Tænia solium, Linneus.—This cestode was formerly known as the common tapeworm, but in England it is of far less frequent occurrence than the beef tapeworm. In contradistinction it is best to speak of it as the pork tapeworm. Though only one specimen is usually present, the bearer may entertain several worms of this species at one and the same time. The parasite has been known to science from the earliest times, though possibly not earlier than the measles, or Cysticerci, from which it originates. Hippocrates, Pliny, and Aristotle describe the full-grown worm; and, in regard to the larvæ, some have gone so far as to express their belief that the prohibition of swine’s flesh as food amongst the Jews and other Oriental people, was dictated by sanitary considerations. Weinland has suggested that the Mosaic commandment not to eat pork may have originated in an old popular notion “of the fact that tapeworm sometimes comes from this food.” Weinland’s hypothesis is probably correct, for if one supposes Moses to have been supernaturally informed that pork would produce tapeworm disease, one naturally asks why veal and beef should not also have been prohibited, seeing that these meats also frequently harbour tapeworm larvæ.

A perfect pork tapeworm presents itself to the eye of the observer as a long, soft, white, jointed strobile, which, when alive, elongates and contracts itself with facility. Though commonly spoken of as a single creature, it is a compound of many individuals. These are variously called “cucurbitini,” “zooids,” “proglottides,” “segments,” “links,” or “joints.” When fully grown the segments are capable of detaching themselves and of enjoying a free and independent existence. Very annoying it is to the human bearer to be continually reminded of his unwelcome “guests” as they seek to quit his interior.

The head of Tænia solium is seldom seen in anatomical museums, although the evacuation of pork tapeworms is not of rare occurrence. Placed under the microscope, the head displays a quantity of dark, almost black, pigment granules, which are abundant at the base of the rostellum and in the neighbourhood of the hook-fangs. They are equally present and abundant in the pork measle proper, and in measles derived from the human subject. The cephalic hooks of this cestode are comparatively large, those of the greater circle individually measuring 1/156″, whilst the smaller hooks have a length of about 1/220″.

The male reproductive organ consists of a number of small vesicles or sacs, in which filiform spermatozoa have been detected, these latter, when ripe, being conducted by a vas deferens into a seminal pouch, from which a canal passes laterally into the penis; the latter organ, in its retracted condition, being lodged within a flask-shaped sheath or cirrhus-pouch. The female organs are somewhat more complicated. They consist of two masses of vitelligene glands occupying a limited space, a small ovarium, a centrally-placed and largely-developed branched uterus, canals of outlet leading from all these organs, and enlargements of the main passages to form internal seminal reservoirs; also, a vaginal canal, which is widened at its termination to form a receptaculum for the curved penis.

In addition to the above-named structures, the entire series of joints from the head downwards are traversed by a set of vascular canals, which are doubled in the region of the head. These form the so-called aquiferous system. There are two main channels, one passing down on either side of the worm, both being connected by transverse vessels, which occur singly at one end of every joint.

The eggs in their mature condition are globular, and contain a six-hooked embryo. They present an average diameter of 1/694 of an inch, the shell itself measuring about 1/4000″ in thickness. In 1856 I observed that many of the eggs, whilst still within the uterine branches, displayed an outer envelope, very delicate in structure and totally dissimilar from the egg-shell proper. This has since been more accurately described by Weinland, Van Beneden, and Leuckart. The outer membrane, according to the last-named authority, constitutes the primitive yolk-membrane, within which a part of the yolk-contents separates to form the true egg and embryo by a process of daughter-cell formation. The remaining part of the yolk forms a granular mass, being probably concerned in the formation of the true chitinous shell. The true shell displays a series of radiating and circular lines; the former, however, are more conspicuous than the latter, being due, according to Leuckart, to the presence of a series of fine rod-like chitinous elements, which are formed on the external surface of the original true shell-membrane. The enclosed embryo is furnished with six boring spines, arranged in three pairs, its granular body being invested by an extremely delicate skin-membrane, which is separated from the inner surface of the shell by a clear transparent fluid. The embryo measures 1/1250″ in diameter.

The scolex or higher larval stage of growth forms the well-known pork measle or Cysticercus (telæ) cellulosæ of authors. The smallest measles found by Leuckart measured 1/25″ in length. They were obtained from the brain, liver, and intermuscular substance of a pig fed with proglottides about thirty days previously. Only those specimens, however, occurring in the liver at this early period displayed an outer membrane proper to the worm itself, the others being simply invested with capsules formed out of the connective tissues of the host. Many measle-masses in the same host were much larger, presenting an average diameter of 1/6″. The smallest already displayed a smooth, transparent, homogeneous, outer, cuticular membrane, overlying a double, finely-granular corium, the latter being traversed by a branched system of aquiferous vessels. These vessels proceed from a central spot, which marks the position of the so-called head-cone, or receptaculum capitis. It is, in fact, the first well-marked indication of that flask-shaped capsule within which the head, neck, and body of the Cysticercus is formed, and which Goeze long ago very aptly compared to a lantern. As growth proceeds, a central granular mass forms the true foundation of the head, its upper or stalk-like extension becoming the future neck and body. Further changes result in the evolution of the internal water-vascular system, the calcareous corpuscles, the marginal transverse foldings of the body, the four suckers, the rostellum, and, in particular, the double coronet of hooks. All these metamorphoses were minutely followed and described by Leuckart, who found the development of the larva to be completed within the space of ten weeks.

