The Cestodes, or Tape-worms

Tape-worms in the mature condition inhabit the intestines of vertebrate animals, and are usually conspicuous for their long, tape-like appearance and jointed character. In the juvenile or larval state they infest the various organs, except the interior of the intestinal canal, of both vertebrates and invertebrates, and in this condition are so diminutive and inconspicuous that until a comparatively recent period they for the most part remained unnoticed, and when known their relationship with the mature forms was not recognized.

The mature tape-worm, as ordinarily observed, is a long, soft, flat, white worm, which from its resemblance has received its familiar name. It has a small head, succeeded by a short, more slender neck gradually widening into the body, which is divided transversely into segments. These, which are usually called joints or links, and also named proglottides, are so many individuals, and finally become separated to hold an independent existence. The tape-worm clings to the mucous membrane of the intestine by its head, which is provided for the purpose with suckers, and in many cases also with circlets of hooks. The segments of the body are incessantly produced by gradual growth and successive division of the neck, and as they enlarge they become more distinct and develop within a bisexual generative apparatus for each. The worm has neither mouth nor intestine, but is nourished by imbibition from the surrounding liquid in which it lies constantly bathed. A pair of longitudinal vessels commences in the head and extends throughout the body, one on each side, and in some genera is joined by a transverse vessel at the fore and back part of every segment. The mature segments have no body-cavity, but are occupied with a complex bisexual generative apparatus, which is self-impregnating. Finally the uterus, usually much ramified, becomes especially conspicuous through distension with eggs, and the rest of the organs for the most part become atrophied. The ripe segments successively detach themselves from those in advance, often singly and not infrequently several linked together. In this condition, often in lively movement, they are discharged with the feces, and thus commonly render themselves obvious to their host. Subsequently they may continue to live a brief period externally in a non-parasitic condition. Ordinarily, in moist excrement, or in water or similar materials, they will remain alive for several days.

After the discharge of the tape-worm segments, together with the eggs which had been previously laid by the latter and those still contained within them, any or all may be swallowed by animals feeding in places where the infected excrement has been deposited. When the proglottides and eggs are taken into the stomach they are digested and the embryos or proscolices are liberated.

The embryo or proscolex of the tape-worm is a microscopic spherical or oval body, provided at one pole with three pairs of divergent spicules, by which it is enabled to penetrate the walls of the stomach or intestine of its host. From these positions the embryo migrates either directly or through the blood-vessels to some other organ, most frequently the liver or the muscles. Having reached its destination, it becomes fixed in position, and for a time remains comparatively quiescent, but undergoes further development. The embryo loses its spicules and is transformed into the larval form or scolex. In most species of tape-worms the scolex is simple or individual in character, and consists of a head like that of the parent or mature worm, with a neck ending in a capacious cyst, within which the head and neck are inverted. In this form the scolex is contained in a sac of connective tissue induced by the presence of the parasite. Such sacs, frequently observed imbedded in the flesh, liver, lungs, and other organs of animals, are familiarly known as measles. In this condition the scolices of certain tape-worms have long been known, but as their relationship was not recognized, they were viewed as distinct species of parasites and described as cysticerci. In other species of tape-worms the scolex is of compound character; that is to say, the embryo in its further development gives rise to the production of one or more groups of individuals in conjunction. The compound scolex thus forms a sac or a group of sacs, the basis of hydatid tumors. These occur of various sizes, even up to that of a child's head, and may occupy any organ of the body. They consist of a spherical sac or group of sacs, simple in character or containing others, ranging in size from that of a mustard-seed to that of a marble, or larger to that of a walnut, enclosed in an envelope of connective tissue induced by the presence of the parasite. The sacs are filled with liquid, and have, attached within or free and floating, or less frequently attached without, variable numbers of little white grains, which on examination with the microscope exhibit the same constitution as the simple scolex above described. As in the case of the cysticerci of measles, the scolices of hydatids have long been known, but as their relationship with the mature forms was unrecognized until lately, they were regarded as distinct parasites and described as echinococci and coenuri. Sometimes the compound scolex fails in development further than the production of the sacs, which then constitute the so-called acephalocysts.

Measles with their occupants, when retained in the muscles or other organs, ordinarily undergo no further development, but ultimately, after some months to a year or two, undergo degradation. The larva or scolex dies and atrophies; the measle degenerates, and often becomes the focus of calcareous deposit, shrinks to a little cicatrix, and may finally disappear. Of a more serious nature is the tape-worm embryo which produces the hydatid tumor. With the increase of this, proportioned to the production of sacs and scolices, it may become so large as greatly to interfere with the function of the organ it occupies, and according to the nature of this organ will be the gravity of the affection.

