

POL′LARD. See Flour.

POL′YCHREST. Syn. Polychrestus, L. A term formerly applied to several medicines on account of the numerous virtues they were supposed to possess. Sal polycrestus is the old name for sulphate of potassa.

POL′YCHROITE. The name formerly given to the colouring matter of saffron, from the variety of colours which it exhibits with different reagents. Its alcoholic and aqueous solutions are of a golden yellow; nitric acid turns it green; sulphuric acid, first blue, and then lilac.

POM′ACE. See Cider.

POMA′TUM. Syn. Pommade, Fr. This term was originally applied to a fragrant ointment prepared with lard and apples; but is now wholly restricted, in this country, to solid greasy substances used in dressing the hair. The pomatums of French pharmacy (POMMADES, GRAISSES MÉDICAMENTEUSES—P. Cod.; LIPAROLÉS—Guibourt; LIPAROLÉS and LIPAROIDÉS—Béral; STEAROLÉS—Chéreau) are soft ointments, having a basis of lard or fat, without resinous matter. See Ointment and Pommade.

POMEGRAN′ATE. The Tunica granatum (Linn.), a small tree indigenous in Persia and the East. Fruit (POMEGRANATE; GRANATA, MALA PUNICA) is cooling and astringent; fruit-rind (POMEGRANATE PEEL; MATACORIUM, CORTEX GRANATI; GRANATUM—Ph. L.) and root-bark (GRANATI RADIX—B. P., Ph. L., E., & D.) are powerfully astringent, detersive, and anthelmintic; the last more particularly so. The double flowers of the wild tree (BALAUSTINES; BALAUSTIÆ), as well as those of the cultivated one (CYTINI), are tonic and astringent.—Dose, 15 to 20 gr. of the root-bark, repeated every 30 or 40 minutes, until four doses have been taken, followed by castor oil; in tapeworm. As an astringent, all the parts described are commonly given under the form of decoction.

POMMADE. [Fr.] The term applied by Continental perfumers to any soft fragrant ointment (POMATUM).

In the preparation of pommades one of the first objects of consideration is to obtain their fatty basis in as fresh and pure a state as possible. Lard, beef, and mutton suet, beef marrow, veal fat, and bear’s fat, are the substances commonly employed for this purpose, either singly or in mixtures of two or more of them. The fat, carefully selected from a young and healthy animal, after being separated from extraneous skin and fibre, is pounded in a marble mortar, in the cold, until all the membranes are completely torn asunder. It is next placed in a covered porcelain or polished metal pan, and submitted to the heat of a water bath, which is continued until its fatty portion has liquefied, and the albuminous and aqueous matter, and other foreign substances, have completely separated and subsided. The liquid fat is then carefully skimmed, and at once passed through a clean flannel filter. In this state it may be aromatised or perfumed at will; after which, when it is intended that the pommade should be opaque and white, it is assiduously stirred or beaten with a glass or wooden knife, or spatula, until it concretes; but when it is desired that it should appear transparent or crystalline, it is allowed to cool very slowly, and without being disturbed. To prevent the accession of rancidity, a little benzoic acid, gum benzoin, or nitric ether may be added to the fat, whilst in the liquid state, as noticed under Fat and Ointment. Sometimes a small portion of white wax or beeswax (according to the intended colour of the product) is melted with the fat to increase its solidity. Some parties employ a few grains of powdered citric acid per ounce, in a like manner, with the intention of increasing the whiteness of the compound; but the practice is not to be commended, as pommades so prepared prove injurious to the hair.

The French perfumers, who are celebrated for the variety and excellence of their pommades, divide them into four classes:—

1. Pommades by infusion. These are made by gently melting in a clean pan, over a water bath, 2 parts of hog’s lard, and 1 part of beef suet (both of the finest quality, and carefully ‘rendered’), and adding thereto one part of the given flowers, previously carefully picked and separated from foreign matter; or, if the odorous substance is a solid, then coarsely bruised, but not reduced to fine powder. The mixture is next digested at a very gentle heat for from 12 to 24 hours, with occasional stirring, the vessel being kept covered as much as possible during the whole time. The next day the mixture is reheated, and again well stirred for a short time, after which it is poured into canvas bags, and these, being securely tied, are submitted to powerful pressure, gradually increased, in a screw or barrel press. This operation is repeated with the same fat and fresh flowers, several times, until the pommade is sufficiently perfumed. A good pommade requires thrice to six times its weight in flowers to be thus consumed; or of the aromatic barks and seeds a corresponding proportion. The pommades of cassia, orange flowers, and several others kept by the French perfumers, are prepared in this manner.

2. Pommades by contact (ENFLEURAGE). These are made by spreading, with a palette knife, simple pommade (made with lard and suet as above) on panes of glass or pewter plates, to the thickness of a finger, and sticking the surface all over with the sweet-scented flowers. These last are renewed daily for one, two, or three months, or until the pommade has become sufficiently perfumed. On the large scale, the panes are placed in small shallow frames, made of four pieces of wood nicely fitted together, and are then closely piled one upon another. On the small scale, pewter plates are generally used, and they are inverted one over the other. In some of the perfumeries of France many thousands of frames are employed at once. The pommades of jasmin, jonquil, orange flowers, narcissus, tuberose, violet, and of some other delicate flowers, are prepared in this manner.

3. Pommades by addition. These are prepared by simply adding the fragrant essences or essential oils, in the required quantity, to the simple pommade of lard and suet to produce the proper odour. In this way the pommades of bergamotte, cédrat, cinnamon, lemons, lemon thyme, lavender, limettes, marjoram, Portugal roses, rosemary, thyme, verbena, and about 40 others kept by the Parisian perfumers, are made.

4. Mixed pommades. Of these a great variety exists, prepared by the addition of judicious combinations of the more esteemed perfumes to simple pommade; or, by the admixture of the different perfumed pommades, whilst in the semi-liquid state. (See below.)

The coloured pommades derive their respective tints from tinctorial matter added to the melted fat before perfuming it. Green is given by gum guaiacum (in powder), or by the green leaves or tops of spinach, parsley, lavender, or walnut;—RED, by alkanet root and carmine;—YELLOW and ORANGE, by annatto or palm oil; WHITE POMMADES are made with mutton suet, instead of beef suet. The BROWN and BLACK hard pomatums, vended under the name of ‘COSMETIQUE,’ are noticed at page 513. A few compound pommades are used as skin cosmetics.

Pommade. Syn. Pomatum. Prep. 1. (Plain pomatum, Simple p.)—a. From lard, 2 lbs.; beef suet, 1 lb.; carefully rendered as above. The ordinary consistence for temperate climates.

b. Lard and suet, equal parts. For warm climates. Both may be scented at will.

2. (Scented pomatum.)—a. Plain pomatum, 1 lb.; melt it by the least possible degree of heat, add of essence of lemon or essence of bergamot, 3 dr.; and stir the mixture until it concretes. This forms the ordinary ‘pomatum’ of the shops.

b. Plain pomatum, 1⁄2 lb.; essence of bergamot, 1⁄2 dr.; essence of lemon, 1 dr.; oils of rosemary and cassia, of each ⁄2 dr.; oil of cloves, 20 drops. More fragrant than the last.

Pommade, Castor Oil. Prep. 1. From castor oil, 1 lb.; white wax, 4 oz.; melt them together; then add, when nearly cold, of essence of bergamot, 3 dr.; oil of lavender (English), ⁄2 dr.; essence of ambergris, 10 drops. Supposed to render the hair glossy.

2. (Crystallised.) From castor oil, 1 lb; spermaceti, 3 oz.; melt them together by a gentle heat, add, of essence of bergamot, 3 dr.; oil of verbena, lavender, and rosemary, of each ⁄2 dr.; pour it into wide-mouthed glass bottles, and allow it to cool very slowly and undisturbed.

Pommade, Castor Oil and Glycerine. (American receipt.) White wax, 1⁄2 oz.; glycerin, 2 oz.; castor oil, 12 oz.; essence of lemon, 5 dr.; essence of bergamot, 2 dr.; oil of lavender, 1 dr.; oil of cloves, 10 drops; annatto, 10 gr.; rectified spirit and distilled water, of each a sufficient quantity. By a moderate heat dissolve the wax in a small portion of the castor oil (one fourth), and triturate it with the remainder of the oil and glycerin till quite cool; then add volatile oils. Lastly, rub the annatto with a drachm of water till smoothly suspended; add a drachm of alcohol, and stir the colouring into the pomade until it is thoroughly mixed. Avoid much heat.

Pommade, Cazenave’s. Prep. From prepared beef marrow, 4 oz.; tincture of cantharides (P. Cod.), 3 to 4 dr.; powdered cinnamon, ⁄2 oz.; melt them together, stir until the spirit has, for the most part, evaporated, then decant the clear portion, and again stir it until it concretes. Recommended as a remedy for baldness and weak hair. It is to be used night and morning; the head being washed with soap-and-water, and afterwards with salt-and-water, before applying it. Dr Cattell scents it with the oils of origanum and bergamot instead of cinnamon.

Pommade, Collante. Prep. 1. Oil of almonds, 3 oz.; white wax, ⁄4 oz.; melt them together, and add, of tincture of mastic (strong), 1 oz.; essence of bergamot, ⁄2 dr. Used to stiffen the hair, and keep it in form.

2. Burgundy pitch (true), 3 oz.; white wax, 2 oz.; lard, 1 oz.; melt, and, when considerably cooled, stir in, of tincture of benzoin, 1 oz.; essence of bergamot, ⁄2 dr. Used to fasten false curls.

Pommade, Cowslip. Prep. From plain pommade, 2 lbs.; essence of bergamot, 3 dr.; essence of lemon and essence of orange peel, of each 1 dr.; huile au jasmin and essence de petit grain, of each ⁄2 dr.; essence of ambergris, 6 drops.

Pommade, Crystallised. Prep. From olive oil and spermaceti, as crystallised castor oil pommade, with scent at will.

Pommade of Cucumbers. Syn. Pommade de Concombres, Unguentum cucumis. Prep. Lard, 10 oz.; veal suet, 6 oz.; balsam of tolu, 9 gr.; rose water, 44 minims; cucumber juice, 12 oz., by weight. Melt the lard and the suet over a water bath, and add the tolu, previously dissolved in a little alcohol, and then the rose water. When clear, decant it into a tinned basin, then add to a third of the cucumber juice, and stir continually for 4 hours; pour off the juice and add another third, stir as before, then pour off, and add the remainder of the juice; separate as much as possible the fat from the liquid, melt by a water bath, and after some hours skim, and put into pots. (Beat, when in a semi-liquid state, with a wooden spatula, when it will become much lighter and nearly double in bulk.)

Pommade d’Alyon. See Ointment of Nitric acid. See Cups.

Pommade de Beauté. Prep. From oil of almonds, 2 oz.; spermaceti, 2 dr.; white wax, 1⁄2 dr.; glycerin, 1 dr.; balsam of Peru, ⁄2 dr.; mixed by a gentle heat. Used as a skin cosmetic as well as for the hair.

Pommade de Casse. Prep. From plain pommade, 1 lb.; palm oil, ⁄2 oz.; melt, pour off the clear, and add oil of cassia and huile au jasmin, of each 1 dr.; neroli, 20 drops; oil of verbena or lemon grass, 15 drops; otto of roses, 5 drops; and stir until nearly cold. Very fragrant.

Pommade d’Hebe. Prep. To white wax, 1 oz., melted by a gentle heat, add, of the juice of lily bulbs and Narbonne honey, each 2 oz.; rose water, 2 dr.; otto of roses, 2 drops. Applied night and morning to remove wrinkles.

Pommade de Ninon de l′Enclos. Prep. Take of oil of almonds, 4 oz.; prepared lard, 3 oz.; juice of houseleek, 3 fl. oz. Used chiefly as a skin cosmetic. Said to be very softening and refreshing.

Pommade Divine. Prep. 1. Washed and purified beef marrow, 2 lbs.; liquid styrax, cypress wood, and powdered orris root, of each 2 oz.; powdered cinnamon, 1 oz.; cloves and nutmegs, of each (bruised) ⁄2 oz.; digest the whole together by the heat of a water bath for six hours, and then strain through flannel.

2. Plain pommade, 2 lbs.; essence of lemon and bergamot, of each 2 dr.; oils of lavender and origanum, of each 1 dr.; oils of verbena, cassia, cloves, and neroli, of each 12 drops; huile au jasmin, 3 dr.; essence of violets, ⁄2 oz.

Pommade, Dupuytren’s. Prep. 1. Take of prepared beef marrow, 12 oz.; melt, add of baume nerval (see Ointment, Nervine), 4 oz.; Peruvian balsam and oil of almonds, of each 3 oz.; and lastly, of alcoholic extract of cantharides, 36 gr.; (dissolve in) rectified spirit, 3 fl. dr. This is the original formula for this celebrated pommade. The following modifications of it are now commonly employed:—

2. (Cap.) Beef marrow, 2 oz.; alcoholic extract of cantharides, 8 gr.; rose oil, 1 dr.; essence of lemons, 30 drops.

3. (Guibourt.) Beef marrow and ‘baume nerval’ (page 1179), of each 1 oz.; rose oil, 1 dr.; alcoholic (or acetic) extract of cantharides, 6 gr.; (dissolved in) rectified spirit, q. s. These compounds are used to promote the growth of the hair and to prevent baldness, for which purpose they are usually coloured and scented according to the taste of the manufacturer. To be useful, they should be well rubbed on the scalp, at least once daily, for several weeks, and the head should be occasionally washed with soap-and-water.

Pommade, East India. Prep. Take of suet, 3 lbs.; lard, 2 lbs.; beeswax (bright), ⁄2 lb.; palm oil, 2 oz.; powdered gum benzoin, 3 oz.; musk (previously triturated with a little lump sugar), 20 gr.; digest the whole together in a covered vessel, by the heat of a water bath, for 2 hours, then decant the clear portion, and add, of essence of lemon, ⁄2 oz.; oil of lavender, ⁄4 oz.; oils of cloves, cassia, and verbena, of each ⁄2 dr. A favourite pommade in the East Indies.

Pommade for Freckles. (‘New York Druggists’ Circular.’) Prep. Citrine ointment and oil of almonds, of each 1 dr.; spermaceti ointment, 6 dr.; oil of roses, 3 drops. Mix well in a wedgwood mortar, using a wooden or bone knife.

Pommade, Hard. Syn. Hard pomatum, Roll p. Prep. 1. Take of beef suet, 2 lbs.; yellow wax, ⁄4 lb.; spermaceti, 1 oz.; powdered benzoin, ⁄4 oz.; melt them together, then add, of oil of lavender, 2 dr.; essence of ambergris, ⁄2 dr. Before it concretes pour it into moulds of paper or tin foil.

2. Mutton suet and lard, of each 1 lb.; white wax, 6 oz.; melt, and add, of essence of lemon, 2 dr.; oil of cassia, ⁄2 dr. Other perfumes may be employed at will.

Hard pomatums are used to gloss and set the hair. They act both as ‘pommade’ and ‘fixateur.’ See Cosmetique.

Pommade, Macassar. Prep. From castor oil, 5 oz.; white wax, 1 oz.; alkanet root, ⁄2 dr.; heat them together until sufficiently coloured, then strain, and add, oil of origanum and oil of rosemary, of each 1 dr.; oil of nutmeg, ⁄2 dr.; otto of roses, 10 drops. Said to be equal in efficacy to MACASSAR OIL.

Pommade, Marechal. Plain pommade scented by digesting it with poudre maréchale.

Pommade, Marrow. Syn. Marrow pomatum. Prep. From prepared beef marrow, ⁄2 lb.; beef suet, ⁄4 lb.; palm oil, ⁄4 oz.; melted together and scented at will.

Pommade, Millefleur. Prep. From plain pommade scented with a mixture of essence of lemon and essence of ambergris, each 4 parts; oil of lavender, 2 parts; oil of cloves and essence de petit grain, of each 1 part; or with other like perfumes so proportioned to each other that no one shall predominate. Much esteemed.

Pommade, Roll. See Pommade, Hard.

Pommade, Roman. See below.

Pommade, Rose. Syn. Rose pomatum. This is plain pommade or hard lard, which has been well beaten with eau de rose, or, better still, scented with otto of roses. It is sometimes tinged with alkanet root.

Pommade, Soft. Plain pomatum scented at will.

Pommade, Soubeiran’s. Prep. From beef marrow, 1⁄2 oz.; oil of almonds, ⁄2 oz.; disulphate of quinine, 1 dr. Recommended for strengthening and restoring the hair.

Pommade, Transparent. Prep. Spermaceti, 2 oz.; castor oil, 5 oz.; alcohol, 5 oz.; oil of bergamot, ⁄2 dr.; oil of Portugal, ⁄2 dr.

Pommade, Vanilla. Syn. Roman pommade, Pommade à la vanille, Pommade Romain. From plain pommade and pommade à la rose, of each 12 lbs.; powdered vanilla, 1 lb.; heat them together in a water bath, stir constantly for 1 hour, let it settle for another hour, decant the clear, and add, oil à la rose, 2⁄2 lbs.; bergamot, 4 oz.

POPPY. Syn. White poppy; Papaver somniferum, L. The capsules or fruit (“mature”—Ph. L.; “not quite ripe”—Ph. E.) form the poppies or poppy-heads of the shops (PAPAVERIS CAPSULÆ; PAPAVER—Ph. L., E., & D.). They are anodyne and narcotic, similar to opium, but in only a very slight degree. The seeds (MAW SEED), which are sweet, oleaginous, and nutritious, are used as a substitute for almonds in confectionery and mixtures, and are pressed for their oil. See Extract, Opium, and Syrup.

Poppy, Red. Syn. Corn poppy, Corn rose; Papaver rhœas, L. The fresh petals or flowers (RHŒADOS PETALA; RHŒAS—Ph. L., E., & D.) are reputed pectoral, but are chiefly employed on account of their rich colour. See Syrup.