As regards the injurious effects of this parasite upon man, it may be said to act prejudicially in three separate ways. I have remarked in my ‘Entozoa,’ that this parasite may cause disease and death both by its action in the larval and adult states. It may likewise injure us by rendering the flesh of swine unwholesome.

When one or more sexually-mature tapeworms have developed themselves within the human intestine, they are apt to give rise to a variety of unpleasant symptoms, more or less marked according to the habit or irritability of the patient. According to Davaine (p. 103 of his ‘Traité’) the principal features are “vertigo, noises in the ears, impairment of sight, itching of the nose and anus, salivation, dyspepsia and loss of appetite, colic, pains over the epigastrium and in different parts of the abdomen, palpitation, syncope, the sensation of weight in the abdomen, pains and lassitude in the limbs, and emaciation.” In ordinary cases there is always more or less anxiety and restlessness; but in severe cases the sympathetic symptoms are very strongly marked, showing themselves in hysterical fits, chorea, epilepsy, and epileptiform seizures, attended by more or less alarming convulsions.

Amongst some of the more interesting and remarkable cases recorded in our English journals, I may instance that of Mr Hutchings, where a complete cure followed the evacuation of the worm which had produced convulsions. Mr Tuffnell records a case where irritability of the bladder and stricture of the urethra were entirely dependent on tapeworm, as proved by the subsequent recovery. At a meeting of the Pathological Society, in 1853, Dr Winslow mentioned his experience of three or four cases of mania arising from tapeworm; whilst on the same occasion Drs Ryan and Davey each recorded a similar instance. A case has also been previously published by Mr W. Wood. At a meeting of the London Medical Society, held on the 10th of April, 1837, Dr Theophilus Thomson (during an interesting discussion on this subject) stated the facts of a case where the presence of tapeworm had given rise to a tumultuous action of the heart, this symptom entirely disappearing after evacuation of the worm. Our journals likewise (anonymously) record a considerable number of cases from foreign sources. Thus, in the ‘London Medical Gazette’ for 1840, there is the case of a lady, aged thirty-seven, who had convulsions attended with a complete loss of consciousness, the separate fits lasting an hour at a time. The passage of the worms effected a complete cure. In the same journal for 1838, there is also the case of a younger lady (aged twenty-seven) suffering from epilepsy, in whom a complete cure had been similarly brought about; here, however, in addition to a single specimen of the Tænia solium, there were two lumbrici present. This journal also gives Ettmüller’s case, where eighteen tapeworms were the cause of hysteria; and likewise the case published by Steinbeck, where the symptoms presented an altogether peculiar character. More precise references to some of the above cases will be found in the ‘Bibliography’ below; and I may also refer to my published lectures on Helminthology and especially to my separate work on Tapeworms, where particulars of one hundred cases are briefly recorded. These were all average cases occurring to me whilst in private practice. Davaine’s book also abounds with remarkable cases.

Whilst the adult worm is capable of producing serious and even fatal mischief to the bearer, the larvæ or measles much more frequently prove fatal. The Cysticerci may develop themselves in almost any situation in the human body, but they occur most commonly in the subcutaneous, areolar, and intermuscular connective tissue; next, most commonly in the brain and eye, and lastly, in the substance of the heart and other viscera of the trunk.

In my ‘Entozoa’ I have stated that probably not less than one hundred cases have been observed where death had resulted from Cysticerci in the brain. Griesinger alone collected between fifty and sixty such cases. Mental disturbance occasioned by the presence of measles in the brain may occur with or without epilepsy. When Griesinger states that “the epilepsy from Cysticercus is in all respects like cerebral epilepsy and the psychical disturbances have nothing characteristic about them,” he tacitly admits the impossibility of correct diagnosis during life.

Since the publication of Griesinger’s well-known memoir on Cysticerci of the brain, many similar cases have appeared, and amongst the more recent of these is one by Dr Frédet in which the victim was a young man twenty-two years of age. Though apparently in good health he fell dead in the street; the fatal result being due to the presence of a Cysticercus within the pons Varolii.