When, however, the flesh or other parts of animals affected with measles or hydatids containing active scolices are used as food in a raw or insufficiently cooked state, the meats are digested in the stomach and the scolices liberated to pursue their further development. Passing into the small intestine, the active scolex everts its head from its caudal sac, which atrophies and disappears, and the parasite attaches itself to the mucous membrane, and rapidly develops and grows into the conspicuous and familiar form of the adult tape-worm. The duration of life of the latter while maintaining its position in the intestine is uncertain, but under favorable circumstances it commonly continues for years, and thus, with the incessant production of ripe segments charged with eggs, it becomes a constant focus of infection.

Three species of tape-worm in the mature condition are common parasites of man, living in the small intestine. They are the Tænia saginata, Tænia solium, and Bothriocephalus latus.

TÆNIA SAGINATA.—SYNONYMS: Tænia mediocanellata; Beef tape-worm; Unarmed tape-worm; Fat tape-worm.

Larval condition: Cysticercus saginata; Beef measle-worm.

This, which is now regarded as the most common tape-worm of man, is named the beef tape-worm because it is derived from the beef used as food. In the mature condition it lives only in the small intestine of man, and in the juvenile condition it lives in the ox. Its frequency is proportioned to the prevalence of the custom of eating beef in a raw or insufficiently cooked state, conjoined with the careless habit of leaving human excrement in pastures where it is accessible to cattle.

The mature beef tape-worm is commonly observed as a soft, yellowish-white, thickish, band-like worm, ranging from six to twenty feet or more in length. The head, about the size of a yellow mustard-seed, is rounded quadrate and provided with four equidistant hemispherical suckers. Succeeding the head is a short, slightly narrower, flattened neck, which merges into the gradually widening and segmented body. The segments, at first narrow fore and aft and several times wider than the length, become successively larger, proportionately longer, more distinct, and quadrate in outline; and finally the length may exceed the breadth two or three times. A full-grown tape-worm may possess twelve hundred segments and more, and specimens are recorded as reaching a length of thirty feet. The larger segments measure from a quarter of an inch to an inch long and from three to four lines wide. The larger or riper segments exhibit on one border, irregularly alternating on the two sides, at or near the middle, a papilla in which is the external aperture of the genital apparatus. In the fully-ripe segments the uterus, distended with eggs, may be obscurely seen through the wall of the body, but is rendered more visible by drying the segments, moderately compressed, between two pieces of glass. It appears as a long, narrow, white or brownish median line or tube, giving off laterally numerous short, transverse, more or less branching tubes.

The worm in its usual position lies along the course of the intestine in loose coils, and exhibits lively movements, alternately shortening and elongating, expanding and contracting the head, and protruding and retracting the suckers. The ripe segments spontaneously detach themselves, and may be found scattered along the large intestine ready to be discharged with the excrement, or, as is sometimes the case, they may spontaneously creep from the anus. Rarely more than a single worm infests a person at the time. The species is of rapid growth. According to Perroncito, quoted by Cobbold, a mature worm was reared from a beef measle, swallowed by a student, in fifty-four days.

It is estimated that the number of eggs in the mature segments of the beef tape-worm amounts to about 35,000. As the full-grown worm may consist of 1200 segments, and there is reason to believe these are renewed several times annually, we learn that the whole number of eggs produced by a single individual is enormous. The ripe segments, attached to the parent or becoming spontaneously detached, lay their eggs in the intestine to be discharged with the feces. When more or less emptied they shrink and appear reduced in size, and in this condition are expelled or spontaneously creep from the anus. If the ripe segments are forcibly expelled and are alive, they will lay their eggs in the feces externally. The ripe eggs are brown, oval, about 0.03 mm. long, and have a thick shell, with an outer vertically striated envelope.

As previously intimated, the common source of the beef tape-worm in man is the use of raw or insufficiently cooked beef affected with measles. The ox becomes infested by swallowing the eggs, or, it may be, even the entire segment, of a tape-worm deposited with feces in the pastures of cattle. The measles usually occur in the muscles, including the heart, though they have also been noticed in the liver and lungs. They appear, in beef, as oval, whitish bodies from the size of a mustard-seed to that of a pea. They consist of a sac of connective tissue containing the larval tape-worm or cysticercus. Measles under ordinary circumstances are seldom noticed in beef, and when they occur are commonly few in number.

According to the latest authorities—Leuckart, Cobbold, Stein, and others—the beef tape-worm is the most common of the cestodes which infest man. Until within about thirty years it was generally not distinguished from the pork tape-worm, and this was accordingly regarded as the most common human species. Since the writer distinctly recognized the beef tape-worm within the last twenty years, all the specimens of Tæniæ, from people of Philadelphia and its vicinity, that have been submitted to him for examination—perhaps in all about fifty—have appeared to belong solely to Tænia saginata. The prevalence of this species with us is no doubt due to the common custom of eating underdone or too rare beef, while the pork tape-worm is comparatively rare, as with us pork is only used in a well-cooked condition.