POP′ULIN. Syn. Populinum, L. A peculiar neutral, crystallisable substance, formerly supposed to be an alkaloid, found, associated with SALICIN, in the root-bark of the Populus tremula (Linn.), or aspen.

Prep. Concentrate the decoction by a gentle heat, and set it aside in a cool situation to crystallise; dissolve the crystals which are deposited in rectified spirit, decolour them by digestion with animal charcoal, filter, and again crystallise. To render them still purer they may be redissolved and crystallised a second and a third time, if necessary.

Prop., &c. It resembles salicin in appearance and solubility, but, unlike that substance, has a penetrating sweet taste. Dilute acids convert it into benzoic acid, grape sugar, and saliretin; and with a mixture of sulphuric acid and bichromate of potassa it yields a large quantity of salicylous acid. It appears to be tonic, stomachic, and febrifuge.

POR′CELAIN. See Pottery.

PORK. The value of pork as an article of diet is well known. That from the young and properly fed animal is savoury, easy of digestion, and, when only occasionally employed, highly wholesome; but it is apt to disagree with some stomachs, and should, in such cases, be avoided. To render it proper for food, it should be thoroughly but not overcooked. When salted it is less digestible. The frequent use of pork is said to favour obesity, and to occasion disorders of the skin, especially in the sedentary. See Meat.

POR′PHYRIZED, PORPHORIZA′TION. Words coined by recent pharmaceutical writers, and possessing similar meanings to LEVIGATED and LEVIGATION.

PORPHY′ROXIN. A neutral crystallisable substance discovered by Merck in opium. It is soluble in both alcohol and ether, insoluble in water, and is characterised by assuming a purplish-red colour when heated in dilute hydrochloric acid.

PORRI′GO. See Ringworm.

POR′TER. This well-known beverage, now the common drink of the inhabitants of London, by whom it is generally termed ‘beer,’ originated with a brewer named Harwood, in 1722. Previously to this date, ‘ale,’ ‘beer,’ and ‘twopenny,’ constituted the stock in trade of the London publican, and were drunk, either singly or together, under the names of ‘half-and-half’ or ‘three threads,’ for which the vendor was compelled to have recourse to two or three different casks, as the case might demand. The inconvenience and trouble thus incurred led Mr Harwood to endeavour to produce a beer which should possess the flavour of the mixed liquors. In this he succeeded so well that his new beverage rapidly superseded the mixtures then in use, and obtained a general preference among the lower classes of the people. At first this liquor was called ‘entire’ or ‘entire butt,’ on account of it being drawn from one cask only, but it afterwards acquired, at first in derision, the now familiar name of ‘porter,’ in consequence of its general consumption among porters and labourers. The word ‘entire’ is still, however, frequently met with on the signboards of taverns about the metropolis.

The characteristics of pure and wholesome porter are its transparency, lively dark brown colour, and its peculiar bitter and slightly burnt taste. Originally, these qualities were derived from the ‘high-dried malt,’ with which alone it was brewed. It is now generally, if not entirely, made from ‘pale’ or ‘amber malt,’ mixed with a sufficient quantity of ‘patent’ or ‘roasted malt’ to impart the necessary flavour and colour. Formerly, this liquor was ‘vatted’ and ‘stored’ for some time before being sent out to the retailer, but the change in the taste of the public during the last quarter of a century in favour of the mild or new porter has rendered this unnecessary. The best ‘draught porter,’ at the time of its consumption, is now only a few weeks old. In this state only would it be tolerated by the modern beer-drinker. The old and acid beverage that was formerly sold under the name of porter would be rejected at the present day as ‘hard’ and unpleasant, even by the most thirsty votaries of malt liquor.

The ‘beer’ or ‘porter’ of the metropolitan brewers is essentially a weak mild ale, coloured and flavoured with roasted malt. Its richness in sugar and alcohol, on which its stimulating and nutritive properties depend, is hence less than that of an uncoloured mild ale brewed from a like original quantity of malt. For pale malt is assumed to yield 80 to 84 lbs. of saccharine per quarter; whereas the torrefied malt employed by the porter brewers only yields 18 to 24 lbs. per quarter, and much of even this small quantity is altered in its properties, and is incapable of undergoing the vinous fermentation. In the manufacture of porter there is a waste of malt which does not occur in brewing ale; and the consumer must, therefore, either pay a higher price for it or be content with a weaker liquor.

The hygienic properties of porter, for the most part, resemble those of other malt liquors. Some members of the faculty conceive that it is better suited to persons with delicate stomachs and weak digestion than either ale or beer. That there may be some reason for this preference, in such cases, we are not prepared to deny, but undoubtedly, when the intention is to stimulate and nourish the system, ale is preferable. Certain it is, however, that the dark colour and strong taste of porter render its adulteration easier than that of ale, whilst such adulteration is more difficult of detection than in the paler varieties of malt liquors. “For medical purposes, ‘bottled porter’ (CEREVISIA LAGENARIA) is usually preferred to ‘draught porter.’ It is useful as a restorative in the latter stages of fever, and to support the powers of the system after surgical operations, severe accidents, &c.” (Pereira, ii, 982.) When ‘out of condition’ or adulterated, porter, more than perhaps any other malt liquor, is totally unfit for use as a beverage, even for the healthy; and when taken by the invalid, the consequences must necessarily be serious. Dr Ure says that pure porter, “when drank in moderation, is a far wholesomer beverage for the people than the thin acidulous wines of France and Germany.”

The manufacture of porter has been described in our article on Brewing, and is also referred to above. It presents no difficulty or peculiarity beyond the choice of the proper materials. A mixture of ‘brown’ and ‘black malt’ is thought to yield a finer flavour and colour to the pale malt that gives the body to the liquor than when ‘black’ or ‘roasted malt’ is employed alone. The proportion of the former to the latter commonly varies from 1-6th to 1-4th. When ‘black malt’ is alone used, the proportion varies from the 1-10th to 1-15th. 1 lb. of ‘roasted malt,’ mashed with about 79 lbs. of pale malt, is said to be capable of imparting to the liquor the flavour and colour of porter. The following formulæ were formerly commonly employed in London:—

1. (Draught porter.) From pale malt, 3⁄2 q. s.; amber malt, 3 q. s.; brown malt, 1⁄2 q.; mash at twice with 28 and 24 barrels of water, boil with brown Kent hops, 56 lbs., and set with yeast, 40 lbs. Prod. 28 barrels, or 3⁄2 times the malt, besides 20 barrels of table-beer from a third mashing.

2. (Bottling porter; Brown stout.) From pale malt, 2 q. s.; amber and brown malt, of each 1⁄2 qr.; mash at 3 times with 12, 7, and 6 barrels of water, boil with hops, 50 lbs., and set with yeast, 26 lbs. Prod. 17 barrels, or 1⁄2 times the malt.

The purity and quality of porter, as well as of other malt liquors, may be inferred in the manner noticed under Beer; but can only be positively determined by a chemical examination. For this purpose several distinct operations are required:—

1. Richness in ALCOHOL. This may be correctly found by the method of M. Gay-Lussac; or from the boiling point. (See Alcoholometry and Ebullioscope.) The method with anhydrous carbonate of potassa will also give results sufficiently near to the truth for ordinary purposes, when strong or old beer is operated on. The quantity of the liquor tested should be 3600 water grains measure; and it should be well agitated, with free exposure to the air, after weighing it, but before testing it for its alcohol. The weight of alcohol found, multiplied by 1·8587, gives its equivalent in sugar. This may be converted into ‘brewer’s pounds’ or density per barrel, as below.

2. Richness in SACCHARINE or EXTRACTIVE MATTER. A like quantity of the liquor under examination, after being boiled for some time to dissipate its alcohol, is made up with distilled water, so as to be again exactly equal to 3600 water-grains measure. The sp. gr. of the resulting liquid is then taken, and this is reduced to ‘brewers’ pounds’ per barrel, by multiplying its excess of density above that of water (or 1000) by 360, and pointing off the three right-hand figures as decimals.

3. Acetic acid or VINEGAR. This is determined by any of the common methods of ACIDIMETRY (which see; see also Acetimetry). Each grain of anhydrous acetic acid so found represents 1·6765 gr. of sugar.

4. Gravity of ORIGINAL WORT. This is obtained by the addition of the respective quantities of saccharine matter found in Nos. 1, 2, and 3 (above). These results are always slightly under the true original density of the wort, as cane sugar appears to have been taken by the Excise as the basis of their calculations. More correctly, 12% of proof spirit is equivalent to 19 lbs. of saccharine per barrel. 10⁄2 lbs. of saccharine are equiv. to 1 gall. of proof spirit.

5. Detection of NARCOTICS. This may be effected either by the method described under Alkaloid, or by one or other of the following processes:—

a. Half a gallon of the beer under examination is evaporated to dryness in a water bath; the resulting extract is boiled for 30 or 40 minutes in a covered vessel with 10 or 12 fl. oz. of alcohol or strong rectified spirit, the mixture being occasionally stirred with a glass rod, to promote the action of the menstruum; the alcoholic solution is next filtered, treated with a sufficient quantity of solution of diacetate of lead to precipitate colouring matter, and again filtered; the filtrate is treated with a few drops of dilute sulphuric acid, again filtered, and then evaporated to dryness; it may then be tested with any of the usual reagents, either in the solid state, or after being dissolved in distilled water. Or the extract, obtained as above, may be boiled as directed with rectified spirit, the solution filtered, the spirit distilled off, and a small quantity of pure liquor of potassa added to the aqueous residue, which is then to be shaken up with about 1 fl. oz. of ether; lastly, the ethereal solution, which separates and floats on the surface, is decanted, evaporated, and the residuum tested, as before. The alkaline liquid, from which the ether has been decanted, is then separated from any precipitate which may have formed, and both of these separately tested for alkaloids.

b. From 2 to 3 oz. of purified animal charcoal are diffused through ⁄2 gall. of the beer, and is digested in it, with frequent agitation, for from 8 to 12 hours; the liquor is next filtered, and the charcoal collected on the filter is boiled with about ⁄2 pint of rectified spirit; the resulting alcoholic solution is then further treated as above, and tested. This answers well for the detection of strychnia or nux vomica.

6. Picric acid. This substance, which was formerly employed to impart bitterness to London porter in lieu of hops, may be detected as follows:—

a. A portion of the liquor agitated with a little solution of diacetate of lead loses its bitter flavour if it depends on hops, but retains it if it depends on picric acid.

b. Pure beer is decoloured and deodorised by animal charcoal; but beer containing picric acid, when thus treated, retains a lemon-yellow colour and the odour.

c. Unbleached sheep’s wool, boiled for six or ten minutes, and then washed, takes a canary-yellow colour if picric acid be present. The test is so delicate that 1 grain of the adulterant in 150,000 gr. of beer is readily detected.

d. (Vitate.) The author agitates 10 c.c. of the suspected beer in a test tube with half its volume of pure amylic alcohol. If the mixture is left to settle, the amylic stratum separates entirely, and is drawn off with a pipette, evaporated to dryness at a convenient temperature in a porcelain capsule, and the residue is finally taken up in a little distilled water with the aid of heat. The aqueous solution is divided into portions, and submitted to the following reagents. One portion is treated with a solution of ammonio-sulphate of copper, which, in dilute solutions of picric acid, instantly produces a turbidity, due to the formation of very minute crystals of the ammonio-picrate of copper, of a greenish colour. Another portion may be treated with a concentrated solution of cyanide of potassium, which produces a blood-red colour, more or less intense, according to the quantity of picric acid present, in consequence of the formation of iso-purpuric acid. A third portion may be submitted to the action of sulphide of ammonium, rendered still more alkaline by the addition of a few drops of ammonia. Here also a blood-red colour is produced, which becomes more intense on the application of heat, and is due to the formation of picramic acid.

7. Mineral matter.—a. A weighed quantity of pure beer evaporated to dryness, and then incinerated, does not furnish more than from ·20% to ·35% of ash, the quantity varying within these limits with the strength of the liquor and the character of the water used in brewing it.

b. A solution of this ash, made by decoction with distilled water, should be only rendered slightly turbid by solutions of acetate of lead, bichloride of platinum, nitrate of baryta, nitrate of silver, oxalate of ammonia, and sulphuretted hydrogen.

c. If the beer contained common salt, the above solution will give a cloudy white precipitate with a solution of nitrate of silver. Each grain of this precipitate is equivalent to ⁄2 gr. of common salt (nearly).

d. If GREEN COPPERAS (sulphate of iron) is present, ferridcyanide of potassium gives a blue precipitate, and ferrocyanide of potassium a bluish-white one, turning dark blue in the air; solution of chloride of barium gives a white precipitate, each grain of which, after being washed, dried, and ignited, represents 1·188 gr. of crystallised protosulphate of iron.

e. The ash, digested in water slightly acidulated with nitric acid, and then boiled, yields a solution which, when cold, gives a black precipitate with sulphuretted hydrogen, and a white one with dilute sulphuric acid when lead is present.

8. Wittstein’s method for the detection of ADULTERANTS in beer. One litre of the suspected beer is evaporated by a moderate heat to the consistence of a thick syrup. This is poured into a tared glass cylinder capable of containing ten times its volume and weighed; five times its weight of 93° to 95° alcohol is added, and the whole frequently stirred, by means of a thick glass rod, during twenty-four hours.

By this means all the gum, dextrin, sulphates, phosphates, and chlorides are separated, and a comparatively small portion is obtained in solution. After clearing, this solution is decanted, the residue is again treated with fresh alcohol, the two products mixed, filtered, and the alcohol driven off by a gentle heat.

a. Of the syrupy residue left after this evaporation, a small portion is diluted with three times its bulk of water, and tested for picric acid, according to the directions already given.

b. The remaining largest portion of the syrup is agitated for some time with six times its weight of pure colourless benzol (boiling point 80° C.); this is decanted off, and the operation is repeated with fresh benzol, and the two liquors, the first of which has become yellow, the second having scarcely changed colour, are evaporated at a gentle heat. The pale, yellow, resinous residue thus obtained may possibly contain brucine, strychnine, colchicine, or colocynthin. To ascertain this, three portions of the resin are placed on a porcelain capsule; one is treated with nitric acid (sp. gr. 1·33 to 1·40), another with concentrated sulphuric acid, and the third, after a few morsels of red chromate of potash have been added, also with sulphuric acid. A red colour, produced by the nitric acid, indicates brucine with certainty, and a violet colour colchicine; a red colour produced by sulphuric acid indicates colocynthin, and a purple violet, produced by sulphuric acid and bichromate of potash, reveals strychnine. Resin in which one or other of these colorations is produced possesses an extremely bitter taste; that in which the coloration does not take place is also bitter, but the bitterness recalls the well-known hop flavour.

c. The syrup which has been treated with benzol is freed, by gentle heating, from the small quantity of benzol remaining, and agitated twice with pure colourless amylic alcohol (boiling point 132° C.). The first portion of the alcohol acquires a more or less wine or golden-yellow colour. It would take up any picrotoxin or aloes if present, and thereby acquire a strongly bitter taste.

If neither of these two substances be present, the amylic alcohol does not become bitter, because neither the hop bitter nor the remaining four bitter principles—absinthin, gentipicrin, menyanthin, and quassiin—are soluble in it.

In order to distinguish picrotoxin from aloes a portion of the first obtained amylic alcoholic solution is poured upon glass, and allowed to evaporate spontaneously. If a fine white crystallisation be formed picrotoxin is present, if not aloes is present, and can only be recognised by its peculiar, saffron-like odour.

d. The syrup which has been treated with benzol and amylic alcohol is freed by means of blotting paper from the small quantity of amylic alcohol adhering to it, evaporation by heat being impracticable in consequence of the high boiling point of the alcohol, and shaken with anhydrous ether. This takes up the hop bitter yet present and absinthin. After evaporation the latter is easily recognised through its wormwood-like aroma; it also gives a reddish-yellow solution with concentrated sulphuric acid, which changes quickly to an indigo-blue colour.

e. After treating with ether the syrup has yet to be tested for gentipicrin, menyanthin, and quassiin. As it is now free from the hop bitter, a decidedly bitter taste points to one of these three substances. Any remaining ether is removed, and the syrup is dissolved in water and filtered; to one portion is added strong ammoniacal solution of silver, and it is then heated.

If it remains clear quassiin is present; if a silver mirror be formed it originates either with gentipicrin or menyanthin. Another portion is evaporated to dryness on porcelain, and concentrated sulphuric acid added. If, while cold, no change of colour takes place, but on heating it becomes carmine red, gentipicrin is present; menyanthin would give a yellowish-brown colour, gradually changing to violet.

For further information connected with this subject, see Alcoholometry, Ale, Beer, Brewing, Malt liquors, &c.

PORT-FIRE. A paper tube, from 9 to 12 inches in length, filled with a slow-burning composition of metal powder, nitre, and sulphur, rammed moderately hard, by a similar process to that adopted for small rockets. It is used in lieu of a touch-match, to fire guns, mortars, pyrotechnical devices, &c.

PORTLAND CEMENT. A species of mortar formed by calcining a mixture of limestone and argillaceous earth, and grinding the calcined mass to powder, in which state it must be preserved from the air. It is characterised by absorbing a large quantity of water, and then rapidly becoming solid, and, after a time, acquiring considerable hardness. See Mortar and Cement.

POSOL′OGY. See Dose.

POS′SET. Syn. Possetum, L. Milk curdled with wine or any other slightly acidulous liquor. It is usually sweetened with either sugar or treacle, and is taken hot.

Prep. From new milk, ⁄2 pint; sherry or marsala, 1 wine-glassful; treacle, 1 or 2 tablespoonfuls, or q. s.; heat them together in a clean saucepan until the milk coagulates. This is called ‘treacle posset’ or ‘molasses posset,’ and, taken on retiring to rest, is highly esteemed in some parts of the country as a domestic remedy for colds. Lemon juice, strong old ale, or even vinegar, is occasionally substituted for wine, and powdered ginger or nutmeg added at will.