Many other cases of earlier date are especially noteworthy. Thus Mr Toynbee recorded a case where an hydatid (which I take to have been the Cysticercus cellulosæ) situated in the middle cerebral fossa beneath the dura mater, but in this instance death ensued from other causes. Mr Ottley gives the case of a woman aged forty, where an undoubted Cysticercus in the brain gave rise to distressing fits, convulsions, and death. Then, again, there was Dr Burton’s workhouse patient, only twenty years of age, who was found dead in bed, but who at the time of admission merely complained of pain in the head. After death, four hydatids (Cysticerci) were found in the tuber ancillare at the summit of the spinal marrow. M. Bouvier’s similar case is also reported in our periodicals. Of instances where Cysticerci occupied the cavity of the eye, we have one or two cases by Mackenzie of Glasgow, one by Mr Rose of Swaffham, and others by Windsor, Logan, and Estlin. Amongst the more peculiar cases, I may mention that described by Dr Greenhalgh in the ‘Lancet’ (1848), where the Cysticercus was lodged within the substance of the lip. Five similar cases are likewise recorded by Heller of Stuttgard. Then there is Dupuytren’s case of a Cysticercus ensconced within the great peroneus muscle; and also Fournier’s, where several of these scolices were said to have been found in a boil. The so-called Trachelocampylus, discovered by Frédault in the human brain, was neither more nor less than a common Cysticercus cellulosæ.

It is worthy of remark, as Griesinger has also observed, that in cases where the Cysticerci have taken up their temporary residence in the brain, they are usually found, post mortem, in the grey cortical or peripheral substance of the cerebrum. The particulars of such a case are given in my ‘Entozoa’ where the victim suffered from epileptic fits due to the presence of numerous Cysticerci (fig. 24). The patient was under Mr Hulke’s care.

As regards infection by the adult worm it is not alone sufficient that we avoid underdone meat, as brought to the dinner-table, but we must be especially careful to have our sausages well cooked. Under ordinary circumstances, we are safe for the following reasons:—No respectable butcher will knowingly supply us with pork or with sausages which are measled. Even in the case of underdone meats, in whatever way prepared, it is usually only a small portion which is unaffected by cooking. As we have seen a temperature of 140° Fahr. is sufficient to kill the Cysticerci.

The successful rearing of pork measles by experimentation with the eggs of T. solium has been accomplished by many helminthologists, amongst whom may be particularised Van Beneden, Leuckart, Küchenmeister, Haubner, Gerlach, and Baillet. The converse experiment of rearing the adult worm from the Cysticercus was first successfully undertaken by Küchenmeister on a condemned criminal; Leuckart, Humbert, and others having repeated this method with more or less success.

The dangers arising from infection by swallowing the larval worms or six-hooked embryos are not easily avoided. Our flesh, like pork, thus becomes measled, although certainly not to the spawn-like extent so often seen in the lower animals. A single measle is sufficient to prove fatal; and this humiliating contingency, moreover, is one which we can never be absolutely certain of avoiding. We become the “host” or bearer of the measle by swallowing the fully-developed eggs of the Tænia solium. This we may do directly by handling fresh tapeworms, whose eggs, being concealed under our nails or in our clothing, may subsequently be swallowed, and develop within us accordingly. Even a thorough washing of the hands will not ensure absolute security. In like manner, those who partake of choice salads, prepared from the stores of the market-gardener, run a certain amount of risk. The vegetables may have been manured with night-soil containing myriads of tapeworm eggs, or they may have been watered with fluid filth into which the eggs were accidentally cast. In such cases, one or more tapeworm ova will be transferred to the digestive organs, unless the vegetables have been very carefully cleansed. In the same way, one perceives how fallen fruits, all sorts of edible plants, as well as pond, canal, and even river water procured from the neighbourhood of human habitations, are liable to harbour embryos capable of gaining entrance to the human body. One individual suffering from tapeworm may infect a whole neighbourhood by rendering the swine measly, these animals, in their turn, spreading the disease far and wide. As already remarked, measles sometimes occur in great numbers in different parts of the body. Among the more remarkable cases of the multiple Cysticerci are those recorded by Delore (1864) and Giacomini (1874). In M. Delore’s case, about 2000 were obtained post mortem. Of these, 111 occurred in connection with the nervous centres, eighty-four being in the cerebrum, twenty-two in the membranes of the brain, four in the cerebellum, and one within the substance of the medulla oblongata. Dr Knox published a less notable instance in the ‘Lancet’ (1838); and in the year 1857, Dr Hodges, of Boston, U.S., published a case where the cysts, which in size he compared to rice grains and coffee beans, were felt subcutaneously. The coexistence of Tænia and Cysticerci in the same individual has also recently been observed in France (‘Lond. Med. Rec.,’ 1875). Besides these, several remarkable instances have lately been reported by Davy, Tartivel, and others.

To the literature already quoted in connection with the beef tapeworm the following may be added:

Bibliography (No. 14).—Aran, in ‘Archives Gén. de Médecine,’ 1841.—Baillet, “Helminthes,” art. in ‘Bouley and Reynal’s Dict. Vétérin.,’ tom. viii, 1869.—Bécoulet and Giraud, “On Cysticercus in the Brain,” ‘Bullet. de la Soc. Méd. de Gand,’ 1872; and in ‘Lond. Med. Rec.,’ Feb., 1873.—Birkett, J., Cases, ‘Guy’s Hosp. Rep.,’ 1860.—Bouchut, “Cyst. in the Brain,” ‘Gaz. des Hôp.,’ 1857, and ‘Journ. für Kinderkrankheit.,’ 1859.—Bouvier, ‘Bullet. de l’Acad.,’ 1840.—Burton, in ‘Med. Times and Gaz.’ (supposed hydatids), 1862.—Cobbold, “On Measly Meat and Measles in Man,” the ‘Veterinarian,’ 1876.—Czermack, “Cysticerci causing Insanity,” Corresp.—Blatt, 1838.—Dalton, J. C., “Cyst in the Scrotum,” ‘New York Journ. of Med.,’ 1857.—Davaine (see his ‘Traité’ for many additional references; p. 676).—Davy, R., “Cysticerci in the Muscles,” ‘Rep. of Lond. Med. Soc.,’ ‘Lancet’ for Nov., 1876.—Estling, “Cases of Cysticercus,” ‘Lond. Med. Gaz.,’ 1838–39.—Frédet, “Cysticercus in the pons Varolii,” in the ‘Lancet’ for June 23rd, 1877 (p. 925), from ‘Giornale Veneto de Scienze.’—Fournier, ‘Journ. des Connois. Med. Chir.,’ 1840.—Griesinger, “On Cysticerci of the Brain,” from ‘Med. Jahrb.’ in ‘Med.-Chir. Review,’ 1863.—Harley, J., “Cyst. in the Brain,” ‘Lancet,’ 1867.—Hodges, R. M., “Specimens of Cyst. cell., felt as small tumours just beneath the skin, varying in size from that of a grain of rice to that of a coffee bean,” ‘Rep. of Boston Soc. for Med. Improvement,’ in ‘Brit. Med. and Surg. Journ.,’ 1857.—Hogg, J., “Obs. on Cysticercus,” in his ‘Manual of Ophth. Surgery,’ 3rd edit., 1863.—Holler, A., “Cyst. cell., im Gehirne einer Geisteskranken,” ‘Allgem. Wiener Med. Zeitung,’ 1878.—Logan, R., “Probable Cases of Cyst. cell.,” removed by Robertson, ‘Ed. Med. and Surg. Journ.,’ 1833.—Mackenzie, W., “Cyst in the Eye,” ‘Lancet,’ 1848, ‘Lond. Med. Gaz.,’ 1839.—Mazotti, L., “Caso di numerosi cisticerchi del cervello e delle meningi,” ‘Rivista Clin. di Bologna,’ 1876.—Mégnin, P., “La Ladrerie du porc et le Tænia solium,” ‘La France Médicale,’ 1876.—Putz, H., “Ueber die Lebenszähigkeit des Cysticercus cellulosæ,” &c., ‘Zeitsch. f. pr. Vet.-Wissenschaften,’ 1876.—Rainey, G., “On the Structure, &c., of Cyst. cell.,” ‘Phil. Trans.,’ 1857.—Rizzetti, G., “Rendiconto Statistico dell’ufficio d’igiene di Torino per l’Anno 1873.”—Rudall, J. T., “Cyst. in the Brain,” ‘Australian Med. Journ.,’ 1859.—Tartivel, De A., “Cysticerques multiples dans le tissu cellulaire sous-cutané et dans certain viscères,” ‘Rec. de Méd. Vet.,’ 1876.—Von Gräfe, A., in ‘Arch. für Ophthal.,’ 1857.—Wells, S., Bourman’s Case, ‘Ophth. Hosp. Rep.,’ 1860.—Windsor, J., “Cyst. in the Eye,” ‘Brit. Med. Journ.,’ 1861.

Tænia tenella, Cobbold.—I have long been acquainted with the fact that there is a comparatively small human tapeworm which cannot be referred to either of the foregoing species. In the absence of experimental proof, I incline to the belief that the worm in question owes its existence to measly mutton. The sheep harbours an armed Cysticercus (C. ovis), which I regard as the scolex of Tænia tenella. The specific name (tenella) was originally applied by Pruner to a cestode six feet in length, which he found associated with a larger tapeworm. This latter he called Tænia lata. Whilst Diesing has pronounced Pruner’s Tænia lata to have been a T. mediocanellata, I, on the other hand, consider Pruner’s T. tenella to have been a T. solium. Mr J. C. Mayrhofer has suggested its identity with Bothriocephalus tropicus. When, some years back, I applied the term T. tenella to a new tapeworm (of which I possess several strobiles) I was quite unaware than any similar nomenclature had been adopted by Pruner. From the few facts supplied by Pruner and Diesing, I cannot suppose that our cestodes are identical. Unfortunately my specimens are imperfect, wanting the so-called head. It is not possible to estimate the length of the worm accurately, but the perfect strobile must measure several feet.

On one slide I have mounted nine mature proglottides of a worm which I procured on the 15th Dec., 1875. The segments measure, on the average, exactly 1/10″ in length, and only 1/20″ in breadth. The uterine rosettes are all full of eggs, and their branches so crowded together that I am unable to ascertain their average number. The segments are perfectly uniform in character, their reproductive papillæ alternating irregularly at the margin.