TÆNIA SOLIUM.—SYNONYMS: The Pork tape-worm; Solitary tape-worm; Armed tape-worm.

Larval condition: Cysticercus cellulosæ; Pork measle-worm.

Until a recent period this species was generally regarded as the most common tape-worm of man—a view which in great measure was due to the circumstance that the beef tape-worm was not distinguished from it. It was called the solitary tape-worm, still expressed by the specific name, from the impression that it rarely occurred otherwise than single at a time in a person. This has also proved to be incorrect, likewise due to the two kinds of tape-worms having been confounded together; for while the beef tape-worm most commonly occurs solitary, the pork tape-worm not unfrequently occurs with several together.

The species is now appropriately named the pork tape-worm, as indicating its common source—pork used as food. The frequency of the parasite is proportioned to the prevalence of the custom of using pork in a raw or imperfectly cooked state, conjoined with that of depositing excrement where it may be accessible to hogs. In the mature condition the pork tape-worm is peculiar to man and lives in the small intestine, but in the larval condition, though especially infesting the hog, it also occasionally infests man, and lives in any organs of the body, but mostly the muscles, liver, and lungs.

The mature pork tape-worm, as commonly seen, is a soft white, thin, band-like worm, from five to ten feet long and about four lines where widest. The head is spheroid, about the size of that of an ordinary pin, and smaller than that of the beef tape-worm. It is furnished with four hemispherical cup-like suckers, and the summit forms a blunt papilla armed with a double circle of twenty-five or twenty-six hooks. The neck is narrow, thread-like, about an inch long, and merges into the segmented body, which gradually widens to the extent mentioned. The segments, at first much wider than long, as they successively enlarge also become more distinct and proportionately longer, so that the more posterior ripe ones are as long as they are wide, and often longer, though not to the same degree as in the beef tape-worm. The genital papilla, with its external aperture, is marginal as in the latter. The fully-developed uterus is quite distinctive in character from that of the beef tape-worm. The median tube is coarser, and the lateral branches are likewise coarser, much fewer—half the number or fewer—less branched, and less crowded. The ripe and often spontaneously detached segments are commonly longer than broad, more or less elliptical in outline, with truncated ends, and usually measure about half an inch in length by about a third in breadth. The ripe eggs resemble those of the beef tape-worm, but are usually spheroid in shape.

The common source of the pork tape-worm is pork affected with measles eaten in the raw or insufficiently cooked state. The hog becomes affected with measles when it has access to human excrement containing eggs and ripe segments of the tape-worm, which it eats with avidity. The eggs, with their already developed embryos, when swallowed, undergo the same series of transformations and course as those indicated in the account of the beef tape-worm. Pork affected with measles is much more common than beef affected in the same way, and is frequently a subject of ordinary observation. From the difference in habit of the hog and ox this is what might have been suspected; and the fact that the beef tape-worm is more common than the pork tape-worm is to be explained from the circumstance that fresh beef is in more general use than pork, and is usually employed less thoroughly cooked.

The pork measles are commonly seen as round or oval, hard, whitish bodies, from the size of a hempseed to that of a pea, imbedded in the connective tissue of the muscles or flesh. The measle consists of a sac of connective tissue enclosing the scolex or larval tape-worm, which resembles that of the beef tape-worm, but differs especially in the possession of a double circlet of hooks to the head, as in the adult worm. The scolex has long been known, and was regarded as a distinct parasite, with the name of Cysticercus cellulosæ. When fresh pork measles are swallowed by man they are digested in the stomach, and the cysticercus or scolex is released and passes into the small intestine. Here, attaching itself to the mucous membrane by means of its suckers and crown of hooks, it rapidly develops and grows into the adult tape-worm. In this condition it lies in loose folds along the intestine, to which it clings so tenaciously that commonly the neck gives way when the greater part of the worm is forcibly detached by the use of medicines. Fragments, consisting of the more mature segments, frequently appear detached from the posterior part of the worm, and the fully-ripe segments may be seen scattered singly in the course of the large intestine. The isolated segments are thinner and more translucent than those of the beef tape-worm, and in this condition are discharged with the feces, but may also spontaneously creep from the anus, though seldom as compared with the other species.

Experiments repeatedly made by swallowing pork measles prove that the mature tape-worm may be developed in the course of three months. The length of life attained by it under favorable circumstances is uncertain, but it probably continues a dozen years or more.

The scolex of the pork tape-worm, or the cysticercus, so common in the hog, is also less frequently a parasite of man, and in this condition is a more potent agent of danger than in its ordinary or mature state. The infection is due to the introduction of eggs or mature segments of the tape-worm into the stomach—a circumstance which may readily occur through handling these objects and transferring them to the mouth, or more rarely perhaps by their transference from the intestine into the stomach through vomiting.