POT METAL. See Cock metal.

POT′ASH. The ‘potash,’ or ‘potashes’ of commerce is an impure carbonate of potassium, so named after the pots or vessels in which it was first made. The ‘potash,’ or ‘potassa,’ of the chemist is the hydrate of a peculiar metal, potassium, which is more particularly referred to below. The word potash is vulgarly applied to the crude or commercial carbonate of potassium. See Carbonate of Potassium, &c.

Potash is now principally obtained from the following sources:—

1. From carnallite, a hydrated double chloride of potassium and magnesium, which occurs associated with other salts of potassium and magnesium, as well as of sodium, in a bed of clay, at Stassfurth, near Madgeburg, in Prussia.

2. Feldspar and similar minerals.

3. Sea water, and the mother-liquor of salt works.

4. Native saltpetre.

5. The ashes of several plants.

6. The calcined residue of the molasses of beet-root sugar remaining after distillation.

7. The seaweeds, as a by-product of the manufacture of iodine.

8. From the fleece of the sheep.

The following is a process for obtaining alkali from seaweed, described in the ‘Chemical News’ for Nov. 10th, 1876:—

At the chemical works at Aalbourg, in Jutland, Denmark, where about 30 tons of alkali are made per week by the ammonia process, Mr Theobald Schmidt, the director of the manufactory, proposes to work, in conjunction with this process, a method devised by himself of treating seaweed so as to obtain iodine, potash, salts, and other marketable products therefrom.

In Denmark a very heavy duty is levied on the importation of common salt, whilst enormous quantities of seaweed rich in iodine and potash can be obtained at small cost in the neighbourhood of the works. Mr Schmidt’s process is as follows:—After the seaweed is dried and burnt, a concentrated solution of the ash is made and added to the liquor, containing chlorides of sodium and calcium, left after the ammonia has been recovered in the ammonia-soda process by boiling with lime. The sulphates of potash, soda, and magnesia, contained in the ash of the seaweed are thereby decomposed, and hydrated sulphate of lime and hydrated magnesia are precipitated in a form which may be available for paper-making, as ‘pearl-hardening.’ The last traces of sulphates are got rid of by adding a small quantity of solution of chloride of barium. To the clear solution nitrate of lead is now added, until all the iodine is precipitated as iodide of lead, which is then separated by filtration and treated for the production of iodine or iodides. After filtration the liquid is boiled; nitrate of soda is added to convert the chloride of potassium present into nitrate of potash. The latter is separated by crystallisation. There remains a solution of common salt, containing traces of ammonia from the previous soda operation, and a trace of chloride of potassium. This solution is again treated by the ordinary ammonia-soda process for the production of bicarbonate of soda and white alkali. See Carbonate of Potassium, &c.

POTAS′SIUM. K. The metallic base of potash. It was discovered, in 1807, by Sir H. Davy, who obtained it by submitting moistened potassium hydrate, under a film of naphtha, to the action of a powerful voltaic current. It has since been procured by easier methods, of which the following, invented by Brunner, is the best.

Prep. An intimate mixture of carbonate of potassium and charcoal is prepared by calcining, in a covered iron pot, the crude tartar of commerce; when cold, it is rubbed to powder, mixed with 1-10th part of charcoal in small lumps, and quickly transferred into a retort of stout hammered iron; the latter may be one of the iron bottles in which quicksilver is imported, a short and somewhat wide iron tube having been fitted to the aperture; the retort, thus charged, is placed upon its side, in a furnace so constructed that the flame of a very strong fire, preferably fed with dry wood, may wrap round it, and maintain every part of it at a very high and uniform degree of heat. A copper receiver, divided in the centre by a diaphragm, is next connected to the iron pipe, and kept cool by the application of ice, whilst the receiver itself is partly filled with mineral naphtha, to preserve the newly formed potassium as it distils over. The arrangement of the apparatus being completed, the fire is gradually raised until the requisite temperature, which is that of full whiteness, is reached, when decomposition of the alkali by the charcoal commences, carbonic acid gas is abundantly disengaged, and potassium distils over, and falls in large drops into the liquid. To render the product absolutely pure, it is redistilled in an iron or green-glass retort, into which some naphtha has been put, that its vapour may expel the air, and prevent the oxidation of the metal. The pieces of charcoal are introduced for the purpose of absorbing the melted carbonate of potassium and preventing its separation from the finely divided carbonaceous matter. Prod. 3% to 4% of the weight of tartar acted on; 1 lb. yielded 280 gr.

Prop., &c. Pure potassium is a brilliant white metal, with a high lustre; at the common temperature of the air it is soft, and may be easily cut with a knife, but at 32° Fahr. it is brittle and crystalline; it melts completely at 136° Fahr., and in close vessels distils unaltered at a low red heat. Sp. gr. ·865. Its most remarkable property is its affinity for oxygen, which is so great that it takes it from most other substances containing it. Exposed to the air, its surface is instantly tarnished, and quickly becomes covered with a crust of oxide or hydrate. It inflames spontaneously when thrown on water, and burns with a beautiful purple or purple-red flame, yielding a pure alkaline solution. It can only be preserved in naphtha, rock oil, or some other fluid hydrocarbon.

The salts of potassium are all soluble in water, the tartrate, periodate, and fluosilicate being the least so; they are usually colourless, unless the acid be coloured, crystallise readily, and form numerous double compounds. They can be recognised as follows:—

Sulphuretted hydrogen, sulphide of ammonium, and carbonate of ammonium, do not affect them. A solution of tartaric acid, added in excess, to moderately strong neutral or alkaline solutions of potassium salts, gives a quickly subsiding, gritty or crystalline, white precipitate, which is redissolved on heating the liquid, and again separates as it cools; and is also soluble in aqueous solutions containing free alkali, or free mineral acids. Platinic chloride produces, in neutral and acid solutions, a yellow crystalline precipitate. Alkaline solutions require to be first slightly acidulated with hydrochloric acid. The separation of the precipitate here, as well as that produced by tartaric acid, is promoted by violent agitation and friction against the sides of the vessel, and the delicacy of both is increased by the addition of some alcohol. When converted into carbonate by igniting with excess of carbonate of ammonium and alcohol, and treated with sulphuretted hydrogen solution and nitro-prusside of sodium, gives a splendid violet colour, turning through red to green on standing.

Potassium salts give with sodium periodate and hydro-fluosilicic acid white precipitates soluble in much water.

Heated in the inner flame of the blow-pipe on platinum wire, they impart a violet coloration, masked, however, by a mere trace of sodium salts.

Potassium, Acetate of. KC2H3O2. Syn. Acetate of potash, Potassic acetate; Potassæ acetas (B. P., Ph. L., E., D.). Prep. (Ph. L.) Acetic acid, 26 fl. oz.; distilled water, 12 fl. oz.; mix, and add, gradually, carbonate of potassium, 1 lb., or q. s. to saturate the acid; next, filter the solution, and evaporate it by the heat of a sand bath, gradually applied, until the salt is dried.

Prop., &c. Acetate of potassium, prepared as above, occurs in shining white masses, having a foliated soft texture, a slight but peculiar odour, and a warm sharp taste; it deliquesces in the air; dissolves in rather less than its own weight of water, and in about twice its weight of alcohol; and by exposure to a red heat is converted into pure carbonate of potassium. In trade it is preserved in well-corked and sealed bottles.

Pur. It is entirely soluble in water, and in rectified spirit. These solutions neither affect litmus nor turmeric, nor are they disturbed by either chloride of barium or nitrate of silver; but if from a stronger solution anything is thrown down by nitrate of silver, the same is again dissolved on the addition of water or dilute nitric acid. Sulphuric acid being added, the vapour of acetic acid is evolved. 100 gr. of this salt, digested in sulphuric acid, the solution evaporated, and the residuum dried at a high temperature, furnish 88·8 gr. of sulphate of potassium.

Uses, &c. Acetate of potassium has been found useful in dropsies, febrile affections, jaundice, scurvy, calculus, and several chronic skin diseases. During its exhibition the urine becomes at first neutral, and then alkaline, owing to the salt being converted into carbonate of potassium in the system.—Dose. As a diaphoretic and antiscorbutic, 15 to 20 gr.; as a diuretic, 20 to 60 gr.; as an aperient, 2 to 3 dr.; in each case dissolved in some bland liquid, or in the infusion of some mild vegetable bitter.

Potassium Antimoniates. The normal potassic antimoniate may be obtained by heating, in an earthen crucible, 1 part of metallic antimony with 4 parts of nitrate of potash. The mass so obtained is reduced to powder, and afterwards washed with warm water to remove the excess of potash and potassic nitrite. The residue must be boiled in water for an hour or two; the insoluble anhydrous antimoniate is thus converted into a soluble hydrated modification (K2Sb2O6,5H2O.) The insoluble residue now consists chiefly of acid antimoniate of potassium. The normal salts possess the property of readily dissolving the acid antimoniate, which is precipitated when such a solution is mixed with any neutral salt of one of the alkalies. The normal antimoniate does not crystallise, and has an alkaline reaction.

Acid antimoniate of potassium (K2Sb4O11.) may be procured by passing a stream of carbonic anhydride through a solution of the normal antimoniate.

Acid metantimoniate of potash, or hydro-potassic metantimoniate is prepared as follows:—Potassic antimoniate is first formed by deflagrating antimony with nitre, the residue being washed and boiled as described above, so as to bring the whole of the normal antimoniate into solution; the resulting liquid is filtered, and evaporated to a syrup consistence in a silver dish, fragments of caustic potash are then added, and the evaporation is continued until a drop of liquid placed upon a cold slip of glass begins to crystallise; it is then allowed to cool and the alkaline supernatant liquid is poured off the crystals, which are allowed to drain upon a porous tile. This salt is employed as a test for sodium.

Potassium, Arseniate of. KH2AsO4. Syn. Arseniate of potassa, Monopotassic arseniate, Potassium dihydric arseniate; Potassæ binarsenias, L. Prep. Take of arsenious acid (white arsenic) and nitrate of potassium, of each, in powder, 1 part; heat the mixture to dull redness in a glass flask, until it fuses and red vapours cease to be evolved; dissolve the residuum, when cold, in boiling distilled water, 50 parts; concentrate the solution by evaporation, and set it aside to crystallise.

Prop., &c. This salt forms large crystals, which are permanent in dry air, soluble in about 4⁄2 parts of water, and insoluble in alcohol. It is reputed tonic, alterative, and antiperiodic.—Dose, ⁄16 to ⁄8 gr. dissolved in sweetened water. It is also used to form a resist-paste in calico printing, and in the manufacture of cobalt blue.

Potassium, Borate of. K4B4O8. Syn. Potassæ boras, L. Prep. From dry carbonate of potassium and dry boracic acids, equal parts, reduced to powder, and heated to redness in a covered crucible; the sublimed mass, when cold, being dissolved in boiling water, and the filtered solution concentrated by evaporation, and then set aside to crystallise; or at once completely evaporated to dryness.—Dose, 1 to 6 gr.; in calculi, &c.

Potassium, Borotartrate of. Syn. Potassæ borotartras, Cremor tartari solubilis, L.; Crème de tartre soluble, Fr. Prep. (P. Cod.) Crystallised boracic acid, 1 part; bitartrate of potassium, 4 parts; water, 24 parts; dissolve, by the aid of heat, in a silver basin, and, constantly stirring, evaporate the resulting solution, either to dryness, and then powder it, or merely to a syrupy consistence, when it may be spread upon plates, and dried in scales, by the heat of a stove. It must afterwards be preserved from the air.

Prop., &c. A white, deliquescent powder, freely soluble in water. It has been used as a solvent for lithic calculi, and in gout, &c.—Dose, 15 to 30 gr. In doses of 2 to 3 dr. it is laxative, and is very popular as such on the Continent.

Potassium, Bromide of. KBr. Syn. Potassii bromidum (B. P.). Prep. Exactly as the iodide, which it resembles in its character, only being somewhat less soluble in water and more in alcohol. Employed in similar cases and given in similar doses to the iodide.

Potassium, Carbonate of. K2CO3. Syn. Carbonate of potassa, Subcarbonate of potassa, Salt of tartar; Potassæ carbonas (B. P., Ph. L., E., D.). Impure or crude carbonate of potassium is chiefly imported from America and Russia, and is obtained by lixiviating wood ashes, and evaporating the solution to dryness. The mass is then transferred into iron pots, and is kept in a state of fusion for several hours, until it becomes quiescent, when the heat is withdrawn, and the whole is left to cool. It is next broken up and packed in air-tight barrels, and in this state constitutes the ‘potashes’ or ‘potash’ of commerce. Another method is to transfer the black salts, or product of the first evaporation, from the kettles to a large oven or furnace, so constructed that the flame is made to play over the alkaline mass, which is kept constantly stirred by means of an iron rod. The ignition is continued until the impurities are burned out, and the mass changes from a blackish tint to a dirty or bluish white. The whole is next allowed to cool, and is then broken into fragments, and packed in casks as before. It now constitutes ‘pearlash.’

When pearlash is dissolved in cold distilled water, the solution depurated, filtered and crystallised, or simply evaporated to dryness, it forms ‘refined ashes,’ or carbonate of potash sufficiently pure for most pharmaceutical and technical purposes. The granulated carbonate of potash, salt of tartar, or prepared kali, of the shops, is simply refined ashes which, during the evaporation, and more especially towards the conclusion of the desiccation, has been assiduously stirred, so that it may form small white granulations, instead of adhering together to form an amorphous solid mass. In this state it constitutes the ordinary or carbonate of potassa of the Pharmacopœias. Ordinary potash or pearlash may be refined as follows:—Raw potash, 10 parts, is dissolved in cold water, 6 parts, and the solution is allowed to remain for 24 hours, in a cool place; it is then filtered, and somewhat concentrated by evaporation, crystallisation being prevented by continually stirring the mass until the whole is nearly cold; it is next decanted into a strainer, and the mother-liquor allowed to drip off; the residuum is evaporated to dryness at a gentle heat, and redissolved in an equal quantity of cold distilled water; the new solution, after filtration, is again evaporated to dryness. The product is quite free from potassium sulphate, and is nearly free from both potassium chloride and silicates.

Potassium, Pure Carbonate of. Carbonate of potassa (Potassæ carbonas purum—Ph. E. & D., and Ph. L., 1836).—(Ph. L., 1836.) From bicarbonate of potassium, in crystals, heated to redness in a crucible.

(Ph. E.) As the last. Or, more cheaply, by dissolving bitartrate of potassium in thirty parts of boiling water, separating and washing the crystals which form on cooling, heating them in a loosely covered crucible to redness as long as fumes are discharged, breaking down the mass, and roasting it in an oven for two hours, with occasional stirring; lixiviating the product with (cold) distilled water, filtering the solution thus obtained, evaporating it to dryness, granulating the salt towards the close by brisk agitation; and, lastly, heating the granular salt thus obtained nearly to redness.

(Ph. D.) Bitartrate of potassium, 2 lbs., is exposed to a red heat in an iron crucible, as before; the powdered calcined mass is boiled for 20 minutes in water, 1 quart, the solution filtered, and the filtrate washed with water, 1 pint, to which ammonium sesquicarbonate, ⁄2 oz., has been added; the mixed and filtered liquors are evaporated to dryness, and, a low red heat having been applied, the residuum is rapidly reduced to powder in a warm mortar, and at once enclosed in (dry and) well-stoppered bottles.

Prop. These are well known. It exhibits most of the properties of hydrate of potassium, but in a vastly less degree. It is very deliquescent, effervesces with acids, exhibits a marked alkaline reaction with test paper, is insoluble in alcohol, but dissolves in less than its own weight of water, its affinity for the last being so great that it takes it from alcoholic mixtures.

Pur., &c. Carbonate of potassium frequently contains an undue quantity of water, as well as silicic acid, sulphates, and chlorides. The water may be detected by the loss of weight the salt suffers when heated; the silica, by adding to it hydrochloric acid in excess, evaporating to dryness, and igniting the residuum, by which this contamination is rendered insoluble; the sulphates and chlorides may be detected by adding nitric acid in excess, and testing the liquid with nitrate of silver and chloride of barium. If the former produces a white precipitate, a chloride is present; and if the latter does the same, the contamination is a sulphate. Carbonate of potassium deliquesces in the air, and is almost entirely dissolved by water; in an open vessel it spontaneously liquefies. It changes the colour of turmeric brown. Supersaturated with nitric acid, neither carbonate of sodium nor chloride of barium throws down anything, and nitrate of silver very little. 100 gr. lose 16 gr. of water by a strong red heat; and the same weight loses 26·3 gr. of carbonate anhydride when placed in contact with dilute sulphuric acid.

Potassium, Bicarbonate of. KHCO3. Syn. Potassium hydrogen carbonate, Bicarbonate of potassa; Potassæ bicarbonas (B. P., Ph. L., E., & D.). Prep. 1. (Ph. L. 1836.) Carbonate of potassium, 6 lbs.; distilled water, 1 gall.; dissolve, and pass carbonic anhydride (from chalk and sulphuric acid diluted with water) through the solution to saturation; apply a gentle heat, so that whatever crystals have been formed may be dissolved, and set aside the solution that crystals may again form; lastly, the liquid being poured off, dry them.

2. (Ph. D.) Carbonic anhydride, obtained by the action of dilute hydrochloric acid on chalk (the latter contained in a perforated bottle immersed in a vessel containing the acid), is passed, by means of glass tubes connected by vulcanised india rubber, to the bottom of a bottle containing a solution of carbonate of potassium, 1 part, in water, 2⁄2 parts; as soon as the air is expelled from the apparatus the corks through which the tubes pass are rendered air-tight, and the process left to itself for a week; the crystals thus obtained are then shaken with twice their bulk of cold water, drained, and dried on bibulous paper, by simple exposure to the air. From the mother-liquor, filtered, and concentrated to one half, at a heat not exceeding 110° Fahr., more crystals may be obtained. The tube immersed in the solution of carbonate of potassium will have to be occasionally cleared of the crystals with which it is liable to become choked, else the process will be suspended.