In the autumn of 1872 I caused a lamb to be fed with the proglottides of a tapeworm which I referred to this species. The animal was slaughtered on the 22nd of January, 1873, when the result was stated to have been negative. As I had no opportunity of examining the carcase, I cannot feel quite sure that there actually were no Cysticerci present. On several occasions I have detected measles in the flesh of animals, when none were supposed to be present by those who either assisted me or were professional on-lookers. Assuming my Tænia tenella to be derived from the sheep’s Cysticercus, I think it fitting to describe the mutton measle in this place. Even if T. tenella be not actually the adult representative of the mutton measle (Cyst. ovis), it is quite certain that the scolex in question gives rise to an armed tapeworm, and it is almost equally certain that the adult armed cestode resides in man. In Pruner’s case, which is by no means unique, we have seen that two distinct species of cestode may coexist in the human bearer. It is quite possible that some one may yet have the good fortune to detect the beef tapeworm, the pork tapeworm, and the mutton tapeworm, all together in one and the same host.

On five separate occasions I have detected measles in “joints” of otherwise excellent and healthy mutton brought to my own table, and supplied by the family butcher. On several other occasions I have had these parasites brought under my notice; nevertheless, many persons are either unaware of, or actually deny, the existence of these ovine parasites. Thus, MM. Masse and Pourquier, in the ‘Montpellier Med. Journ.’ for Sept., 1876, make the following statement: “The sheep, not being subject to measles, it seems to us natural to employ the raw meat of that animal whenever it is required for nourishment in the treatment of diarrhœa, in weaning children, in phthisis, and for anæmics.” Clearly, if MM. Masse and Pourquier could have brought themselves to believe that English literature is worth consulting on such matters, they would not have made this statement. Incidentally they also observe, when speaking of beef measles:—“Un fait que nous avons remarqué et que nous tenons à signaler, c’est que nous avons trouvé des cysticerques nageant librement dans l’eau où nous avions plongé de la viande infestée de ladrerie.” Certainly this is a novel experience. That measles should not only get out of their cysts, but should have the power of “swimming freely” in the water is a phenomenon which requires explanation. There must have been some error of observation.

It was in the year 1865 that I discovered the mutton measle (C. ovis, mihi); but I am not prepared to say that the parasite had never been seen before, since it is alleged that a two-headed Cysticercus was obtained by Fromage from the liver of a sheep (as cited by Davaine). Be that as it may, my discovery was announced in a communication made at the Birmingham meeting of the British Association in the autumn of 1865, and subsequently at a meeting of the Pathological Society of London, on the 3rd of April, 1866 (‘Path. Trans.,’ vol. xviii, p. 463). After these dates further announcements and verifications appeared, amongst which I can only refer to my remarks “On Beef, Pork, and Mutton, in relation to Tapeworms,” forming an appendix to the first edition of my work on Tapeworms, 1866; to the “Remarks on Cysticerci from Mutton,” contained in the fourth chapter of the Supplement to my introductory treatise on Entozoa, where a figure of the parasite is given, 1869, p. 27; to Dr Maddox’s paper “On an Entozoon with Ova, found encysted in the Muscles of a Sheep,” recorded in ‘Nature,’ May 15th, 1873, p. 59; to the ‘Monthly Microscopical Journal,’ June, 1873, p. 245; to my further communications in the ‘Lond. Med. Record,’ Aug. 6th, 1873; to my ‘Manual,’ 1874, pp. 74 and 105, Ital. edit. ‘Nota Dell’ Autore,’ p. 133; and especially to the article headed “The Mutton Tapeworm,” contained in the 3rd edit. of my little volume on ‘Tapeworms,’ p. 12, et seq., 1875.

In regard to the measle itself, I spoke of it as smaller than the common pork measle. The head is 1/30″ in breadth, and is armed with a double crown of hooks, twenty-six in all, the larger hooks each measuring 1/160″ in length. The suckers are four in number, each having a breadth of 1/100″. The neck and head are abundantly supplied with calcareous corpuscles, being at the same time marked by transverse rugæ. The data on which I founded my brief description of the scolex were chiefly based on the examination of a specimen which had been procured by Prof. Heisch from the interior of a mutton chop. Subsequently much fuller details of the structure of the scolex were supplied by the illustrated memoir of Dr Maddox (above quoted). This excellent microscopist, however, announced the presence of immature ova within the Cysticerci themselves. As the notion of the existence of eggs in larval cestodes was altogether at variance with what we know of the phenomena of tapeworm life, I suggested that the author might have mistaken the egg-shaped calcareous corpuscles (which I found so abundant in my own specimens) for the ova. In the interests of truth I felt bound to characterise certain of the conclusions arrived at by Dr Maddox as simply incredible, but I regarded his memoir as forming “an important contribution to our knowledge of the structure of the mutton measle.” I had no idea that in pointing to errors of interpretation I should offend the excellent author. However, a long letter appeared in the ‘London Medical Record,’ in which Dr Maddox showed that he was much vexed that I should have “impugned” the “accuracy of his conclusions.” He defended his position with the support of no less an authority than Dr Macdonald, F.R.S., the distinguished Assistant Professor of Naval Hygiène at the Victoria Hospital, Netley. Dr Maddox says:— “We were quite alive to the anomalous position. Hence the exceptionability of the case rests on more than my own evidence.” In regard to this unfortunate dispute I will only add the expression of my conviction that Drs Maddox and Macdonald will eventually become satisfied that no cestode scolex is capable of displaying either mature or immature ova in its interior.