In the measle form the parasite may occur in any organ of the body, but is mostly found in the muscles and subcutaneous tissue. Its pathological significance depends on its number and position. Located in the nerve-centres, it may occasion the most serious consequences. Usually it occurs in small numbers and gives rise to no obvious inconvenience, and is only accidentally detected in dissection after death. It appears to maintain its vitality for some years, but finally dies, and undergoes degradation. Only when it can be detected in such position as the interior of the eye or beneath the conjunctiva can the patient be relieved by surgical aid. Elsewhere, even if its presence is suspected, it is ordinarily beyond the reach of medical treatment. The writer a few years since, in dissecting the body of a colored man to illustrate his lectures on the muscles, found two living measles, of which one was in the diaphragm and the other in the transversalis muscle of the abdomen, but none were detected elsewhere. The parasite unquestionably gave no inconvenience to its host during life.

Other species of Tænia which have been observed as parasitic in the human intestine are mostly of rare occurrence.

TÆNIA CUCUMERINA, the common tape-worm of the dog, and TÆNIA ELLIPTICA, the common tape-worm of the cat, are very much alike in appearance, and are regarded by many authorities as the same species. They occur frequently in considerable numbers in these animals, living in the small intestine. They have also been occasionally found in man, especially children.

It is a comparatively delicate worm, chain-like in appearance, ranging from four inches to a foot in length. The head is provided with four suckers and a prominent rostellum armed with about sixty hooks. The neck and anterior part of the body are thread-like. The mature segments are elliptical in outline or like a melon-seed, whence the name. There is a double set of sexual organs, and a genital orifice occupies the middle of both lateral margins of the segments. The ripe segments become readily detached and creep actively in the intestine, and are either expelled with the feces or they spontaneously creep from the anus. The eggs are comparatively few and measure 0.05 mm.

Late researches appear to show that the eggs adhering to the hair about the anus or elsewhere are eaten by lice of the same animals, and within these insects undergo further development. The dog and cat, subsequently swallowing the lice, infect themselves with the mature worms. Thus also persons, especially children, from too great familiarity with these animals, directly or through their food, may likewise become infected.

TÆNIA NANA, the Dwarf tape-worm, has been observed but once. It was discovered by Bilharz, in Egypt, in a boy who died of meningitis. It is a little worm, about half an inch in length, and occurred in large numbers in the duodenum.

TÆNIA TENELLA.—This is another small species, which has been but once observed. It is described by Cobbold, who suspects it to be derived from measles of the sheep.

TÆNIA FLAVOPUNCTATA is also a small species, from eight to ten inches long, with ripe joints about one millimeter long and from one and a half to two millimeters broad. It is described by Weinland, and has also been but once observed. A half-dozen specimens were discharged from a healthy child, of nineteen months, in Boston, Mass.

Since the above was written the author has had the opportunity of examining some little tape-worms which he suspects to be of the same kind as the former. They occurred in the practice of T. V. Crandall in Philadelphia, and were expelled from a child of three years of age after the use of santonin. About a dozen fragments appear to have pertained to three worms, from twelve to fifteen inches in length. The head in all was lost. The anterior part of the body is thread-like, the posterior part about two and a quarter millimeters wide. The width of the joints is more than twice the length. The ripe joints are pale brown, and are remarkable for the comparative simplicity of the uterus, which is distended with brown eggs. A peculiarity of the worm is the repeated but irregular alternation of fertile with sterile joints.

Amer. Journ. of Medical Sciences, 1884, p. 110.

The species is probably more common than might be supposed, and from its small size, and perhaps harmless character, has generally escaped notice.

TÆNIA MADAGASCARIENSIS.—This species, described by Davaine, is imperfectly known. Fragments of the worm have been twice observed in the Comoro Islands.

BOTHRIOCEPHALUS LATUS.—SYNONYMS: Dibothrium latum; Tænia lata; Broad tape-worm.

This tape-worm, of another genus than the preceding, is a common parasite of man in certain localities of Europe, but has not been found as an indigenous product elsewhere. It occurs especially in Sweden and Russia, East Prussia, Poland, and West Switzerland. In the latter country it prevails to such an extent that it is reported that about one-fourth of the inhabitants of Geneva are thus infested. Among the tape-worms submitted to the writer from time to time for identification a few years ago was a large specimen of Bothriocephalus latus, but it proved to have been derived from a Swede who had arrived in this country only a few months previously.

There are many species of Bothriocephalus, which in the adult condition mainly live in fishes. The genus is distinguished from Tænia by many points, chiefly in the form and construction of the head, the form of the joints and uterus, and the position of the genital aperture, which is situated centrally on one of the broad surfaces instead of the lateral margin.