3. (Ph. B.) The same.

4. (Apothecaries’ Hall, London.) Potassium carbonate, 100 lbs.; distilled water, 17 galls.; dissolve, and saturate the solution with carbonic anhydride, as in No. 1, when 35 to 40 lbs. of crystals of bicarbonate of potassium may be obtained; next dissolve carbonate of potassium, 50 lbs., in the mother-liquor, and add enough water to make the whole a second time equal to 17 galls.; the remaining part of the operation is then to be performed as before. This plan may be repeated again and again, for some time, provided the carbonate used is sufficiently pure.

5. (Ph. E.) Take of carbonate of potassium, 6 oz.; sesquicarbonate of ammonium, 3⁄2 oz.; triturate them together, and, when reduced to a very fine powder and perfectly mixed, make them into a stiff paste with a very little water; dry this, very carefully, at a heat not higher than 140° Fahr., until a fine powder, perfectly devoid of ammoniacal odour, be obtained, occasionally triturating the mass towards the end of the process.

6. (Commercial.) From carbonate of potassium, in powder, made into a paste with water, and exposed for some time on shallow trays, in a chamber filled with an atmosphere of carbonic anhydride, generated by the combustion of either coke or charcoal, and purified by being forced through a cistern of cold water; the resulting salt is next dissolved in the least possible quantity of water at the temperature of 120° Fahr., and the solution filtered and crystallised.

Prop. It is soluble in 4 times its weight of water at 60° Fahr.; is fixed in the air, but loses carbonic acid below the temperature of a carbonate at a red heat. It possesses the general alkaline properties of carbonate of potassium, but in an inferior degree, having only a slightly alkaline taste, and, when absolutely pure, not affecting the colour of turmeric.

Pur. In a solution of pure bicarbonate of potassium a solution of mercuric chloride merely causes an opalescence, or very slight white precipitate; if it contains carbonate, a brick-coloured precipitate is thrown down. From 100 gr. of the pure crystals of bicarbonate, 30·7 gr. of water and carbonic acid are expelled at a red heat. In other respects it may be tested like the carbonate.

Uses, &c. Bicarbonate of potassium is the most agreeable of all the salts of potassium, and is much used as an antacid or absorbent, and for making effervescing saline draughts. It has also been successfully employed in rheumatism, scurvy, gout, dyspepsia, and various other diseases in which the use of potassium is indicated. The dose is from 10 gr. to ⁄2 dr.

20 gr. bicarbonate, in crystals,

are equivalent to

14 gr. of crystallised nitric acid,

15 gr. of crystallised tartaric acid, and

⁄2 oz. of lemon juice.

Potassium, Chlorate of. KClO3. Syn. Chlorate of potash; Potassæ chloras (B. P., Ph. L. & D.), L. Prep. 1. Chlorine gas is conducted by a wide tube into a moderately strong and warm solution of hydrate or carbonate of potassium, until the absorption of the gas ceases and the alkali is completely neutralised; the liquid is then kept at the boiling temperature for a few minutes, after which it is gently evaporated (if necessary) until a pellicle forms on the surface, and is next set aside, so as to cool very slowly; the crystals, thus obtained, are drained and carefully washed on a filter, with ice-cold water, and are purified by re-solution and re-crystallisation. The product is chlorate of potassium. The mother-liquor, which contains much chloride of potassium mixed with some chlorate, is either evaporated for more crystals (which are, however, less pure than the first crop) or is preserved for a future operation.

Obs. The product of the above process is small, varying from 10 to 45% of the weight of the potassium consumed in it, according to the skill with which it is conducted; this apparent loss of potassium arises from a large portion of it being converted into chloride, a salt of comparatively little value. The following processes have been devised principally with the view of preventing this waste, or of employing a cheaper salt of potassium than the carbonate:—

2. (Ph. B.) Mix slaked lime, 53 oz., with carbonate of potash, 20 oz., and triturate them with a few ounces of distilled water, so as to make the mixture slightly moist. Place oxide of manganese, 80 oz., in a large retort or flask, and having poured upon it hydrochloric acid, 24 pints, diluted with 6 pints of water, apply a gentle sand heat, and conduct the chlorine as it comes over, first through a bottle containing 6 oz. of water, and then into a large carboy containing the mixture of carbonate of potash and slaked lime. When the whole of the chlorine has come over remove the contents of the carboy and boil them for 20 minutes with 7 pints of distilled water; filter and evaporate till a film forms on the surface, and set aside to cool and crystallise.

The crystals thus obtained are to be purified by dissolving them in 3 times their weight of boiling distilled water, and again allowing the solution to crystallise.—Dose, 10 gr. to 30 gr.

3. A solution of chloride of lime is precipitated with a solution of carbonate of potassium, and the liquid, after filtration, saturated with chlorine gas; it is then evaporated and crystallised as before. Dr Ure has suggested the substitution of sulphate of potassium for the carbonate, by which the process would be rendered very inexpensive.

4. Carbonate of potassium, 69 parts of the dry or 82 parts of the granulated, hydrate of calcium, 37 parts (dry fresh slaked lime), both in powder, are mixed together, and exposed to the action of chlorine gas, to saturation (the gas is absorbed with great rapidity, the temperature rises above 212° Fahr., and water is freely evolved); the heat, with free exposure, is then maintained at 212° for a few minutes (to remove some trace of ‘hypochlorite’), the residuum, consisting of chlorate of potassium and chloride of calcium, is treated with hot water, and the chlorate of potassium crystallised out of the resulting solution, as before. This process, which is an excellent one (the loss of potassium being for the most part avoided), has been modified and improved by various authorities, as will be seen below.

5. A solution of chloride of lime (18° to 20° Baumé) is heated in a leaden or cast-iron vessel, and sufficient of a salt of potassium added to raise the density of the liquid 3 or 4 hydrometer degrees; the solution is then quickly, but carefully, concentrated until the gravity rises to 30° or 31° Baumé, when it is set aside to crystallise. A good and economical process.

6. Chloride of potassium, 76 parts, and fresh calcium hydrate, 222 parts, are reduced to a thin paste with water, q. s., and a stream of chlorine gas passed through the mixture, to saturation; chloride of calcium and chlorate of potassium are formed; the last is then removed by solution in boiling water, and is crystallised as before. This process, which has received the approval and recommendation of Liebig, has long been practised in Germany, and was originally introduced to this country by Dr Wagenmann. The product is very large, and of excellent quality.

Prop. White, inodorous, four-or six-sided pearly scales, soluble in about 20 parts of cold and 2⁄2 parts of boiling water; in taste it resembles nitre, but is somewhat more austere; at about 450° Fahr. it undergoes the igneous fusion, and on increasing the heat almost to redness effervescence ensues, and fully 39% of pure oxygen gas is given off, whilst the salt becomes changed into chloride of potassium. When mixed with inflammable substances and triturated, heated, or subjected to a smart blow or strong pressure, or moistened with a strong acid, it explodes with great violence.

Pur., Tests, &c. The usual impurity of this salt is chloride of potassium, arising from careless or imperfect manipulation. When this is present, a solution of nitrate of silver gives a curdy white precipitate, soluble in ammonia; whereas a solution of the pure chlorate remains clear.

Uses. Chlorate of potassium is principally used in the manufacture of lucifer matches, fireworks, oxygen gas, &c., and as an oxidising agent in calico printing. It was formerly used to fill percussion caps, but was abandoned for fulminating mercury, on account of its disposition to rust the nipples of the guns. As a medicine it is stimulant and diuretic. It has been given in dropsy, syphilis, scurvy, cholera, typhus, and other depressing affections. It gives a fine artificial colour to the blood. (Stevens.)—Dose, 5 to 15 gr., in solution, twice or thrice a day.

Concluding Remarks.—Formerly, chlorate of potassium was a salt which was made only on the small scale, and chiefly used in experimental chemistry; now it is in considerable demand, and forms an important article of chemical manufacture. The latter has hence, of late years, received considerable attention and improvement in the leading laboratories of Europe. The chlorate requires to be handled with great care. It should never be kept in admixture with any inflammable substance, more especially with sulphur, phosphorus, or the sulphides, as these compounds are exploded by the most trivial causes, and, not unfrequently, explode spontaneously.

Potassium, Chloride of. KCl. Syn. Chloride of potassa. Prep. The chloride of potassium of commerce is usually a secondary product in the manufacture of chlorate of potassium and other substances. The mother-liquor of the former is evaporated to dryness and heated to dull redness, the calcined mass is then dissolved in water, the solution purified by defecation and evaporated down for crystals.

It can also be well prepared by neutralising boiling solution of carbonate of potassium by dilute hydrochloric acid, evaporating down, and crystallising.

Prop., &c. It closely resembles culinary salt in appearance; is anhydrous; dissolves in about 4 parts of cold and 2 of boiling water; has a slightly bitter, saline taste; fuses at a red heat; and is volatilised at a very high temperature. As a medicine it is diuretic and aperient. It was formerly in high repute as a resolvent and antiscorbutic, and, particularly, as a remedy for intermittents. It is now seldom used.—Dose, 10 gr. to ⁄2 dr., or more.

Potassium, Chromate of. K2CrO4. Syn. Chromate of potassa, Neutral chromate of p., Monochromate of p., Yellow C. of p., Salt of chrome; Potassæ chromas, P. c. flava, L. This salt is only prepared on the large scale. Its source is ‘CHROME ORE,’ a natural octahedral chromate of iron, found in various parts of Europe and America. For medicinal purposes the commercial chromate is purified by solution in hot water, filtration, and recrystallisation.

Prep. 1. The ore, previously assayed to determine its richness, and freed as much as possible from its gangue, is ground to powder in a mill, and mixed with a quantity of coarsely powdered nitre rather less than that of the oxide of chromium which it contains; this mixture is exposed, for several hours, to a powerful heat on the hearth of a reverberatory furnace, during which time it is frequently stirred up with iron rods; the calcined mass is next raked out and lixiviated with hot water, and the resulting yellow-coloured solution evaporated briskly over a naked fire, or by the heat of high-pressure steam; chromate of potassium falls, under the form of a granular yellow salt, which is removed from time to time with a ladle, and thrown into a wooden vessel, furnished with a bottom full of holes (draining box), where it is left to drain and dry. In this state it forms the chromate of potassium of commerce. By a second solution and recrystallisation, it may be obtained in large and regular crystals. The next process has for its object the employment of a cheaper salt of potassa than the nitrate.

2. (Swindell & Co. Patent dated Nov., 1850.) A mixture of pulverised chrome ore and chloride of potassium is exposed to a full red heat, on the hearth of a reverberatory furnace, with occasional stirring for some time, when steam at a very elevated temperature is made to act on it until the conversion is complete, known by assaying a portion of the mass; the chromate is then dissolved out of the residuum, as before. Common salt or hydrate of calcium may be substituted for chloride of potassium, when the chromates of sodium or calcium are respectively produced.

3. On the small scale this salt may be prepared from the bichromate by neutralising it with hydrate of potassium.

Prop. Yellow; tastes cool, bitter, and disagreeable; soluble in 2 parts of water at 60° Fahr.; the crystals are efflorescent.

Pur. The salt of commerce is frequently contaminated with large quantities of sulphate or chlorate of potassium. To detect these, M. Zueber adds tartaric acid, dissolved in 50 parts of water, to a like solution of the sample. As soon as the decomposition is complete, and the colour verges towards the green, the supernatant liquor should afford no precipitate with solutions of the nitrates of silver and barium, whence the absence of chlorides and sulphates may be respectively inferred. The proportions are, 8 parts of tartaric acid to 1 part of the chromate. If saltpetre is the adulterating ingredient, the sample deflagrates when thrown upon burning coals.

Assay. 1. A solution of 50 gr. of the salt is treated with a solution of nitrate of barium, the precipitate digested in nitric acid, and the insoluble portion (sulphate of barium) washed, dried, and weighed. 117 gr. of this substance are equivalent to 89 gr. of sulphate of potassium.

2. The nitric solution, with the washings (see above), is treated with a solution of nitrate of silver, and the precipitate of chloride carefully collected, washed, dried, ignited, and weighed. 144 gr. of chloride of silver represent 76 gr. of chloride of potassium.

3. The nitric solution, with the washing (see above), after having any remaining barium thrown down by adding dilute sulphuric acid, in slight excess, is treated with ammonia, and the resulting precipitate of chromic oxide collected on a filter, washed, dried, carefully ignited in a silver, platinum, or porcelain crucible, and weighed. 40 gr. of this oxide represent 100 gr. of pure chromate of potassium. Any deficiency consists of impurities or adulterants.

Uses. Chromate of potassium is used in dyeing, bleaching, the manufacture of chromic acid, bichromate of potassium, &c. It is the common source of nearly all the other compounds of chromium. It is reputed alterative in doses of ⁄12 to ⁄2 gr.; and is emetic in doses of 1 to 4 gr. A solution in 8 parts of water is occasionally used to destroy fungus; 1 in 30 to 40 parts of water is also used as an antiseptic and desiccant.

Concluding Remarks.—The first process is undoubtedly the best, when expense is not an object. To reduce this, a mixture of ‘potash’ or ‘pearlash,’ with about ⁄2 of its weight of nitre, or 1-5th part of its weight of peroxide of manganese, may be substituted without much inconvenience. The assay of the chrome ore, alluded to above, may be made by reducing 100 gr. of it to powder, mixing it with twice its weight of powdered nitre, and a little hydrate of calcium, and subjecting the mixture to a strong red heat for 3 or 4 hours; the calcined mass may then be exhausted with boiling water, and the resulting solution, after precipitation with dilute sulphuric acid, in slight excess, and filtration, may be treated with rectified spirit, when its chromium may be thrown down by the addition of ammonia. (See above.) In the conversion of chrome ore into chromate of potassium care should, in all cases, be taken that the proportion of nitre or alkali should be slightly less than what is absolutely required to saturate the ore, as the production of a neutral salt is thereby ensured; for should not the whole of the chromate be decomposed by the first calcination, it may easily be roasted a second time with fresh alkali, should the remaining quantity he thought worth the trouble. The nature of the furnace to be employed in the conversion is not of any great importance, so long as carbonaceous matters from the fire are entirely excluded, and the required temperature is attainable.

Potassium, Bichromate of. K2Cr2O7, or K2CrO4,CrO3. Syn. Bichromate of potassa, Red chromate of potash, Acid c. of p.; Potassæ bichromas, L. Prep. 1. To a concentrated solution of yellow chromate of potassium, sulphuric acid, or, better, acetic acid, is added in quantity equal to one half that required for the entire decomposition of the salt; the liquid is then concentrated by evaporation and slowly cooled, so that crystals may form.

2. (Jacquelain.) Chrome ore, finely ground and sifted, is mixed with chalk; the mixture is spread on a thin layer on the hearth of a reverberatory furnace, and heated to bright redness, with repeated stirring, for 9 or 10 hours. The yellowish-green product consists essentially of neutral chromate of calcium, mixed with ferric oxide. It is ground and stirred up with hot water, and sulphuric acid is added till a slight acid reaction becomes apparent, a sign that the neutral chromate has been converted into bichromate. Chalk is now stirred in to precipitate the ferric sulphate, and after a while the clear solution is run off into another vessel, where it is treated with carbonate of potassium, which precipitates the lime and leaves bichromate of potassium in solution. The solution is then evaporated to the crystallising point. This process, when carried out on a large scale, is very economical.

Prop., &c. It forms very beautiful square tables, or flat four-sided prismatic crystals; permanent in the air; soluble in 10 parts of water at 60°, and in less than 3 parts at 212° Fahr.; it has a metallic, bitter taste, and is poisonous. It is chiefly used in dyeing and bleaching, and as a source of chromic acid. The tests, &c., are the same as for the yellow chromate.

Potassium, Citrate of. K3C6H5O7. Syn. Potassæ citras, L. Prep. From a solution of citric acid neutralised with carbonate of potassium, evaporated, and granulated, or crystallised; very deliquescent. Or, extemporaneously, in the form of solution, by adding carbonate or bicarbonate of potassium to lemon juice, as in the common effervescing draught. (Ph. B.) The same.

Potassium, Cyanate of. KCyO, or KCNO. Prep. 1. By roasting, at a red heat, dry ferrocyanide of potassium, in fine powder, upon an iron plate, constantly stirring it until it becomes fused into one mass, which must be reduced to fine powder and digested in boiling alcohol, from which crystals of the cyanate will be deposited as the solution cools.

2. (Liebig.) A mixture of ferrocyanide of potassium, with half its weight of peroxide of manganese, may also be used to produce this salt, as the last; the compound should be kindled by a red-hot body, and allowed to smoulder away, after which it may be treated with alcohol, as before.

3. A mixture of ferrocyanide of potassium and litharge is heated as before, and dissolved out by alcohol, and crystallised.

Prop. Crystallisable colourless or white salt, readily soluble in alcohol and water, but readily decomposed when moist into bicarbonate of potassium and ammonia, or in solution into the carbonate of potassium and ammonium.

This salt is poisonous. The cyanates of silver, lead, and many other metals may be made by adding a solution of cyanate of potassium to another of a neutral salt of the base.

Potassium, Cyanide of. KCN, or KCy. Syn. Cyanide of potash, Cyanuret of potassium; Potassii cyanidum, P. cyanuretum, L.