Bibliography (No. 15). Cobbold (l. c., supra), 1865–75.—Idem, “On Measly Meat, &c.,” the ‘Veterinarian,’ Dec., 1876.—Idem, “The Mutton Tapeworm (T. tenella),” No. 16 in my revised list of Entozoa, the ‘Veterinarian,’ Dec., 1874.—Diesing, C. M. (Tænia tenella, Pruner nec Pallas), in “Revis der Cephalocotyleen,” ‘Sitzungsb. der Math.-Mat. Class d. k. Akad. der Wissenschaften,’ Bd. xlix, s. 369, 1864.—Maddox (l. c., supra), 1873.—Mayrhofer, J. C., ‘Die helminth. des Menschen,’ Erlangen, 1854.—Pruner, ‘Krankheiten des Orients,’ s. 245, 1847.

Bibliography (No. 16).—Cobbold, “Parasites of Man,” in the ‘Midland Naturalist,’ April, 1878, p. 98.—Idem, ‘Tapeworms,’ 1st edit., p. 52, 1866; 3rd edit., p. 27, 1875.—Cullingworth (see Bibl. No. 18).—Davaine, ‘Les Cestoïdes,’ l. c., p. 573.—Heller, l. c., s. 594.

Tænia nana, Siebold.—As regards the dwarf tapeworm, unless Spooner’s case be genuine, there is but one solitary instance on record of its occurrence in the human body; moreover, we have no evidence of its having existed in any other host. It was discovered by Dr Bilharz, of Cairo, at the post-mortem examination of a boy who died from inflammation of the cerebral membranes. Prodigious numbers existed. The largest specimen measured only one inch in length. To the naked eye these worms resemble short threads, and consequently they might very readily be overlooked. The head is broad and furnished with a formidable rostellum armed with a crown of hooks. These hooks have large anterior root-processes, which, extending unusually forward, impart to the individual hooks a bifid character. By far the best account of this worm is furnished by Leuckart, to whom I am indebted for a specimen.

Bibliography (No. 17).—Cobbold, ‘Entozoa,’ p. 244.—Davaine (l. c., Bibl. No. 2), p. 574.—Heller, l. c., s. 606.—Küchenmeister, l. c., Eng. edit., p. 141.—Leuckart, l. c., Bd. i, s. 393.—Von Siebold and Bilharz, in Von Sieb. and Köll. Zeitschr., Bd. iv.—Spooner, ‘Amer. Journ. Med. Sci.,’ 1873.—Van Beneden, ‘Iconographie,’ l. c., pl. iii, fig. 17.—Weinland, ‘Diplacanthus nanus,’ l. c., p. 85.

The principal evidence demonstrating the occurrence of the larval representative of this species (Cysticercus tenuicollis) in man, rests upon the two cases recorded in Schleissner’s ‘Nosography’ of Iceland. One of the alleged instances, however, has been proved by Küchenmeister and Krabbe to be that of an echinococcus; so that, after all, there only remains the solitary case observed by Schleissner himself, in which the parasite can fairly be considered as the “slender-necked hydatid.”

To the above, however, may probably be added a specimen preserved in the Anatomical Collection at King’s College, London. It was found connected with an ovarian cyst.

Tænia elliptica, Batsch.—This parasite is readily recognised not merely by its delicate form and small size, but also by the circumstance of its supporting two sets of reproductive organs in each mature joint. Their outlets are situated at the centre of the margin of each segment, one on either side. Ordinarily infesting the cat, this worm is a mere variety of the common Tænia cucumerina of the dog. At all events, from the evidence put forth by Eschricht, seconded by Leuckart, there is every reason for believing that one or other of these closely-allied varieties is liable to infest the human body. It was originally stated by Eschricht that he had received a Tænia canina which had been passed by a negro slave at St Thomas, Antilles. This is a synonym of T. elliptica, which must therefore be very rare in the human body, possibly only occurring in the negro race.

In regard to the source of this parasite, it has been shown by Melnikow that the scolex of Tænia cucumerina resides in the louse of the dog (Trichodectes latus), and thus it is exceedingly probable that the scolex of Tænia elliptica resides in the louse of the cat (Trich. subrostratus). How man becomes infested is not so clear. Melnikow’s paper on the juvenile state of this cestode is contained in the ‘Archiv für Naturgeschichte’ for 1869, and is illustrated by a figure of the measle.