The broad tape-worm is the largest of the tape-worms infesting man, a full-grown specimen reaching to twenty-five feet in length with a breadth of three-fourths of an inch, and consisting of upward of four thousand segments. It is a soft, grayish, flat, band-like worm, with head, neck, and segmented body holding the same proportions as in the other tape-worms. The head is elongated, clavate, and is provided with a long, narrow, elliptical sucker on each side. The narrower neck is short and merges into the segmented body, which gradually widens to half an inch or more. As the segments successively enlarge, they increase proportionately to a greater extent in breadth, so that their width for the most part measures from two to four times their length. A few toward the end of the series become narrower and longer than those in advance. In the ripe segments the uterus, distended with brownish eggs, forms a central rosette-like group of pouches. The genital aperture is central in the broad surface of the segments, and is always on the same or ventral side.

The broad tape-worm inhabits the small intestine, and is usually found single, but occasionally several together, and sometimes also in association with one or both the other common tape-worms. The species is also reported to be not infrequent in the dog.

Ripe portions of the broad tape-worm become detached in fragments of variable length, to be discharged with the feces. The partially-emptied appearance of the uteri in these fragments indicates the laying of the eggs previous to the expulsion of the latter. The eggs are oval, of a light-brown color, and measure about 0.07 mm. long. The shell at one pole is furnished with an operculum or lid for the escape of the embryo. This is developed subsequently to the discharge of the eggs from the intestine. If the eggs are placed in water, in the course of some months the embryos are developed and escape from the shell. The embryo is a round or oval body furnished with three pairs of spicules, as in that of the Tæniæ, but differs in possessing a ciliated envelope, by means of which it freely swims about in the water. After some days the embryo discards its envelope and creeps about in an amoeboid manner. Further than this, until recently, the fate of the embryo was unknown. Braun of St. Petersburg, after determining the presence of scolices of Bothriocephalus in the muscles, liver, and organs of generation of the pike, trout, and eel-pout, by feeding these to cats and dogs succeeded in rearing worms which differed in no respect, except in being smaller, from the Bothriocephalus latus of man. Such being the case, it becomes evident that man may ordinarily become infested with the parasite by eating raw or insufficiently cooked fishes of the kind mentioned.

BOTHRIOCEPHALUS CORDATUS, described by Leuckart as a common species infesting the dog in Greenland, has been reported as having once been found in a woman. Böttger regards it as not distinct from Bothriocephalus latus.

BOTHRIOCEPHALUS CRISTATUS.—This species, but once observed, is described by Davaine. It was passed by a child in Paris, and the worm was upward of nine feet in length.

SYMPTOMS OF TAPE-WORMS.—Whichever may be the species of tape-worm infesting the human intestine, the symptoms to which it gives rise are mainly of the same character, modified of course in degree by the size and number of the parasites and the susceptibilities of the patient. Clinging by means of the head to the mucous membrane of the intestine, and involved among the valvulæ conniventes and villi, the worm may extend in loose folds along the greater part of the course of the intestine or lie coiled in an elongate mass. Besides being rendered evident from time to time by the discharge of segments or fragments, the beef tape-worm especially sometimes introduces itself to the notice of its host through the segments creeping from the anus. Sometimes segments of tape-worms are vomited, especially in women; and the exhibition in this way, especially of the pork tape-worm, is to be deplored, for should segments be retained in the stomach the patient becomes further liable to be affected with measles or cysticerci.

Some persons continue infested with a tape-worm a long time without suspecting its existence and with little or no inconvenience, and perhaps first become aware of its presence by the accidental discovery of segments discharged from the bowels. Usually, however, the parasite creates more or less disturbance, and not unfrequently occasions great discomfort. The symptoms are both local and of a general nature. Itching at the extremities of the alimentary canal and various dyspeptic symptoms are common; uncomfortable sensations in the abdomen, uneasiness, fulness or emptiness, feeling of movement attributed to the worm, and colicky pains; disordered appetite, sometimes deficient, oftener craving; paleness, discoloration around the eyes, furred tongue, fetid breath, and sometimes emaciation; fulness of the forehead, dull headache, buzzing in the ears, twitching of the face, and dizziness; often uncomfortable feelings in the abdomen increased by fasting, which are temporarily relieved by taking a full meal. Certain kinds of food also at times appear to produce greater uneasiness, apparently due to more than usual disturbance of the parasite. Symptoms of a more grave character are sensations of fainting, chorea, and epileptic fits. Others of a chlorotic and hysterical character are not unfrequent, especially in women, who also may suffer more or less from uterine disorder.