Prep. 1. (Medicinal cyanide of potassium.)—a. A solution of pure hydrate of potassium, 2 parts, in highly rectified spirit, 7 parts, is placed in a receiver furnished with a safety tube, and surrounded with bruised ice; the beak of a tubulated retort, containing ferrocyanide of potassium, in powder, 4 parts, is then adapted to it in such a manner that any gas or vapour evolved in the retort must traverse the solution in the receiver; the arrangement being complete, sulphuric acid, 3 parts, diluted with an equal weight of water, and allowed to cool, is cautiously poured into the retort, and the distillation conducted very slowly, a very gentle heat only being applied, as circumstances may direct; as soon as the force of ebullition in the retort has subsided, the distillation is complete, and the connection between the retort and receiver is broken; the contents of the receiver, now transformed into a mixture of a crystalline precipitate of cyanide of potassium, and an alcoholic solution of undecomposed hydrate of potassium, is carefully thrown on a filter, and the precipitate, after the mother-liquor has drained off, very cautiously washed with ice-cold and highly rectified spirit, and then drained, pressed, and dried on the same filter. The product is chemically pure, and equal to fully 10% of the ferrocyanide employed. This is a modification of what is commonly known as ‘Wigger’s process.’

b. Expose well-dried and powdered ferrocyanide of potassium to a moderate red heat, in a close vessel; when cold, powder the fused mass, place it in a funnel, moisten it with a little alcohol, and wash it with cold water; evaporate the solution thus formed to dryness, expose it to a dull red heat in a porcelain dish, cool, powder, and digest it in boiling rectified spirit; as the spirit cools, crystals of cyanide of potassium, nearly pure, will be deposited. The alcohol employed in both this and the preceding process may be recovered by distillation from calcined sulphate of iron.

2. (Crude or commercial cyanide—Liebig.) Commercial ferrocyanide of potassium, 8 parts, rendered anhydrous by gently heating it on an iron plate, is intimately mixed with dry carbonate of potassium, 3 parts; this mixture is thrown into a red-hot earthen crucible, and kept in a state of fusion, with occasional stirring, until gas ceases to be evolved, and the fluid portion of the mass becomes colourless; the crucible is then left at rest for a few minutes, to allow its contents to settle, after which the clear portion is poured from the heavy black sediment at the bottom upon a clean marble slab, and the mass, whilst yet warm, broken up, and placed in well-closed bottles.

Obs. A cheap and excellent process. The product is said to contain about 1-8th part of cyanate of potassium, and, though not sufficiently pure for employment in medicine as potassium cyanide, is admirably adapted for the various technical applications of this substance, as in electro-plating, electro-gilding, photography, &c. It may also be advantageously substituted for the ferrocyanide in the preparation of hydrocyanic acid by the distillation of that substance along with dilute sulphuric acid.

Prop., &c. When pure, this salt is colourless and odourless; it forms cubic or octahedral crystals, which are anhydrous; it is freely soluble in water and in boiling alcohol, but most of it separates from the latter as the solution cools; it is fusible; and undergoes no change, even at a full red heat, in close vessels; it exhibits an alkaline reaction; when exposed to the atmosphere, it absorbs moisture, and acquires the smell of hydrocyanic acid. If it effervesces with acids, it contains carbonate of potassium, and if it be yellow it contains iron. It is employed in chemical analysis, and for the preparation of hydrocyanic acid; cyanide of sodium may be made in the same way. The dose is ⁄12 to ⁄4 gr., in solution; in the usual cases in which the administration of hydrocyanic acid is indicated.—Antidotes. The same as for hydrocyanic acid.

Potassium, Ferricyanide of. K3FeCy6, or K3,FeC6N6. Syn. Ferridcyanide of potassium, Ferricyanuret of p., Red prussiate of potash; Potassii ferricyanidum, P. prussias rubrum, L. This important and beautiful salt was discovered by L. Gmelin. At first it was merely regarded as a chemical curiosity, but it is now extensively employed in dyeing, calico printing, assaying, &c.

Prep. 1. Chlorine gas, prepared in the ordinary manner, is slowly passed into a cold solution of ferrocyanide of potassium, 1 part, in water, 10 parts, with constant agitation, until the liquid appears of a deep reddish-green colour, or of a fine red colour by transmitted light, and ceases to give a blue precipitate, or even a blue tinge, to a solution of ferric chloride, an excess of chlorine being carefully avoided; the liquor is next evaporated by the heat of steam or boiling water, until a pellicle forms upon the surface, when it is filtered, and set aside to cool; the crystals are afterwards purified by re-solution and re-crystallisation.—Another method is simply to evaporate the original solution to dryness, by a steam heat, with agitation, then to re-dissolve the residuum in the least possible quantity of boiling water, and, after defecation or filtration, to allow the new solution to cool very slowly, that crystals may form.

2. (Extemporaneous.) Add nitric acid, very gradually, to a cold solution of ferrocyanide of potassium, with constant agitation, until a drop of the mixture ceases to impart a blue colour to a solution of ferric chloride, carefully avoiding excess of acid. It may be at once used in solution, or evaporated, &c., as before.

Prop, &c. Magnificent regular prismatic or, sometimes, tubular crystals, of a rich ruby-red tint; permanent in the air; combustible; decomposed by a high temperature; soluble in 4 parts of cold water; insoluble in alcohol. Colours ferric salts a pale brown, gives with ferrous salts a deep blue, and precipitates bismuth salts pale yellow; cadmium and mercuric salts, yellow; zinc salts, deep yellow; mercurous, cupric, molybdenic, silver, and uranic salts, reddish brown; cobalt salts, dark brown; manganous salts, brown; cupric salts, greenish; and nickelous salts, olive brown.

Potassium, Ethylate. (C2H5KO.) Löweg and Weidmann obtained this compound by heating together acetate of ethyl and potassium. Dr B. W. Richardson, some few years ago, recommended the employment of the alkaline ethylates as caustics, and they are now frequently used as such in surgery. When first applied to the body the ethylates produce no action, but as they absorb water from the tissues they are decomposed, the potassium or sodium is oxidised, yielding caustic potash or soda in the fresh condition, while alcohol is reformed from the recombination of hydrogen derived from the water. Dr Richardson believes the ethylates of potassium and sodium will be found the most effective and manageable of all caustics, and that in cases of cancer, when it is important to destroy structure without resorting to the knife, and in the removal of nævus and other simple growths, they will be of essential service. The ethylates dissolve in alcohol of different strengths; the solution may either be applied with a glass brush or injected by the needle, and a slow or quick effect can be insured according to the wish of the operator. The ethylate of potassium is the more powerful agent.

Potassium, Ferrocyanide of. K4,FeCy6, or K4,FeC6N6. Syn. Ferrocyanuret of potassium, Prussiate of potash, Yellow p. of p.; Potassæ prussia flava (B. P.), Potassii ferrocyanidum (Ph. L., E., & D.), L. This valuable salt, the well-known ‘prussiate of potash’ of commerce, was discovered by the illustrious Scheele about the middle of the 18th century. It is now only manufactured on the large scale.

Prep. Good ‘potash’ or ‘pearlash,’ 2 parts, and dried blood, horns, hoofs, woollen rags, or other refuse animal matter, 5 or 6 parts, are reduced to coarse powder, and mixed with some coarse iron borings; the mixture is then injected into egg-shaped cast-iron pots in a state of moderate ignition; the mass is frequently stirred with an iron spatula, so as to prevent it running together, and the calcination is continued until fetid vapours cease to be evolved, and flame is no longer seen on stirring the mixture, care being taken to exclude the air from the vessels as much as possible; during the latter part of the process the pots are kept constantly covered, and the ignited mass stirred less frequently; the hot pasty mass is then removed with an iron ladle, and excluded from the air until cold; it is next exhausted by edulcoration with boiling water, and the resulting solution, after defecation or filtration, is concentrated by evaporation, so that crystals may form as the liquid cools; these are redissolved in hot water, and the solution allowed to cool very slowly, when large and beautiful yellow crystals of ferrocyanide of potassium are deposited.—Product. 1 ton of dried blood or woollen refuse, with 3 cwt. of pearlash, yields from 2 to 2⁄2 cwt. of commercial ferrocyanide. The mother-liquor contains sulphate of potassium.

Prop. It forms large and very beautiful yellow crystals, which are permanent in the air, and very tough and difficult to powder; it is soluble in 4 parts of cold and 2 parts of boiling water; has a mild saline taste; at a gentle heat loses water; at a higher temperature, in closed vessels, it is for the most part converted into cyanide of potassium, and, when exposed to the air, into cyanate of potassium. Precipitates solutions of antimonous, bismuth, mercurous, and zinc salts, white; cadmium salts, of a pale yellow; cuprous salts, white, turning red; ferrous salts, white, turning blue; lead salts, white; manganous salts, white, turned red; mercuric salts, white, turning bluish; nickelous salts, white, turning green; silver salts, white; stannous salts, white; cobalt salts, green; cupric salts, chocolate red; ferric salts, dark blue; palladous salts, green; stannic salts, yellow; uranic salts, reddish brown; and zinc salts, white.

Uses, &c. Ferrocyanide of potassium is chiefly used in dyeing and calico printing, in the manufacture of Prussian blue, in electro-plating, and, in chemistry, as a test, and a source of hydrocyanic acid. As a medicine it is said to be sedative and astringent, and in large doses purgative, but appears to possess little action.—Dose, 10 gr. to ⁄2 dr., dissolved in water; in hooping-cough, chronic bronchitis, night-sweats, leucorrhœa, &c. D’Arcet swallowed a solution containing ⁄2 oz. of this salt without experiencing any injurious effects.

Potassium, Hydrate of. KHO. Syn. Potassa hydrate, Hydrate of potassa, Potassa, Caustic p., Hydrated oxide of potassium; Potassa caustica (B. P.), Potassa (Ph. E.), P. caustica (Ph. D.), P. hydras (Ph. L.), P. fusa. Prep. 1. (Ph. L.) Liquor of potassa, 1 gall.; evaporate the water in a clean iron vessel over the fire until the ebullition being finished, the residuum of potassium hydrate liquefies; pour this into proper moulds.

2. (Ph. E. & D.) As the last, but pouring the fused hydrate upon a bright and clean iron plate (silver or iron dish—Ph. D.); as soon as it solidifies, break it quickly (into fragments), and put it into stoppered glass (green-glass—Ph. D.) bottles.

3. (Pure.) The hydrate, obtained as above, is dissolved in alcohol or rectified spirit, and, after repose for a few days in a closely stopped green-glass or silver vessel, the solution is decanted, and cautiously evaporated in a deep silver basin, out of contact with the air.

4. (Pure.) M. Polacci states that he procures very pure hydrate of potash in a few minutes by the following process. He heats together in an iron vessel to a red heat a mixture consisting of 1 part of nitrate of potash well triturated with 2 or 3 parts of iron filings. The mass becomes red in a few minutes, and, after cooling, it is treated with water, left to settle, and then decanted. A more or less concentrated solution may thus be obtained, or it may be evaporated to produce the solid potash.

Prop., &c. When perfectly pure it is white, solid, very soluble in water and in alcohol; very deliquescent; intensely acrid and corrosive; and exhibiting the usual signs of alkalinity in the highest degree. That of the shops has usually a greyish or bluish colour.

Potassium, I′odate of. KIO3. Syn. Potassæ iodas. L. Prep. Neutralise a hot solution of hydrate of potassium with iodine, evaporate to dryness by a gentle heat, powder the residuum, and digest it in alcohol, to remove iodide of potassium, dissolve the insoluble portion in hot water, and crystallise.

Obs. Iodate of potassium is resolved at a red heat into oxygen gas and iodide of potassium. It has been recommended in bronchocele.—Dose, 1 to 5 gr.

Potassium, Iodide of. KI. Syn. Potassii iodidum (B. P., Ph. L., E., and D.).

1. (Ph. L. 1836.) Take of iron filings, 2 oz.; distilled water, 2 quarts; iodine, 6 oz,; mix them, and heat the solution until it turns green, and then add of carbonate of potassium, 4 oz., dissolved in water, 1 quart; filter, wash the residuum on the filter with water, evaporate the mixed filtered liquors and crystallise.—Product, 1 oz. of iodine yields 1 oz. 45 gr. of iodide.

The formulæ of the Ph. D. and Ph. E. are very similar.

2. Add iodine to a hot solution of pure hydrate of potassium until the alkali is perfectly neutralised, carefully avoiding excess; evaporate the liquid to dryness, and expose the dry mass to a gentle red heat in a platinum or iron crucible; afterwards dissolve out the salt, gently evaporate, and crystallise. An excellent process, yielding a large product, but, if the ignition be not carefully managed, it is apt to contain a little undecomposed iodate. To obviate this, Mr Scanlan proposes the addition of a little powdered charcoal to the mass before ignition—a plan adopted in the Ph. U. S.

3. Iodine is treated with a small proportion of phosphorus in water, and is thus converted into ‘hydriodic acid,’ hydrate of calcium is then added, and the ‘iodide of calcium’ formed is first fused, and then decomposed by sulphate of potassium into ‘sulphate of calcium,’ which is precipitated, and ‘iodide of potassium,’ which remains in solution, and may be crystallised, as in the other processes. This is a modification of a method devised by Liebig.

4. (Ph. B.) Put solution of potash, 1 gall., into a glass or porcelain vessel, and add iodine 29 oz., or q. s., in small quantities at a time, with constant agitation, until the solution acquires a permanent brown tint. Evaporate the whole to dryness in a porcelain dish, pulverise the residue, and mix this intimately with wood charcoal in fine powder, 3 oz. Throw the mixture, in small quantities at a time, into a red-hot crucible, and when the whole has been brought to a state of fusion, remove the crucible from the fire and pour out its contents. When the fused mass has cooled, dissolve it in 2 pints of boiling distilled water, filter through paper, washing the filter with a little distilled boiling water; unite the liquids, and evaporate till a film forms on the surface. Set aside to cool and crystallise. Drain crystals and dry quickly with a gentle heat; more crystals may be obtained by evaporating the mother liquor, and cooling. The salt should be kept in a stoppered bottle.

Prop. It crystallises in cubes, which in the pure salt are extremely white, though frequently opaque; these are anhydrous; fuse when heated, without decomposition; dissolve in less than an equal weight of water, at 60° Fahr., and very freely in alcohol; and do not deliquesce in moderately dry air unless they contain undecomposed hydrate of potassium. Its solution dissolves the iodine freely, and also, less readily, several of the insoluble metallic iodides and oxides.

Pur. It is entirely soluble in both water and alcohol. Its aqueous solution alters the colour of turmeric either not at all or but very slightly, nor does it affect litmus paper, or effervesce with acids. Nitric acid and starch being added together, it becomes blue. It is not coloured by the addition of tartaric acid with starch. No precipitate occurs on adding either a solution of hydrate of calcium or of chloride of barium. 100 gr., dissolved in water, by the addition of nitrate of silver, yield a precipitate of 141 gr. of iodide of silver.

Assay. The iodide of commerce frequently contains fully one half its weight of either chloride or carbonate of potassium, or both of them, with variable quantities of iodate of potassium, a much less valuable salt. The presence of these substances is readily detected by the above tests. As the first of these is only very slightly soluble in cold alcohol, and the others insoluble in that liquid, a ready method of determining the richness of a sample in pure iodide, sufficiently accurate for ordinary purposes, is as follows:—Reduce 50 gr. of the sample to fine powder, introduce this into a test tube with 6 fl. dr. of alcohol, agitate the mixture violently for one minute, and throw the whole on a weighed filter set in a covered funnel, observing to wash what remains on the filter with another fl. dr. of alcohol. The filtrate, evaporated to dryness, gives the quantity of pure iodide, and the filter, dried by the heat of boiling water, that of the impurities present in the sample examined, provided it contained no hydrate of potassium. The quantity of alkali, whether hydrate or carbonate, may be found by the common method of ‘alkalimetry.’

Uses, &c. Chiefly in photography, medicine, and pharmacy.—Dose, 1 to 10 gr., twice or thrice daily, made into pills, or, better, in solution, either alone or combined with iodine; in bronchocele, scrofula, chronic rheumatism, dropsy, syphilis, glandular indurations, and various other glandular diseases. Also externally, made into a lotion or ointment.

Potassium, Nitrate of. KNO3. Syn. Nitrate of potash, Nitre, Saltpeter; Potassæ nitras (B. P., Ph. L., E.,& D.), Nitrum†, Sal nitri†, Sal petræ†, Kali nitratum†, L. This salt is produced naturally in the soil by the action of the atmosphere, and crystallises upon its surface, in various parts of the world, especially in the East Indies. On the Continent it has long been produced artificially, by exposing a mixture of calcareous soil and animal matter to the atmosphere, when calcium nitrate is slowly formed, and is extracted by lixiviation. The liquid is then decomposed by the addition of wood ashes, or carbonate of potassium, by which carbonate of calcium is precipitated, and nitrate of potassium remains in solution. The places where these operations are performed are called ‘nitriaries,’ or ‘nitrières artificielles.’ The British market is wholly supplied from India. The salt of the first crystallisation, by either process, is called ‘crude nitre’ or ‘rough saltpetre.’ This is purified by solution in boiling water, skimming, and, after a short time allowed for defecation, straining (while still hot) into wooden crystallising vessels. The crystals thus obtained are called ‘single refined nitre,’ and when the process is repeated ‘double refined nitre.’

1. (Potassæ nitras purum—Ph. D.) Commercial nitre, 4 lbs.; boiling distilled water, 1 quart; dissolve, withdraw the heat, and stir the solution constantly as it cools; the minute crystals, thus obtained, are to be drained, and washed, in a glass or earthenware percolator, with cold distilled water, until that which trickles through ceases to give a precipitate with a solution of nitrate of silver, the contents of the percolator are then to be withdrawn, and dried in an oven.