Tænia flavopuncta, Weinland.—Regarded as a new species, the discovery of this little tapeworm is due to the investigations of Weinland. In Dr Jackson’s ‘Catalogue of the Boston Medical Improvement Society’ an account of the contents of a phial is recorded as follows:—“Specimen of Bothriocephalus, three feet in length, and from half a line to one line and a quarter in width, from an infant. The joints are very regular, except at one extremity, where they approach the triangular form, are very delicate, and but slightly connected, as shown in a drawing by Dr Wyman.” It is further stated that the infant was nineteen months old, and that the worm was discharged without medicine, its presence having never been suspected. It was presented by Dr Ezra Palmer in the year 1842. On examining the fragments, Dr Weinland found, instead of a solitary specimen, at least six different tapeworms, all of them being referable to a hitherto undescribed species. There were no heads; nevertheless, it was ascertained that the worms varied from eight to twelve inches in length, the joints or segments being very broad, and at the same time narrowed from above downwards. The parasite was named “the spotted tapeworm,” in consequence of the presence of yellow spots near the middle of the joint. They represent the male organs of reproduction, the outlets of which, as in my T. lophosoma, occur all along one side of the body or strobile. In Weinland’s estimation this parasite forms the type of a new genus which he calls Hymenolepis. A full account of the worm is given in his well-known essay (l. c., Bibl. No. 2).

Tænia abietina and other varieties. I can only notice very briefly certain cestodes which either present malformations or which may be regarded as mere varieties. First in this series is Weinland’s T. abietina. No one who has studied his ‘Beschreibung zweier neuer Tænioiden aus dem Menschen,’ Jena, 1861, can doubt that it is a mere variety of T. mediocanellata. The monstrosity described by him as referable to T. solium must also be referred to the beef tapeworm. The variations in the character of cestode proglottides is practically infinite. A museum might be filled with them. Most common with T. mediocanellata, these varieties more or less prevail with other species. Thus I have seen them in Tæniæ and Bothriocephali alike. I have obtained segments of T. mediocanellata having sexual outlets on both sides of the proglottis, so regularly disposed in a few segments as to suggest the notion of a new species. The coalescence of several segments into one compound segment is frequent, but the most remarkable specimen that I have seen is one contained in the museum of the Royal College of Surgeons. In the old Hunterian catalogue the specimen is described as “two joints of the Tænia solium, with a number of orifices in unequal series on either side.” As stated in the new catalogue of the series, prepared by myself, the “lower segment is furnished with twenty-two sexual orifices, one of which is situated in the central line” on the ventral surface (as in Bothriocephali). References to this and other specimens in the Hunterian Collection will be found below (see Pittard). In regard to Weinland’s conjectural Tænia acanthotrias, based on the circumstance of his having found a Cysticercus that presented three rows of hooks on its rostellum, I need only say that if such a Tænia were found it would only turn out to be a malformed T. solium. The specimens, however, are none the less interesting. Very remarkable and altogether exceptional characters are presented by the strobile of the cestode described by Mr Cullingworth, of Manchester, and of which I possess specimens. Here, apparently, at least two tapeworms are joined together throughout the entire chain of proglottides without intermission. The three margins of each compound segment project at equi-distant angles. Could we have secured the head we should certainly have found six or eight suckers present, since the finest neck-segments showed that the malformation pervaded the entire colony of zooids, sexually mature and otherwise. Mr Cullingworth’s specimen is so remarkable that I subscribe full particulars of the case in his own words. He says:—“A respectable married woman, named Ann H—, forty years of age, residing in Salford, brought to my out-patient room at St Mary’s Hospital, Manchester, on September 3rd, 1873, a few segments of tapeworm as a sample of what she had been passing per anum for about two years. Although never in the habit of taking meat absolutely raw, she told me, on inquiry, that she was particularly fond of tasting it when only partially cooked. The segments were unlike anything I had seen before, and I took them home for examination, ordering the patient meanwhile a draught containing a drachm of the oil of male fern, and giving her strict injunctions to bring to me every fragment that passed away as a result.

“On September 17th she brought me portions of a tapeworm corresponding throughout to the segments I had already seen, and measuring altogether nine feet in length. Unfortunately, the head was not to be found. Along the middle line of every segment in the body a crest or ridge runs longitudinally, and in the centre of the margin of this crest the genital pore is situated. [In 304 segments examined, only four had the genital opening placed laterally. One segment had two openings, viz. one at the lateral margin and the other in the crest.] Underneath the segment there is a longitudinal groove, and the lateral portions are folded together by the apposition of their under surfaces. When hardened in spirit the section of a segment presents a three-branched appearance, the branches being of unequal length, but placed at equal angles. The uterus sends vessels into the crest as well as into the sides of the segment; and the contained ova are exactly like the ova of an ordinary Tænia mediocanellata. Wedged in between, or attached to, the segments here and there, is a stunted and ill-shaped joint, with irregular and unequal sides. A mature joint measures from five eighths of an inch to three quarters of an inch in length, and about half an inch in breadth, and the breadth or depth of the crest is usually one eighth of an inch.