All the ordinary symptoms are quickly relieved by the expulsion of the tape-worm—permanently if it is entirely removed, but temporarily, as is frequently the case, when only the greater bulk of the parasite is discharged and the head continues to remain securely attached to the intestine and ready to renew its many-segmented body. The tape-worms are capable of a wonderful amount of extension from traction without detachment; and from the delicacy of the neck and the anterior part of the body, and the action of medicine on the peristaltic motion of the intestine, the posterior part of the worm, including its great bulk, is most apt to be torn away and discharged, while the head remains. So long as this is the case, and the worm has not been poisoned or killed, the anterior portion grows, and thus the parasite is renewed and accompanied by a return of all the former symptoms. Under the appropriate treatment the evacuations of the patient should be carefully inspected, so as to satisfy both physician and patient that the parasite has been completely expelled. To properly examine the evacuations, they should be repeatedly drenched with clear water, and the sediment, after the settling of the washings, must be inspected. It is only when the physician has seen the head of the parasite that he can reasonably ensure his patient a permanent cure.

TREATMENT.—To get rid of tape-worms many remedies have been employed, though comparatively few retain a reputation for positive success. Some act by powerfully operating on both bowels and worms, producing the detachment and discharge of the latter without killing them, as is often indicated in the lively movements they exhibit after their expulsion. Others poison and kill the worms, and also cause their detachment and expulsion from the bowel.

Before the administration of the appropriate medicine for tape-worms, with the object of rendering it more effective it is advisable to bring the alimentary canal into a condition which will render the parasites most vulnerable. For this purpose fasting is to be recommended for several days previously, and when food is used it should be in moderate quantity, and of such a character as to leave little residue to accumulate in the intestine. Wheat bread, the ordinary meats, milk and coffee, are best, while the usual vegetables should be avoided.

One of the most effective remedies is the oil of turpentine in the dose of one or two fluidounces, made into an emulsion with white of egg and sugar; children require about half the quantity. The large dose is less apt to produce the usual objectionable effects of that medicine than small ones. The only inconvenience caused by it is the heat of the stomach, some febrile excitement, and fulness of the head or headache lasting for one or two days. The effects are more apt to occur when the medicine does not act as a cathartic. The oil usually operates quickly, killing the worm and producing its discharge. If it does not act in the course of two or three hours, a full dose of castor oil may be given, and, if necessary to aid the action of this, enemata may be employed. To ensure the purgative action of the oil of turpentine it may be advantageously associated with the castor oil, of each a fluidounce made into an emulsion.

Another and effective remedy is the root of the male fern, Aspidium filix-mas, used in decoction or electuary. Stein of Frankfort recommends the ethereal extract as the best preparation, and prescribes it in doses of from seven to ten grammes, enclosed in half the number of gelatin capsules and administered at short intervals within half an hour. It should be taken in the morning fasting, after taking a cup of coffee, swallowing the capsules with the aid of a second cup. Half an hour after the capsules are taken a mixture of castor oil, brandy, and ginger syrup, of each fifteen grammes, should be administered. The treatment has proved all that could be desired, and the worm, including the head, is discharged altogether, rolled into a ball.

The bark of the pomegranate-root, Punica granatum, is also a powerful and efficient remedy, but often proves very disagreeable from its producing violent pains in the abdomen, with nausea and vomiting. It also generally purges, occasioning the discharge of the worm. Küchenmeister prefers it to any other medicine, given in the form of decoction prepared by macerating three ounces of the fresh bark in twelve fluidounces of water for twelve hours, and concentrating the infusion by gentle heat to one-half. He recommends it to be taken after fasting a day and the administration at night of two fluidounces of castor oil. It is to be given in three or four doses within an hour. Should the medicine not purge, it should be followed by another dose of castor oil.

Recently, Feraud has recommended the tannate of pelletierin, the alkaloid of which is derived from the pomegranate-root, as the most powerful of remedies for tape-worm, the dose for an adult being one-half to three-fourths of a grain. The patient should fast a day on bread and milk, and the following morning, before rising, take an infusion of one-third of an ounce of senna. This should be followed an hour later by half the medicine diffused in a little water, and the patient should remain quiet in bed to avoid nausea and vomiting. Half an hour later the rest of the medicine is to be given, followed in another half hour by a dose of castor oil. Should there be no stool after an hour, purgative enemata may be used. In one case twelve beef tape-worms were discharged together measuring, collectively, fifty meters.

Kousso, the flower of Brayera anthelmintica, an Abyssinian herb, has been of late much employed as a remedy for tape-worms, but with many physicians of experience it has lost favor. Heller speaks of it highly, and recommends it to be taken in the morning, an hour after the patient has taken coffee. The dose is from half an ounce to an ounce, and is conveniently taken in compressed balls or disks, coated with gelatin, and swallowed at intervals in the course of an hour, aided by mouthfuls of coffee. Any disposition to vomit should be repressed, which is rendered easier by taking small mouthfuls of strong coffee or pieces of ice.