Prop. White, pellucid, six-sided prisms; permanent in the air; soluble in 7 parts of water at 60° and in 1 part at 212° Fahr.; insoluble in alcohol; its taste is cool, saline, and slightly bitter and pungent; at about 560° it fuses to an oily-looking mass, which concretes on cooling, forming ‘sal prunella,’ at a red heat it gives out oxygen, and, afterwards, nitrous fumes; sp. gr. 1·925 to 1·975.

Pur. Commercial nitre generally contains chlorides, sulphates, or calcareous salts. The first may be detected by its solution giving a cloudy white precipitate with nitrate of silver. The second by chlorides of barium or calcium giving a white precipitate, and the third by oxalate of ammonium giving a white precipitate.

Assay. Of the numerous methods prescribed for this purpose, few are sufficiently simple for mere practical men. The proportion of chlorides, sulphates, and calcareous salts may be determined as above; and the general richness of the sample by the method of Gay-Lussac, modified as follows:—100 gr. of the sample (fairly chosen) are triturated with 50 gr. of lampblack and 400 gr. of common salt, and the mixture placed in an iron ladle, and ignited or fused therein, due care being taken to prevent loss; the residuum is exhausted with hot water, and the solution thus obtained tested by the usual methods of alkalimetry for carbonate of potassium. The quantity of carbonate found, multiplied by 2·125 or 2⁄8, gives the per-centage richness of the sample in nitrate.

Uses, &c. Nitre is chiefly employed in the manufacture of gunpowder, fireworks, and nitric acid. It is also used in medicine as a sedative, refrigerant, and diaphoretic, and as a cooling diuretic. It has been recommended in active hæmorrhages (especially spitting of blood), in various febrile affections, in scurvy, and in herpetic eruptions; and it has been highly extolled by Dr Basham as a remedy in acute rheumatism.—Dose, 5 to 15 gr., every 2 hours. A small piece, dissolved slowly in the mouth, frequently stops a sore throat at the commencement. In large doses it is poisonous. The best treatment is a powerful emetic, followed by opiates.

Potassium, Nitrite of. KNO2. Syn. Nitrite of potassa; Potassæ nitris, L. Prep. 1. By heating nitre to redness, dissolving the fused mass in a little water, and adding twice the volume of the solution in alcohol; after a few hours the upper stratum of liquid is decanted, and the lower one, separated from the crystals, evaporated to dryness.

2. (Corenwinder.) Nitric acid, 10 parts, are poured on starch, 1 part, and the evolved gas passed through a solution of hydrate of potassium of the sp. gr. 1·380, to saturation; the liquid is then either neutralised with a little hydrate of potassium (if necessary), and kept in the liquid form, or at once evaporated. Fused pinkish mass, or clear colourless soluble crystals, used in chemistry as a reagent, and deoxidiser.

Potassium, Oxalate of. K2C2O4. Syn. Neutral oxalate of potassa; Potassæ oxalas, L. Prep. Neutralise a solution of oxalic acid, or the acid oxalates, with carbonate of potassium, evaporate, and crystallise. Transparent colourless rhombic prisms, soluble in 3 parts of water, and of the formula K2C2O4,Aq.

Potassium, Hydrogen Oxalate of. KHC2O4. Syn. Potassium binoxalate, Salt of sorrel, Essential salt of lemons; Potassæ binoxalas, L. Prep. By saturating a solution of oxalic acid, 1 part, with carbonate of potassium, adding to the mixture a similar solution of 1 part of oxalic acid, unneutralised, and evaporating for crystals. It may also be obtained from the expressed juice of wood or sheep’s sorrel, by clarifying it with eggs or milk, and evaporating, &c., as before. Colourless rhombic crystals of the formula KHC2O4,Aq., soluble in 40 parts of cold and 6 parts of boiling water, yielding a very sour solution.

Potassium, Trihydrogen Oxalate of. KH3(C2O4), or KHC2O4, H2C2O4. Syn. Potassium quadroxalate, Potassium acid oxalate. Prep. By neutralising 1 part of oxalic acid with carbonate of potassium, adding to the solution 3 parts more of oxalic acid, evaporating and crystallising. Resembles the last; has the formula KH3(C3O4)2,2Aq; but is less soluble, and more intensely sour, and forms modified octahedral crystals. The salt is occasionally sold under the names of ‘sal acetosellæ,’ ‘salt of sorrel,’ and ‘essential salt of lemons.’ Both are used to remove ink and iron stains from linen, to bleach the straw used for making bonnets, and, occasionally, in medicine, as a refrigerant.

Potassium, Oxide of. K2O. Prep. Burn pure potassium in a current of oxygen. White powder, rapidly absorbing water and forming the hydrate.

Potassium, Perchlorate of. KClO4. Syn. Potassæ perchloras, L. Prepared by projecting well-dried and finely powdered chlorate of potassium in small portions at a time, into warm nitric acid. The salt is separated from the ‘nitrate’ by crystallisation.

Potassium, Prus′siate of. See Potassium ferricyanide and FERROCYANIDE.

Potassium, Salicylite of. Formed by mixing salicylous acid (artificial oil of meadow-sweet) with a strong solution of hydrate of potassium; it separates, on agitation, as a yellow crystalline mass, which, after pressure in bibulous paper, is recrystallised from alcohol. Golden-yellow crystals, soluble in both water and alcohol; damp air gradually converts them into acetate of potassium and melanic acid.

Potassium, Silicate of. (Ure.) Syn. Potassæ silicas. Prep. Mix 1 part of powdered quartz or flint, or of fine siliceous sand with 2 parts of carbonate of potash, and fuse them in a Hessian crucible. Dissolve the mass in water, filter the solution and evaporate it to dryness—Dose, 10 gr. to 15 gr. in 6 or 8 oz. of water, twice a day. To dissolve gout concretions. An impure silicate of potash is used as a water-glass.

Potassium, Sulphate of. K2SO4. Syn. Potassæ sulphas (B. P., Ph. L., E., & D.). Prep. The sulphate of potassium of commerce is a secondary product of several chemical and manufacturing processes. Thus, the residuum of the distillation of nitric acid from nitre is dissolved in water, the solution neutralised with carbonate of potassium, and, after defecation, evaporation until a pellicle forms; it is then strained, or decanted, and set aside to crystallise. Or, the residuum is simply ignited, to expel excess of acid, and then dissolved and crystallised as before.

Prop., &c. Anhydrous, heavy, quartz-like crystals; permanent in the air; soluble in 12 parts of water at 60° and in 5 parts at 212° Fahr.; insoluble in alcohol; extremely nauseous, and bitter-tasted. It crepitates on the application of heat; fuses at a red heat, but loses nothing in weight. 100 gr. dissolved in distilled water, on the addition of chloride of barium and hydrochloric acid, furnish 132 gr. of sulphate of barium, dried at a red heat.

Potassium, Bisulphate of. KHSO4. Syn. Potassium-hydrogen sulphate, Acid potassium sulphate; Potassæ bisulphas. Prep. 1. (Anhydrous.) Neutral sulphate of potassium and oil of vitriol, equal parts; hot water, q. s. (not more) to dissolve; anhydrous bisulphate crystallises out, in long delicate needles, as the solution cools. If these are left for several days in the mother-liquor they are redissolved, and crystals of the ordinary hydrated bisulphate are deposited.

2. (Hydrated,)—a. (Ph. L. 1836.) Salt left in distilling nitric acid, 2 lbs.; boiling water, 3 quarts; dissolve; add of sulphuric acid 1 lb.; concentrate by evaporation, and set the liquid aside, so that crystals may form.

b. (Ph. D.) Sulphate of potassium (in powder), 3 oz.; sulphuric acid, 1 fl. oz.; mix them in a porcelain capsule, and expose it to a heat capable of liquefying its contents, until acid vapours cease to be evolved; powder the residuum, and preserve it in a well-stopped bottle.

Prop., &c. Sour and slightly bitter-tasted rhombic prisms; soluble in about 2 parts of cold and 1 part of boiling water, the solution exhibiting a strongly acid reaction. It is much employed, in lieu of tartaric acid, for the production of carbonic acid, in ‘gazogenes,’ &c.; also to adulterate cream of tartar and tartaric acid. According to Dr Paris, it forms a “grateful adjunct to rhubarb.”—Dose, 12 gr. to 1⁄2 dr., in solution, combined with rhubarb or bitters, as the neutral sulphate.

Potassium, Sulphide of. Syn. Sulphuret of potassium, Liver of sulphur†; Potassii sulphuretum (Ph. L., E., & U. S.), Hepar sulphuris (Ph. D.), L. Prep. 1. (Ph. E.) Sulphur, 1 oz.; carbonate of potassium, 4 oz.; mix, heat them in a covered crucible till they form a uniform fused mass; when cold, break it into fragments, and preserve it in well-closed vessels. The formulæ of the Ph. L. 1836 and Ph. U. S. are similar.

2. (Ph. D.) Sublimed sulphur, 4 oz.; carbonate of potassium (from pearlash, first dried, and then reduced to powder), 7 oz.; mix in a warm mortar, heat them in a Hessian crucible, as before, pour the fused mass into an iron cup, over which immediately invert a second vessel, to exclude the air, and, when cold, break the mass into fragments, and preserve it in a green-glass stoppered bottle.

Prop., &c. A hard, brittle, liver or greenish-brown coloured solid; inodorous whilst dry; soluble in water, forming a highly-fetid solution; and, in acids, evolving strong fumes of sulphuretted hydrogen; reaction, alkaline; exposed to the air, it is gradually converted into sulphate of potassa. As a medicine it is reputed diaphoretic, expectorant, and stimulant.—Dose, 2 to 6 gr., in solution, or made into pills with soap; in gout, rheumatism, liver affections, and various chronic skin diseases. Externally, made into a lotion and ointment. It is highly acrid and corrosive, and in large doses poisonous.

Potassium, Sulphocyanide of. KCNS, or KCyS. Syn. Sulpho-cyanuret of potassium; Potassii sulphocyanidum, P. sulpho-cyanuretum, L. Prep. 1. Ferrocyanide of potassium (anhydrous, or dried by a gentle heat), 46 parts; sulphur, 32 parts; pure carbonate of potassium, 17 parts; reduce them to powder, and very gradually heat the mixture to low redness in a covered iron crucible, which it will less than one half fill; remove the half-refrigerated and still soft mass, crush it, exhaust it with water, and evaporate the aqueous solution to dryness; powder the residuum, and exhaust it with hot alcohol or rectified spirit; the alcoholic solution will yield beautiful white crystals as it cools, and the residuum or mother-liquor may be evaporated for the remainder of the salt.

2. Cyanide of potassium, 3 parts; sulphur, 1 part; water, 6 parts; digest them together for some time, add 3 parts more of water, filter, evaporate, and crystallise.

Prop., &c. Long, slender, colourless prisms or plates, which are anhydrous, bitter-tasted, deliquescent, fusible, very soluble in both water and alcohol, and non-poisonous. It is chiefly used as a test for ferric oxide, for which purpose it is preferable to all other substances.

Potassium, Tartrate of. K2C4H4O6. Syn. Neutral tartrate of potassium, Tartrate of potassa, Neutral tartar, Soluble t.; Potassæ tartras (B. P., Ph. L., E., & D.), Kali tartarizatum†, L. Prep. (Ph. D.) Carbonate of potassium, 8 oz.; distilled water, 2 quarts; dissolve, and to the solution, whilst boiling hot, gradually add of bitartrate of potassium, in fine powder, 1 lb., or q. s., so that the liquid, after ebullition for a couple of minutes, ceases to change the colour of either blue or reddened litmus paper; next filter the liquid through calico, evaporate it until a pellicle forms on the surface, and set it aside to crystallise; after 12 hours collect the crystals, dry them on bibulous paper, and preserve them from the air. The formula of the Ph. L. 1836 is nearly similar.

Prop., &c. The crystals of this salt, which are obtained with difficulty, are right rhombic prisms, and are deliquescent. The salt of commerce is usually in the form of a white granular powder, which is obtained by simply evaporating the solution to dryness, with constant stirring. In this state it requires about 4 parts of cold water for its solution. Acids convert it into the bitartrate. As a medicine it acts as a gentle diuretic and aperient, and is valued for correcting the griping properties of senna and resinous purgatives. It is also antiscorbutic.—Dose, ⁄2 dr. to ⁄4 oz., in powder, or dissolved in water. The solution changes the colour neither of litmus nor turmeric. The addition of almost any acid throws down crystals of bitartrate of potassium, which generally adhere to the vessel. The precipitate occasioned by either chloride of barium or acetate of lead is dissolved by dilute nitric acid.

Potassium, Bitartrate of. KHC4H4O6. Syn. Acid tartrate of potassa, Super-tartrate of p., Cream of tartar; Cremor tartari, Potassæ bitartras (B. P., Ph. L., E., & D.), Potassæ super-tartras, Tartari crystalli, L. This well-known salt is deposited during the fermentation of grape juice as a crust on the sides of the casks or vats. In its unprepared or crude state it is called white or red tartar or argol, according to the wine from which it has been obtained. It is purified by boiling it in water, crystallisation, re-solution in water, and treatment with freshly burnt charcoal and aluminous clay, to remove the colour; the clear liquid is then decanted, whilst still hot, and allowed to cool slowly; the resulting crystals form the ‘cream of tartar’ of commerce.

Prop., &c. Small, translucent, gritty, prismatic crystals, irregularly grouped together; permanent in the air; requiring fully 100 parts of cold water, and about 15 parts of boiling water, for their perfect solution; the solution has a harsh, sour taste, and, like that of the tartrate, suffers spontaneous decomposition by keeping. Its solution reddens litmus. At a red heat it is converted into carbonate of potassium. Entirely soluble in 40 parts of boiling water; 40 gr., in solution, are neutralised by 30 gr. of crystallised carbonate of soda.—Dose. As an aperient, 1 to 3 dr.; as a diuretic, ⁄2 dr. to 1 dr.; as an antiscorbutic, 10 to 20 gr. frequently. It is much used to make a pleasant cooling drink (‘Imperial’), and in tooth-powders.

POTA′TO. This well-known and valuable article of food is the tuber of the Solanum tuberosum or esculentum, a plant which was introduced to this country by either Sir Francis Drake or Sir Walter Raleigh, towards the latter part of the 16th century. It is now extensively cultivated in all the temperate climates of the world. It yields a vast quantity of food on a small space of ground, but only about 1-7th part of the weight of the tuber is nutritious, and this is chiefly farinaceous. Its farina or starch is, however, accompanied by no inconsiderable portion of saline matter, more especially of potassa, which renders it highly antiscorbutic, and a powerful corrective of the grossness of animal food. When forming part of a mixed diet, perhaps no substance is more wholesome than the potato, and, certainly, no other esculent hitherto discovered appears equally adapted for universal use.

Boussingault gives the following as the average composition of the tubers of the potato:—

Moist Dry.

Water 75·9 —

Albumen 2·3 9·6

Oily matter 0·2 0·8

Fibre 0·4 1·7

Starch 20·2 83·8

Salts 1·0 4·1

100·0 100·0

Manuring experiments on potatoes in 1867-1869 show that on light soils a mixture of mineral superphosphate, crude potash salts, and ammonium sulphate, produces very beneficial results; on stiff soils nitrogenous manures have little effect. Further proof is given that manuring with common salt tends to decrease the yield.

Analyses, conducted by A. Stockardt, of potatoes grown in eight different years, show that those manured with salt invariably contain less starch than those unmanured, the decrease being from 10 to 20 per cent. of starch; the same effect is produced when the salt is mixed with other manures.

Under the microscope the cells are seen to be very sparingly fitted with starch grains.

Unmanured potatoes contained ·43 per cent. of sodium chloride in the dry substance, and those which had received a small dressing of common salt 1·34 per cent.

No certain rule can be laid down for ‘dressing’ potatoes. “If boiled, it may be that they require to be put into boiling water, or, may be, into cold, and either boiled quickly or slowly; but this you must find out. Choose them all about the same size, with a smooth skin, and when they are boiled and begin to crack, throw off the water immediately, as it only damages the root. When dressed let them stand near the fire, with a cloth over them, and serve them in their skins. Salt may be put into the water at the beginning. A watery potato will require quick boiling, and, sometimes, to be put into boiling water.” (Soyer.)

To retain the highest amount of nourishment in potatoes they should be ‘dressed’ with their skins on them. The bruised or damaged parts, worm-holes, &c., being removed with a knife, the dirt should be carefully cleaned out of the ‘eyes,’ and from the rough parts of the skins, by means of a brush and water, after which they should be well rinsed in clean water, and drained in a colander. If they are at all dry or shrivelled, they may be advantageously left to soak for 3 or 4 hours in clean cold water before cooking them. Potatoes ‘dressed’ in the skins have been found to be nearly twice as rich in potassa salts as those which have been first peeled. The skins are easily removed before sending them to table.

New potatoes should have their loose outer skin rubbed off with a cloth or stiff brush before being dressed or cooked.

Mashed potatoes are prepared by crushing, with the back of a spoon, or with a rolling-pin, the hot ‘dressed’ tubers, placed in a bowl or dish, or on a pie-board. A little milk, butter, and salt may be added to them at will, and they may be either at once ‘served up,’ or pressed into ‘forms,’ and first ‘browned off’ in the oven. Potatoes, if not soft and mealy, and well masticated, frequently escape the solvent action of the stomach, and pass off undigested, often to the serious derangement of the health. By mashing them this inconvenience is removed. The delicate, the dyspeptic, and the aged should take them in no other form.

Potatoes may be preserved so as to stand the longest voyages unchanged, by thoroughly desiccating them in an oven, or by steam heat. For this purpose the roots, either raw or three parts dressed, are generally first cut into dice of above ⁄4 inch square, to facilitate the operation. Under a patent granted to Mr Downes Edwards, Aug., 1840, the boiled potatoes are mashed and granulated by forcing them through a perforated plate before drying them. The granulated product, beaten up with a little hot milk or hot water, forms an excellent extemporaneous dish of mashed potatoes.