“There are only two specimens that I can find on record at all similar to the one here described, and both of these differ from it in several important particulars. Küchenmeister mentions, as a variety of Tænia mediocanellata, a tapeworm sent to him from the Cape of Good Hope by Dr Rose. This worm possessed a longitudinal ridge, but he describes its mature segments as ‘extremely massive’—more than an inch in length and 3/5″ in breadth. The genital pores, too, were irregularly alternate, and not situated on the crest. On March 20th, 1866, Dr Cobbold exhibited to the Pathological Society of London a specimen of crested tapeworm which was discovered in the museum of Middlesex Hospital, and to which he proposed to give the name Tænia lophosoma (λόφος, crest; σῶμα, body). The reproductive papillæ were all on one side of the chain of segments, a peculiarity which entirely distinguished it from the Cape of Good Hope variety of Küchenmeister. The head of the creature was wanting. It will thus be seen that my specimen does not correspond with either of these in the situation of the genital aperture. Here it is placed in the crest itself, and not unilaterally, as in Dr Cobbold’s specimen, or alternately, as in Küchenmeister’s. It further differs from the Cape variety in the more moderate dimensions of its proglottides. I have adopted, however, the name suggested by Dr Cobbold in the communication referred to, inasmuch as it sufficiently indicates the principal distinguishing feature of the specimen. I may mention that Dr Cobbold saw the specimen during his visit to Manchester, and that he regarded it as a most remarkable and unique abnormality.”

Further, in connection with abnormal cestodes, I may observe that Weinland’s case of a triple-crowned Cysticercus does not stand alone, since a similar specimen is, I believe, in the possession of the Rev. W. Dallinger. This was removed from the human brain. Curious as this subject is, I cannot dwell upon it. Not only are the mature tapeworms and their Cysticerci liable to present monstrosities, but even also their proscolices or six-hooked embryos. Thus, twelve hooks were observed by Salzmann in the embryo of T. elliptica, and Heller also figures two embryos of T. mediocanellata (T. saginata, Gœze) with numerous hooklets. Dujardin saw seven in a Bothriocephalus embryo. Occasionally there have been errors of interpretation made by observers. Thus, Diesing has given beautiful figures of Dibothrium hians in such a way as to suggest different degrees of monstrosity affecting the tail end of the strobile; but this splitting has clearly resulted from injury. Thus also, when I removed five specimens of a new cestode (Diphyllobothrium stemmacephalum) from the intestines of a porpoise, one of them was cleft nearly half way up the strobile. This had been done by the scissors employed in slitting up the gut; but owing to perfect contraction of the incised edges, it was some time before I discovered that the apparent monstrosity had been artificially produced. Lastly, I may add that many of the older writers were well acquainted with larval and other anomalies. Thus Rudolphi described a two-headed Cysticercus from a Lemur, and also a double-headed Tænia crassicollis. This worm had a tripartite body; as had likewise a Tænia crassicollis of which he did not possess the head (corpore prismatico). Other monstrosities were described and figured by Bremser and Creplin. Pallas mentions a two-headed Tricuspidaria (Triænophori nodulosi bicipites), and, as already stated at p. 97, a double-headed Cysticercus has been obtained from the liver of a sheep.

Before quitting the Tæniæ proper, I may observe that several other species have been indicated, based on ovular and other insufficient characters. To these belong Ransom’s supposed tapeworm, and also Weinland’s Tænia megaloön.

Bibliography (No. 18).—Bonnet, C., ‘Œuv. Compl.,’ tom vi, p. 191, 1791.—Bremser, Atlas, by Leblond, Pl. iv.—Chaussat, ‘Comptes Rendus,’ p. 20, 1850.—Cobbold, ‘Catalogue of the specimens of Entozoa in the Museum of the Royal College of Surgeons of England,’ Nos. 118–121, London, 1866.—Idem, ‘Worms,’ l. c., p. 78.—Idem, “On a Cysticercus from the Human Brain,” ‘Brit. Assoc. Rep.,’ 1870.—Creplin, ‘Tænia Monstrum, &c.,’ Berlin, 1839.—Cullingworth, C. J., “Notes on a remarkable specimen of Tapeworm (Tænia lophosoma, Cobbold),” ‘Med. Times and Gaz.,’ Dec., 1873.—Davaine, ‘Les Cestoïdes,’ l. c., p. 570.—Diesing, ‘Zwanzig Arten von Cephalocotyleen,’ figs. 1 and 2, taf. ii (aus dem xii, Bd. d. denkschr. d. Math.-nat. Cl. d. k. Akad.), Wien, 1856.—Dujardin, l. c., p. 619.—Heller, l. c., s. 600.—Küchenmeister, l. c., Eng. edit., p. 139.—Leuckart, l. c., s. 303 and 465.—Levacher, ‘Journ. l’Institut,’ p. 329, 1841.—Pittard, S. R., Remarks in his article “Symmetry,” Todd’s ‘Cyclop.,’ vol. iv, p. 848, 1849–52, in which he refers to a monstrous Bothriocephalus (T. lata) in the Hunterian Museum, old ‘Catalogue of Nat. Hist.,’ pl. iv, p. 50, No. 205; see also my ‘Catalogue,’ l. c., supra, No. 167.—Ransom, in Reynolds’ ‘System of Medicine.’—Rudolphi, ‘Synops.,’ p. 545 and 598–9, with fig. showing the heads of Cystic. Simiæ (biceps), widely apart, 1819.—Weinland (T. megaloön), in Zoolog. Garten, Frankf., 1861, s. 118.—Idem, ‘Essay,’ l. c., p. 11.