Koussin, an alcoholic preparation of kousso, is also efficient, and has the advantage over the latter that it does not occasion nausea. It has been used in the medical clinic of Munich in the dose of 30 grains, and it has been a very rare occurrence that the result was not all that could be desired.

The seeds of the common pumpkin, Cucurbita pepo, are extolled by many physicians as a remedy for tape-worms; and the writer has twice had the opportunity of observing large specimens of the beef tape-worm which were expelled after the administration of this medicine. The dose is an ounce of the seeds bruised into a paste and made into an emulsion. It should be taken in the morning, fasting, and followed in an hour or two with a full dose of castor oil.

Santonin, a principle derived from santonica, Artemisia maritima, is reported as a remedy for tape-worms, but its efficacy has also been denied. The dose is from two to four grains for an adult, and from one-quarter to one-half a grain for children over two years. It is best administered in lozenges prepared with sugar and tragacanth.

The quinia sulphate has also been recommended as an effectual remedy both in tape- and seat-worms.

As regards the prophylaxis of tape-worms, there are some important points to which we direct attention.

The evacuations of patients containing tape-worms, their segments and eggs, should not be carelessly thrown away, at least in places accessible to animals which may become infected. They should be treated with boiling water, the heat of which is sufficient to kill all animal parasites. The handling of living tape-worms and segments should be avoided, as eggs which may adhere to the hands, if transferred to the mouth and swallowed, will produce infection.

Meats visibly infested with measles are not fit and should not be used as food. Raw meat should altogether be discarded as food, both for the sick and well, and all meats should be thoroughly cooked. As a rule, meat should not be used so long as it appears red or on cutting emits a bloody liquid. A large piece of meat requires long boiling or roasting for sufficient heat to penetrate to the interior to destroy any parasites that may be present. Even salted meats and hams should be cooked to ensure against parasitic infection. It is important also to avoid food prepared by uncleanly persons who may be infested with tape-worms.

As regards our domestic animals, which are the common source of the infection of man with tape-worms, they should also be protected from infection as far as possible. This is to be done by preventing them from having access to human excrement. As Heller remarks, with this object the barbarous custom of defecating in every place promiscuously should be put down with a high hand.

Several years since a physician of Texas sent to the writer a piece of pork, making inquiry as to its condition, and stating that all the pigs of his vicinity were diseased and their flesh similarly affected. It contained a number of measles or larval tape-worms. On giving the information and the probable cause of the affection of the pigs, the doctor reported in return that there was not a privy in his village. Until our people are more careful with the raising of pigs, European governments will have reason for prohibiting the importation of our pork.

TÆNIA ECHINOCOCCUS.—SYNONYM: Hydatid tape-worm.

Larval condition: Echinococcus; E. hominis; E. veterinorum; E. granulosis; E. scolicipariens; E. altricipariens; E. hydatidosus; E. multilocularis; E. cyst; Hydatid; Hydatid cyst; Acephalocyst.

This tape-worm, in its mature state the most insignificant looking of its kind, though not strictly an intestinal worm of man, in the juvenile condition is one of his most dangerous parasites, as being the source of hydatid tumors. The adult tape-worm lives in the small intestine of the dog and wolf, in some localities often existing in these animals in thousands together. From its diminutive size it may be readily overlooked, concealed or obscured by the villi among which it is suspended to the mucous membrane. It is about a fourth of an inch in length, and consists of but four segments, of which the last alone exhibits the ripe condition. The head resembles in construction that of the pork tape-worm, being provided with four suckers and a prominent crown, with from thirty to fifty hooks arranged in a double circle. The terminal ripe segment exceeds in size all the preceding together, and before it separates from the series another is ready to take its place. The ripe eggs contain the usual six-spined embryo as in other tape-worms.

The mature worm is remarkable for the comparative shortness of its life, which, according to Siebold, is about seven weeks. Apparently to compensate for the small number of its segments, the larval form is endowed with the power of multiplying itself to a wonderful degree.

It is only in the larval condition that the hydatid tape-worm infests man, and in this state also it infests the ape, the ox and sheep and other ruminants, also the horse, hog, and indeed many other animals of the same class.

If the eggs of the tape-worm are swallowed, which may readily happen by too free intimacy or association with infested dogs, the liberated embryos obtain access to the intestine. Penetrating the mucous membrane, the embryos thence may migrate to any part of the body. From the comparative frequency of hydatid tumors in the liver we may suspect they mostly enter the portal venous system and take the course of the blood-current. It is, however, probable that they migrate directly to their destination, for hydatid tumors are also frequently seated in the neighboring organs and the abdominal walls. The embryo tape-worm, once fixed in position, becomes the starting-point of a hydatid tumor.