The microscopic detection of potato starch is easy. Instead of being round or oval, and with a central hilum, the starch grains are pyriform, with an eccentric hilum placed at the smaller end, and with well-marked concentric rings. A weak solution of liquor potassæ (one drop of the Pharmacopœia preparation to ten of water) swells them out greatly after a time; while wheat starch is little affected by potash of this strength; if the strength is 1 to 3 (as in the figs.) the swelling takes place very rapidly.

POT POURRI. [Fr.] A mixture of odorous flowers, roots, gums, &c., varied according to the taste of the operator, either mixed together dry, or in the fresh state preserved with salt. “The usual way of making it is to collect roses, lavender, and other sweet-scented flowers, as they blow; to put them into a large jar mixed (stratified) with salt, until a sufficient quantity has been collected; then to add to these such other odorous substances as may be required to form an agreeable perfume.” Among the substances thus added are—ambergris, benzoin, calamus root, cascarilla, cassia, cassia buds, cinnamon, civet, cloves, musk, musk seed, orange berries and flowers, orris root, pimento, storax, vanilla, yellow sandal wood, &c.

“Instead of the fresh flowers, dried roses are sometimes used, and, with the addition of some essential oils, these answer quite as well.” (Redwood.)

The following is a French formula:—Take the petals of the pale and red roses, pinks, violets, moss rose, orange flower, lily of the valley, acacia flowers, clove gilliflowers, mignonette, heliotrope, jonquils, with a small proportion of the flowers of myrtle, balm, rosemary, and thyme; spread them out for some days, and as they become dry put them into a jar, with alternate layers of dry salt mixed with orris powder, till the vessel is filled. Close it for a month and stir the whole up, and moisten it with rose water.

POT′TED MEATS. See Putrefaction and Potting (below).

POT′TERY. The mechanical operations connected with the manufacture of pottery (CERAMIC ART) do not come within the province of this work. The materials employed, in this country, to produce the best kind of earthenware (Staffordshire ware) are the fine white clays of Devonshire and Cornwall, and powdered chert or flint. This is brought to a perfectly homogeneous plastic mass with water, and in this state is fashioned upon the potter’s wheel and lathe, or by moulding, into all the varied objects of utility and ornament, which are made in this material. After the newly formed vessels and other articles have been dried by exposure in heated rooms, they are enclosed in clay cases (SEGGARS) and exposed to heat in a kiln, by which they arrive at a state (BISCUIT) which renders them fit for glazing; the patterns (if any) and, afterwards, appropriate vitreous materials having been applied to their surfaces, they are again placed in the seggars, and are again exposed in a kiln to a heat sufficiently high to fuse the newly applied compound, by which they acquire a uniform enamelled surface, and become fit for the market. Porcelain, or China, as it is commonly called, is manufactured in a nearly similar manner, but the materials are selected and the various processes conducted with corresponding skill and care.

The ornamental patterns are produced upon both Staffordshire ware and porcelain by a number of ingenious processes, among which printing, painting, and moulding are the principal. The colours employed are those which have been already referred to under Enamels.

The metallic lustres now so common on stoneware, &c., are given as follows:—

1. Gold lustre. Dissolve grain-gold, 1 dr., in aqua regia, ⁄4 oz.; to the solution add of metallic tin, 6 gr.; and when this is dissolved, pour it very gradually, with constant stirring, into a mixture of balsam of sulphur, ⁄2 dr.; oil of turpentine, 20 gr.; when the mass begins to stiffen, ⁄2 dr. more of oil of turpentine must be added, and well mixed in. More gold deepens and brightens the lustre; more tin turns it on the violet or purple.

2. Iron lustre. From a mixture of ‘muriate of iron’ (ferric chloride) and spirit of tar.

3. Platinum lustre. To a solution of platinum in aqua regia (platinic chloride) is added, drop by drop, a mixture of spirit of tar and balsam of sulphur in equal proportions, until by a trial the composition is found to give the required result. This gives the appearance of polished steel.

4. Silver lustre. The ammonio-chloride of platinum is reduced to an impalpable powder, ground up to the requisite consistence with a little spirit of tar, and at once applied with a brush.

The above lustres are applied, over an easily fusible glaze, to the outer surfaces only of the vessels, after which adhesion is produced by exposing the pieces to a slight degree of heat in the muffle. To give them their full beauty they must be rubbed with cotton, wool, or chamois leather, after the firing. See Alumina, Clay, Enamels, Gilding, Glazes, Kaolin, &c.

POT′TING. A term commonly applied to the operation or practice of preserving animal substances in a state fit for immediate use, in small pots or jars. The method of proceeding is, first, to mince the substance (previously well dressed, and carefully deprived of bones, sinews, skin, &c.), and, next, to pound it in a clean polished marble or iron mortar, along with a little butter and some cayenne pepper, or other suitable spice or sauce, until it forms a perfectly smooth paste; this is pressed into the pots, so as to about 2-3rds fill them, and clarified melted butter is then poured in to the depth of about 1-8th of an inch; the pots are, lastly, closely covered over, and kept in a cool situation. In this state their contents may be preserved for a year, or longer. Potted beef, ham, veal, poultry, game, anchovies, bloaters, salmon, &c., are commonly sold in the shops. They are all intended for relishes, and are spread upon bread in the same manner as butter.

POUDRE KOUSIQUE. [Fr.] A French nostrum, consisting of nitre and sulphur, of each 50 parts; charcoal and antimony, of each 1 part. It is divided into ⁄2-dr. doses, of which three are put into each packet. It is given to dogs in a ball of butter, to prevent the disorders to which they are liable.

POUDRE METALLIQUE. [Fr.] See Tooth cements.

POUDRE SUBTILE. [Fr.] See Depilatory.

POUDRETTE. [Fr.] Dried night-soil. The manure sold under this name is a compound of night-soil with clay, charcoal, or gypsum, made into balls or cakes. Its extensive use in Belgium, France, the United States of America, and, more particularly, in China, where it was first employed, has shown it to be the most fertilising and generally applicable of all the numerous substances used as manure. Unfortunately, the prejudices of Englishmen lead them to poison the air of their cities and towns, and the waters of their rivers, with a substance which, if rightly applied, would crown their fields with golden harvests, and drive pauperism from the land.

Tardieu, speaking of the men engaged in making poudrette, says:—“The action of the exhalations from the manure manufacturers is certainly not injurious. The workmen show actually no trace of sickness or disease which can be referred to the influence of these exhalations.”

That ‘poudrette’ is, however, occasionally liable to set up fermentation seems undeniable; and when this is the case, and large quantities of poudrette are stored within a small space, serious consequences may ensue.

Parent Duchâtelet cites the case of a vessel carrying poudrette to Guadaloupe, in which half the crew died, and the remainder were in a very low state of health on the arrival of the vessel at Guadaloupe, owing, as he affirms, to the exhalations given off by the poudrette.

POUL′TICE. Syn. Cataplasm; Cataplasma, L. An external application, generally extemporaneous, used to promote suppuration, allay pain and inflammation, resolve tumours, &c.

Poultices (cataplasmata) are generally prepared with substances capable of absorbing much water, and assuming a pulpy consistence, so as to admit of their application to any surface, however irregular. Their curative action principally depends upon the liquids with which they are moistened, and the heat retained by the mass. With this object they should never be heavy or very bulky, and should be frequently repeated, and lightly, but securely, bandaged on, to prevent displacement.

The addition of a little lard, olive oil, or, still better, glycerin, to a poultice, tends greatly to promote its emollient action, and to retard its hardening.

As the continued medication of the part with warmth and moisture, or with substances applied in the moist way, is the principal object to be attained in the application of poultices, a fold or two of lint or soft linen dipped in hot water, either simple or medicated, and covered with a piece of thin sheet gutta percha or india-rubber cloth, to prevent evaporation, may be often conveniently applied in their stead. A very elegant and useful substitute of this kind is sold under the name of ‘spongio piline.’ Its cleanliness, lightness, and ease of application has led to its extensive adoption by the medical profession.

The following formulæ embrace all the cataplasma of the Pharmacopœias:—

Poultice of Al′um. Syn. Cataplasma aluminis, L. Prep. (B. P., Ph. D. 1826.) Alum (in powder), 1 dr.; whites of 2 eggs; shake them together until they form a coagulum. Applied, between the folds of fine linen, to chilblains, sore nipples, inflamed eyes, &c.

Poultice, Anodyne. (P. Cod.) Syn. Cataplasma anodynum. Prep. Poppy heads, 1 oz.; dried leaves of henbane, 2 oz.; water, 24 oz. Boil, strain, and add to the liquor 4 oz. of emollient meals, to form a poultice.

Poultice, Antiseptic. (Fr. Hosp.) Syn. Cataplasma antisepticum. Prep. Barley flour, 6 oz.; powdered Peruvian bark, 1 oz.; water, q. s. Boil and, when cool enough, add camphor in powder, 1 dr.

Poultice, Astringent. (Foy.) Syn. Cataplasma astringens. Prep. Catechu, 1 oz.; powdered oak bark and barley meal, of each 1 oz.; cold water, q. s.

Poultice of Belladonna. (Dr Reece.) Syn. Cataplasma belladonnæ. Prep. Extract of belladonna, made in vacuo, 1 dr.; oatmeal, ⁄2 lb.; boiling water, q. s.

Poultice, Bran. Syn. Cataplasma furfuris. Prep. Fine bran, with one tenth of linseed meal, made into a poultice with boiling water. Mr Payne recommends, as a cheap hospital poultice, 3⁄2 pecks of pollard, 14 lbs. of bruised meal, and ⁄4 lb. of lard.

Poultice of Bread. Syn. Cataplasma panis, L. Prep. From crum of bread, soaked in hot water, slightly pressed, and then beaten up with a little lard, butter, or oil. Emollient. See Poultice, Linseed meal (below).

Poultice of Car′rot. Syn. Cataplasma dauci, L. Prep. 1. From the common esculent carrot, scraped fine, so as to form a pulp.

2. (Ph. D. 1826.) From the cultivated carrot boiled with a little water until it becomes soft enough to form a poultice. Anodyne and antiseptic. Used in foul and painful ulcers, burns, contusions, &c. That from the first formula is the more stimulant.

Poultice of Char′coal. Syn. Cataplasma carbonis (B. P., Ph. L.), C. c. ligni, L. Prep. 1. (Ph. L.) Soak bread, 2 oz., in boiling water, ⁄2 pint; to this add, by degrees, of linseed meal, 10 dr.; and, afterwards, of powdered (recently burnt) charcoal, 2 dr.; lastly, sprinkle on the surface of the poultice powdered charcoal, 1 dr. As an application to fetid and gangrenous sores; frequently renewed.

2. (B. P.) Wood charcoal, ⁄2 oz.; bread, 2 oz.; linseed meal, 1⁄2 oz.; boiling water, 10 oz.; soak the bread in the water near the fire, add the linseed meal and half the charcoal, stirring to a soft poultice, sprinkling the remainder of the charcoal on the surface.

Poultice of Chlo′′ride of So′da. Syn. Cataplasma sodæ chlorinatæ (B. P., Ph. L.), L. Prep. 1. (Ph. L.) Boiling water, 6 fl. oz.; linseed meal, 4⁄2 oz.; mix gradually, then add of solution of chlorinated soda, 2 fl. oz. Applied to foul ulcers, gangrenous parts, &c.

2. (B. P.) Solution of chlorinated soda, 1; linseed meal, 2; boiling water, 4; add the linseed meal gradually to the water, stirring constantly, then mix the solution of chlorinated soda.

Poultice, Compound Farina. Syn. Cataplasma farinæ compositum. Prep. Rye flour, 1 lb.; old yeast, 4 oz.; salt, 2 oz.; hot water, q. s.

Poultice, Cummin. (L. Ph. 1788.) Syn. Cataplasma cumini. Prep. Cummin seeds, 1 lb.; bay berries, scordium leaves, serpentaria root, of each 3 oz.; cloves, 1 oz.; to be powdered together and mixed with thrice their weight of honey.

Poultice, Discutient. Syn. Cataplasma discutiens. Prep. Barley meal, 6 oz.; fresh hemlock, 2 oz.; vinegar, q. s. Boil and add sal ammoniac, ⁄2 oz. (Fr. Hosp.) The same, with 2 dr. of acetate of lead added.

Poultice, Effervescing. Syn. Cataplasma effervescens. Prep. Fresh wort thickened with oatmeal, and a spoonful of yeast added.

Poultice, Emetic. Syn. Cataplasma emeticum. Prep. Bruised groundsel (Senecio vulgaris) applied over the stomach produces vomiting.

Cataplasma of Fig. Syn. Cataplasma fici. Prep. A dried fig, roasted or boiled (sometimes in milk), is frequently applied to gum-boils, &c.

Poultice, Foxglove. (Mr Alland.) Syn. Cataplasma digitalis. Prep. A strong decoction of foxglove, with bread-crum, or linseed meal, q. s.

Poultice, Galbanum. Syn. Cataplasma galbani. Prep. Lily roots, 4 oz.; figs, 1 oz.; boil till soft, and bruise them with 1⁄2 oz. of onions and ⁄2 oz. of galbanum, triturated with yolk of egg and a sufficient quantity of linseed meal.

Poultice, Galvanic. (Recamier.) Syn. Cataplasma galvanicum. It consists of cotton wadding containing a layer of very thin zinc plates, and another layer of copper ones. This pad, conveniently quilted, is enclosed in a bag, one face of which is of quilted calico, the other of impermeable tissue. The natural perspiration, confined by the impermeable tissue, excites galvanic action between the metals.

Poultice of Hem′lock. Syn. Cataplasma conii (B. P., Ph. L.), L. Prep. 1. (Ph. L.) Boiling water, ⁄2 pint; linseed meal, 4⁄2 oz., or q. s.; make a poultice, and on this spread of extract of hemlock (Ph. L.), 1 oz., first softened with a little hot water. Anodyne. In irritable and painful cancerous, scrofulous, and syphilitic sores, tumours, &c.

2. (B. P.) Hemlock leaf, in powder, 1 oz.; linseed meal, 3 oz.; boiling water, 10 oz.; mix the ingredients, then add them to the water gradually, constantly stirring.

Poultice, Henbane. Syn. Cataplasma hyoscyami. The same as Poultice of poppy.

Poultice, Hop. (Dr Trotter.) Syn. Cataplasma humuli. Hops softened with hot water. To foul ulcers.

Poultice, Iodine. Syn. Cataplasma ioduretum. To a common poultice add solution or tincture of iodine.

Poultice, Lead. Syn. Cataplasma plumbi. Prep. Goulard water, 1 lb.; bread crum, q. s.

Poultice, Lily. Syn. Cataplasma lilii. The pulp of the white lily boiled and bruised.

Poultice, Lime. Syn. Cataplasma calcis. Prep. Slaked lime, 2 oz.; oatmeal, 2 oz.; lard, 4 oz. Formerly used at Bath Hospital.

Poultice of linseed Meal. Syn. Cataplasma lini (B. P., Ph. L.), L. Prep. 1. (Ph. L.) To boiling water, ⁄2 pint, add, gradually, constantly stirring, of linseed meal, 4⁄2 oz., or q. s. Emollient. Used to promote the suppuration or ‘ripening’ of tumours. A little oil or lard should be added, and some smeared over the surface as well, to prevent its getting hard. For small ‘gatherings,’ as of the fingers, a little chewed bread and butter is an efficient and convenient substitute.

2. (B. P.) Linseed meal, 4; olive oil, ⁄2; boiling water, 10; mix the linseed meal with the oil, add the water gradually, constantly stirring.

Obs. Linseed meal prepared from the cake, from which the oil has been expressed, is less adapted for poultices than that prepared from the unpressed, whole seed. The latter is ordered in the Ph. L.

Poultice, Malt. (Guy’s Hosp.) Syn. Cataplasma bynes. Prep. Ground malt, with yeast, q. s., to form a poultice; to be applied warm.

Poultice, Maturative. (L. 1745.) Syn. Cataplasma maturans. Prep. Pulp of figs, 4 oz.; resin ointment, 1 oz.; strained galbanum, ⁄2 oz.

Poultice of Mus′tard. Syn. Cataplasma sinapis (Ph. L.), L. Prep. 1. (B. P., Ph. L.) Linseed meal and powdered mustard, of each 2⁄2 oz., or q. s.; boiling water, ⁄2 pint; mix as before.

2. (Ph. L. 1836.) As the last, but substituting boiling vinegar for water. Used as a powerful counter-irritant, stimulant, and rubefacient; in low fevers, apoplexy, coma, &c., where there is a determination of blood to the head; in deep-seated inflammatory pains, neuralgic pains, &c. It should not be left on long enough to raise a blister. See Plasters.

Poultice, Onion. Syn. Cataplasma cepæ. Prep. Onions roasted and mashed.

Poultice of Pop′py. Syn. Cataplasma papaveris, L. Prep. 1. (P. Cod. 1839.) A strong decoction of poppies, thickened with crum of bread. Anodyne.

Poultice, Potash, Acetate of. Syn. Cataplasma potassæ acetatis; Cataplasma neutrale. Prep. Acetate of potash, 1 oz.; water, 1 pint; crum of bread, q. s. To ill-conditioned sores.

Poultice of Po′tato. Syn. Cataplasma solani tuberosi, L. Prep. From the raw potato, scraped or grated fine. A popular application to fresh bruises, extravasations, burns, scalds, &c.

Poultice of Potato Starch. (P. Cod.) Syn. Cataplasma feculæ. Prep. Potato starch, 2 oz.; mix with a little cold water, add to it 20 oz. of boiling water, and boil for an instant. Cataplasms of rice and wheat starch are made in the same manner.