When dogs are fed on the liver, or other parts affected with hydatid tumors, from the sheep or other animals, the scolices are liberated, and, passing into the small intestine, are there developed into the mature tape-worms.

Hydatid tumors occur in any of the organs of the body, but are more frequent in the liver than in all others together. They are common in the lungs, kidneys, spleen, omentum, and subperitoneal tissue of the abdominal walls. They are less common in the heart, brain, spinal canal, the pelvic viscera, and the bones. Mostly but a single tumor is found in the same person, but occasionally several occur together in the same or in different organs.

There are several varieties of the hydatid tumor. In man the more common form consists of a cyst or a group of cysts enclosed in a connective-tissue envelope induced by the presence of the parasite. The simple cyst is produced through the transformation of the echinococcus embryo, and the group of cysts is derived from the former by proliferation; and hence the first has been called the parent cyst, and the others the daughter cysts. These also in the same manner may produce a third series, called granddaughter cysts. The parent cyst, at first spherical, becomes modified in shape according to the space it occupies and the resistance to which it is subjected, thus assuming an oval, lobulated, or other form. It may increase in size to that of a cocoanut or larger, and may remain simple, but usually is compounded by proliferation in the production of daughter cysts. These may be few or many up to hundreds, and range from a minute size up to that of a walnut, and are spherical or modified in shape by mutual pressure or other cause. The cysts are filled with a clear watery liquid of saline taste, but without albumen.

The hydatid cysts are usually composed of an outer thick, translucent, homogeneous, laminated, glistening, highly elastic membrane, the ectocyst, and an inner thin, granular, and cellular layer, the endocyst. From the endocyst originate minute buds, which become the brood-capsules of the larval worms or scolices. These form little groups of a few to a dozen individuals suspended within the brood-capsules, but capable of eversion from them. The individual scolices, which appear to the naked eye as mere white points, have the form and construction of the head-segment of the mature Tænia echinococcus. After death or by violence they become easily detached, and then float free in the liquid containing them. In some cases the echinococcus cysts develop no scolices, in which condition they constitute acephalocysts. Occasionally the echinococcus embryo undergoes imperfect development, constituting the multilocular hydatid tumor, rarely found elsewhere than in the liver.

Echinococcal tumors, especially those which have many daughter cysts, when accessible are remarkable for exhibiting a tremulous movement when grasped by the hand and quickly tapped with the finger.

Infection through the embryonic form of the Tænia echinococcus, as the source of hydatid tumors, is productive of the most disastrous consequences, and has ended in the destruction of many lives both of men and domestic animals. The parasite is not directly productive of suffering, but its effects and dangers are proportioned to the size of the tumor it occasions and the character and importance to life of the organ in which the latter is situated. With the increase of the hydatid tumor, usually of very slow growth, it encroaches upon the surrounding parts, and if these are not displaced they become disorganized and atrophied.

The liability and frequency of infection with the hydatid disease appear to be proportioned to the prevalence of intimate association with the dog. In Iceland, in which it is said every peasant owns half a dozen dogs, which share his dwelling with him, it is also reported that one-sixth of all the deaths are due to the hydatid parasite.

Ordinarily, the hydatid disease is beyond the reach of medical treatment. The mercurials and potassium iodide have been recommended, but the results are very doubtful. Apparently as an indication how little hydatid parasites may be influenced by medicine, the following incident will show: The writer once received for dissection the body of an English sailor which had been injected with zinc chloride for preservation. In the abdominal wall in the right iliac region there was a hydatid tumor the size of a fist. On examination of the tumor it was found full of daughter cysts, and these contained living scolices, though the man had been dead several days and the tissues were bleached by the zinc solution.

Favorable results in the treatment of hydatid tumors are only to be expected through surgical means when they are accessible.

As a prophylactic measure against infection the avoidance of too intimate association with dogs is especially to be recommended.

In concluding the chapter on Tænia echinococcus, as a prophylactic against this and other parasites Cobbold gives the advice that "all entozoa which are not preserved for scientific investigation or experiment should be destroyed by fire when practicable, and under no circumstances whatever should they be thrown aside as harmless refuse."

TÆNIA ACANTHOTRIAS.

Larval condition: Cysticercus acanthotrias.

This species has been but once observed, and only in the larval condition or that of the scolex, which was first described by Weinland. About a dozen specimens were found by Jefferies Wyman of Boston in the body of a woman of Virginia who died of phthisis. They were situated in the connective tissue beneath the skin and in the muscles, except one, which was attached to the dura mater. The scolex is distinguishable from that of the other human tape-worms in possessing a triple circle of hooks. The mature form of the worm remains unknown.