Poultice, Pradier’s. Syn. Pradier’s cataplasma; Cataplasme de Pradier, Fr. Prep. Take of balsam of Mecca, 6 dr.; rectified spirit, 16 oz.; dissolve; next, separately, take red cinchona bark, sarsaparilla, and sage, of each 1 oz.; saffron, ⁄2 oz.; rectified spirit, 32 oz.; digest for 48 hours, and filter; mix the two liquors; add to them twice their weight of lime water. In gout; 2 fl. oz. are sprinkled on the surface of a hot linseed-meal poultice sufficiently large to surround the affected part. It is said that the Emperor Napoleon gave £2500 for this receipt.

Poultice of Pyroligneous Acid. (Dr Reece.) Syn. Cataplasma acidi pyrolignosi. Prep. Bran, 1 lb.; linseed meal, 1 oz.; impure pyroligneous acid, q. s. For scrofulous ulcers; occasionally 30 minims of tincture of perchloride of iron, and 3 dr. of extract or powder of hemlock, are added.

Poultice of Red Wine. (Gl. Hosp.) Syn. Cataplasma vini rubri. Prep. Linseed meal, 1⁄2 oz.; boiling water, 5 oz.; stir it over a slow fire for a minute, remove, and add 2 oz. of red wine.

Poultice, Roasted Apple. Syn. Cataplasma mali. The soft pulp of roasted apple, applied to inflamed eyes. Other ingredients are sometimes added.

Poultice, Rose. Syn. Cataplasma rosæ. Prep. Powdered alum, 30 gr.; confection of roses, 4 oz.; mix.

Poultice of Sea-wrack. (Dr Russell.) Syn. Cataplasma fuci. Prep. Fresh bladder fucus (sea-wrack) bruised. Applied to glandular tumours, &c.

Poultice, Sim′ple. Syn. Cataplasma simplex, L. Prep. (Ph. D. 1826.) Powder for a cataplasma and boiling water, of each q. s. to form a poultice, the surface of which is to be smeared over with olive oil. Emollient. Bread poultice and linseed-meal poultice are now generally called by this name. See Powder (Poultice).

Poultice of Slippery Elm. Cataplasma ulmi. The powdered bark of the slippery elm (Ulmus fulva) mixed with a sufficient quantity of hot water.

Poultice of Soap. Syn. Cataplasma saponis, L. Prep. From white soap (scraped or sliced), 1 oz.; boiling water, ⁄4 pint; dissolve, and add crum of bread, q. s. As an application to scalds and burns.

Poultice, Sorrel. Syn. Cataplasma oxalis. Prep. Bruised sorrel leaves, mixed with oatmeal and beer.

Poultice, Stimulating. (Dr Hugh Smith.) Syn. Cataplasma stimulans. Prep. Rye flour, 1 lb.; old yeast, 4 oz.; common salt, 2 oz.

Poultice, Sulphate of Lime. (Blizard.) Syn. Cataplasma calcis sulphatis. Prep. Paris plaster mixed with water to a soft paste, and applied before it hardens. Formerly applied to ulcers to form an artificial scab; now occasionally used to afford mechanical support in some surgical cases.

Poultice of Sulphate of Soda. (Kirkland.) Syn. Cataplasma sodæ sulphatis. Prep. Sulphate of soda, 1 oz.; boiling water, ⁄2 lb.; crum of bread, a sufficient quantity.

Poultice to cause Suppuration. (E. Ph. 1774.) Syn. Cataplasma suppurans. To an emollient cataplasm add bruised onions, 1⁄2 oz.; basilicon ointment, 1 oz.

Poultice of Tannate of Lead. (G. Ph.) Syn. Cataplasma ad decumbitum; Plumbum tannicum pultiforme. Prep. Boil 2 oz. Of oak bark in sufficient water to yield 10 oz. of strained decoction; add to this 1 oz. (by weight) of liquid subacetate of lead, collect the precipitate on a filter, and put it into a bottle with 2 dr. of rectified spirit.

Poultice, Tonic. (G. Hosp.) Syn. Cataplasma tonicum. Prep. Powdered bark, 1 oz.; charcoal, 1 oz.; camphor, 1⁄2 dr.; oil of turpentine, q. s.

Poultice, Turnip. Syn. Cataplasma rapi. Prep. Peel turnips, boil them till soft, beat them to a pulp, and apply warm.

Poultice, Turpentine. (Dr Reece.) Syn. Cataplasma terebinthinæ. Prep. Oil of turpentine, 2 dr.; olive oil, 1 oz.; linseed meal, 1 oz.; oatmeal, 4 oz.; boiling water, q. s. To indolent ulcers, and, with more turpentine, to deep burns, scalds, and chilblains.

Poultice of Vin′egar. Syn. Cataplasma aceti, L. Prep. From crum of bread soaked in vinegar. Applied cold in bruises, extravasations, &c., especially black eyes. Verjuice is often employed in the same way.

Poultice of Walnut Leaves. (Perfect.) Syn. Cataplasma juglandis. Prep. The fresh leaves of walnut bruised and mixed with honey. Applied over the abdomen as a vermifuge.

Poultice of Yeast. Syn. Cataplasma fermenti (B. P., Ph. L.), C. f. cerevisiæ, L. Prep. 1. (Ph. L.) Beer yeast and water at 100° Fahr., of each 5 fl. oz.; mix, stir in flour, 1 lb., and place it near the fire until it rises. In gangrenous or foul ulcers; to correct the fetor of the discharge, and to hasten the sloughing.

2. (B. P.) Beer yeast, 6; flour, 14; water (at 100° Fahr.), 6; mix. Place the mass near the fire till it rises.

POUL′TRY. Domestic birds, which are propagated and fed for the table, and for their eggs, feathers, &c.

The poultry of this country are the common domestic fowl, the turkey, the duck, and the goose; to which some writers add the guinea-fowl and the peacock. Of these, the first is the most generally useful. Though a native of India, it accompanies man through almost every gradation of civilisation and climate, and flourishes almost everywhere, when properly secured from the inclemency of the weather, and allowed an ample supply of fresh air, with proper food. For the production of abundance of eggs it must, however, be well fed and warmly lodged. The hen-roosts and poultry-houses should be well protected from the weather, and their temperature should be duly maintained by proximity to the stables, cow-houses, or dwelling-house, and, in cold weather, by the employment, when necessary, of artificial heat. The food should also contain an ample supply of nitrogenous matter, for without this how can it be expected that hens can produce abundance of eggs, which are peculiarly rich in nitrogen? The ‘greaves’ of the tallow-chandlers, and such-like substances, are hence excellent additions to the ordinary food of poultry. But it is not sufficient merely to supply poultry with abundance of food and warmth; it is equally necessary that they should have ample space for exercise and recreation. This space “should always contain living plants of various kinds, and some gravelly or sandy soil; because worms, snails, as well as, occasionally, grass and herbage, form a part of the food of poultry; and sand or gravel is swallowed by them for the purpose of promoting digestion. Hence, no healthy poultry can ever be reared in towns, however much the natural food may be imitated by the supply of animal matters, herbage, and sand.” (Loudon.)

POUNCE. Powdered gum sandarac generally passes under this name. It is used to prepare parchment for writing on, and to prevent ink from spreading upon paper after erasures. Powdered cuttle-fish bone is occasionally employed in the same way. Both are applied to the surface by means of a cylindrical roll of list called a ‘rubber.’ Packers rub the surface of porous and greasy woods, as the heads of boxes, cases, casks, &c., with whiting or powdered resin, to make them bear the ink. The coloured powders used by pattern drawers, for sprinkling over pricked papers, are also called ‘pounce.’ For liquid pounce, see Marking ink.

POWDER. Syn. Pulvis, L. Powders are divided by pharmaceutical writers into two classes—simple and compound. The first are prepared by simple pulverisation; the second by the admixture of two or more simple powders. For use the appropriate doses are separately weighed, and placed in separate papers. They are usually exhibited in a little honey, sugar, or milk, either taken from a spoon or made into an electuary or bolus, and swallowed in the semi-solid form. Metallic and other heavy powders are best taken in the latter state. Very active substances should be, in all cases, mixed with some inert powder, as that of starch, gum, liquorice, or marshmallow, at the time of ‘dispensing’ them.

“This form of preparing medicines is the simplest, and perhaps the least objectionable; but it is not applicable to all the articles of the Materia Medica. Those remedies which are very unpleasant to the taste; those which deliquesce rapidly when exposed to the air, or are very volatile; and those which require to be given in very large doses, or which are not diffused readily in water, cannot, with propriety, be administered in the form of powder. Some substances cannot be reduced to powder unless they be very much dried, and the heat necessary for that purpose alters their properties.” Nor can we “be surprised that a great alteration should be effected in a short time by the action of the air on so great an extension of surface as takes place in the operation usually adopted for reducing drugs to a fine powder.” (A. T. Thomson.)

In this country compound powders appear to be a favourite form of medicine in the diseases of infancy and childhood.

“It is necessary that whatever we order to be reduced to powder should be rubbed through a fine sieve, so that the impurities and coarser parts may be separated; and it is needful that most powders should be recently prepared, and not too long kept.” (Ph. L.)

As nearly all powders suffer by exposure to the air and light, they should be preserved in closely-corked opaque or green-glass bottles, or in tin canisters from which the external air is carefully excluded. See Pulverisation, &c.

Powder, Algaroth’s. See Antimony, Oxychloride.

Powder of Al′oes (Compound). Syn. Pulvis aloës compositus (Ph. L.), P. aloës cum guaiaco, L. Prep. (Ph. L.) Socotrine or hepatic aloes (in powder), 1⁄2 oz.; guaiacum (in powder), 1 oz.; compound cinnamon powder, ⁄2 oz.; rub them together. A warm, sudorific purgative.—Dose, 10 to 20 gr.

Powder of Aloes with Canel′la. Syn. Aloetic powder, Holy bitter†; Hiera picra†, Pulvis aloes cum canellâ, L. Prep. From powdered Socotrine or hepatic aloes, 4 parts; powdered white canella, 1 part. Uses and dose, as the last.

Obs. Once a highly popular remedy. It was originally made into an electuary with honey, and in this form was frequently called ‘HIERA LOGADII,’ It is still a favourite in domestic medicine and veterinary practice. The principal objection to both this and the preceding preparation is the nauseous flavour of the aloes, which is ill concealed by the aromatics. The ‘HIERA PICRA’ for farriers is usually made with the cheapest Cape aloes.

Powder of Aloes with Iron. (L. Ph. 1788.) Syn. Pulvis aloeticus cum ferro. Prep. Aloes, 1⁄2 oz.; myrrh, 2 oz.; sulphate of iron, 1 oz.; dried extract of gentian, 1 oz.

Powder of Al′um (Compound). Syn. Styptic powder; Pulvis stypticus, P. aluminis compositus (Ph. E.), L. Prep. (Ph. E.) Alum, 4 oz.; kino, 1 oz.; mix them, and reduce them to fine powder. Astringent and styptic.—Dose, 5 to 15 gr.; in diarrhœa, profuse menstruation, &c. Externally, in hæmorrhages, &c.

Powder, Alum, Opiated. (Bouchardat.) Syn. Pulvis aluminis opiatus. Prep. Alum, 1 dr.; sugar, 1 dr.; opium, 4 gr.; mix for 12 powders. 2 or 3 daily in obstinate diarrhœas and passive hæmorrhages.

Powder of Alum with Capsicum. (Dr Turnbull.) Syn. Pulvis aluminis cum capsico. Prep. Alum, 3 parts; concentrated tincture of capsicum, 1 part; mix, dry, and triturate again. Applied to the tonsils.

Powder of Alum with Gum. (Frankel.) Prep. Alum, gum tragacanth, of each equal parts. Applied to sore breasts.

Powder of Alum with Starch. (St. Th. Hosp.) Syn. Pulvis aluminis cum amylo. Prep. Alum and starch, equal parts. In insufflation of rhinorrhœa.

Powder of Ambergris with Musk. (Bat. Ph.) Syn. Pulvis ambergriseæ moschatus. Prep. Ambergris, 6 dr.; musk, 1 dr.; oil of cinnamon, 2 scruples; refined sugar, 11⁄2 oz.; mix.

Powder, Ammoniated Aromatic. Syn. Pulvis ammoniatus aromaticus; Leayson’s ammoniacal collyrium. Prep. Muriate of ammonia, 1 dr.; slaked lime, 1 oz.; charcoal, 15 gr.; cinnamon, 15 gr.; cloves, 15 gr., bole, ⁄2 dr. Put them into a bottle and moisten with a little water.

Powder of Ancho′vy. Syn. Pulvis clupeæ encrasicoli, L. Prep. Pound anchovies to a paste, then rub them through a sieve, and add enough flour to make a dough, which must be rolled out into thin slices and dried by a gentle heat in a stove; it is, lastly, powdered and bottled. Colouring is frequently added. Chiefly used to make sauces. British anchovies are frequently substituted for the genuine fish.

Powder, Anthrakokali, Compound. Syn. Pulvis anthrakokali, compound. Prep. Anthrakokali, 2 gr.; washed sulphur, 6 gr.; mix. For 1 dose.

Powder, Anthrakokali, Simple. (Poyla.) Syn. Pulvis anthrakokali simplex. Prep. Anthrakokali, 2 gr.; liquorice powder, 6 gr.; mix. For 1 dose.

Powder, Antiepileptic. Syn. Pulvis antiepilepticus (E. Ph., 1744.) Prep. White dittany, pæony, valerian, mistletoe of the oak, equal parts.—Dose, 10 to 6 gr. (Behrends.) Prep. Valerian, 4 dr.; magnesia, muriate of ammonia, oil of cajeput, of each 1 scruple.—Dose. A teaspoonful three times a day. Dr Paris says the following was used successfully by a Dutch empiric:—Sulphur, 1 scruple; sulphate of potash, 10 gr.; rhubarb, 5 gr.; nutmeg, 2 gr.; mix. (Germ. Hosp.) Prep. Oxide of zinc, 16 gr.; carbonate of magnesia, 48 gr.; oleo-saccharum of cajeput, 3 dr. Mix for 8 doses. Poudre de Ragolo. Oxide of zinc, 10 gr.; valerian, mistletoe, sugar, orange leaves, of each 4 dr.; magnesia, 2 scruples; oil of cajeput, 2 scruples; a teaspoonful three times a day. Pasquier prescribes—Wall crop, 10 gr.; gum Arabic, 10 gr.; 1 to 4 powders daily for eight times. Sommer’s specific consists of—Wall crop, 6 to 10 gr.; oleo-saccharum of mint, 8 gr.; one morning and evening for six times. See Pulvis artemisiæ saccharatus. The Poudre de Guttète consists of mistletoe, 2 parts; white dittany, 2; pæony root and seeds, 2; prepared coral, 1; elk’s hoof, 2; seeds of orache, 2. Given in doses of a few grains in convulsions of infants, or in larger doses for epilepsy.

Powder, Antihydrophobic. (Dr Mead.) Syn. Pulvis antilyssus. Prep. Ash-coloured ground liver-wort (Pettidea canina), ⁄2 oz.; black pepper, 2 dr.; mix, and give a fourth part every morning for 4 times.

Powder, Antimo′′nial. Syn. Fever powder, Lisle’s p., James’s p.; Pulvis Jacobi, Pulvis antimonialis (B. P., Ph. E., & D.), Pulvis antimonii compositus (Ph. L.), L. Prep. 1. (Ph. L.) A mixture of tersulphide of antimony, 1 lb., and hartshorn shavings, 2 lbs., is reduced to powder, thrown into a crucible heated to whiteness, and stirred constantly until vapour no longer rises; the calcined mixture is then rubbed to powder, again put into the crucible, and the heat gradually increased to whiteness, and maintained so for 2 hours; the residuum is, lastly, reduced to a very fine powder.

2. (Ph. E.) From sulphide of antimony and hartshorn shavings, equal weights; as the last.

3. (Ph. D.) Tartarised antimony, 4 oz., is dissolved in water, ⁄2 gall., and added to solution of phosphate of soda, 4 oz., in water, 1 quart; a solution of chloride of calcium, 2 oz., in water, 1 quart, and to which solution of ammonia (Ph. D.), 4 fl. oz., has been added, is next poured in, and the whole boiled for 20 minutes; the precipitate is then collected on a calico filter, and washed with hot distilled water, until the liquid which passes ceases to give a precipitate with a weak solution of nitrate of silver; it is, lastly, dried by a steam or water heat, and reduced to a fine powder.

4. (B. P.) Oxide of antimony, 1; precipitated phosphate of lime, 2; mix.—Dose, 2 to 6 gr.

Uses, &c. Febrifuge and diaphoretic. Intended as a substitute for the proprietary and more expensive James’s powder.—Dose, 3 to 10 or 12 gr., or more, repeated every fourth or fifth hour until diaphoresis is set up; in fevers, rheumatic affections, chronic skin diseases, &c. It is a very uncertain and variable compound, unless it has been carefully prepared. Dr Elliotson exhibited it in doses of 100 gr. without producing any sensible effect. A spurious article, made by triturating 1 oz. of tartar emetic with 18 or 19 oz. of burnt hartshorn, is frequently sold for it in the shops. See Antimonious acid and James’s powder.

Powder, Antispasmodic. (P. Cod.) Syn. Pulvis antispasmodicus. Prep. Cyanide of zinc, 3 gr.; calcined magnesia, 24 gr.; cinnamon, 12 gr.; mix. For 6 doses.

Powder, Antispasmodic. (Jourdan.) Syn. Pulvis antispasmodicus. Prep. Valerian, 1 oz.; oxide of zinc, 1 scruple; musk, 8 gr.; mix.

Powder, Aromat′ic. See Powder, Compound Cinnamon.

Powder, Arsen′ical. See Powder, Escharotic.

Powder of Asarabac′ca (Compound). See Snuff (Cephalic).

Powder, Astrin′gent. Syn. Pulvis astringens, P. stypticus, L. Prep. 1. From Aleppo galls and burnt alum, in fine powder, equal parts. Used in piles, soft polypi of the nose, chilblains, &c.