Tænia Madagascariensis, Davaine.—This appears to be a well-defined species although the head has not yet been seen. It probably forms the type of a distinct genus. Dr Grenet, stationed at Mayotte (Comores), twice encountered single specimens passed by two young children, eighteen and twenty-four months of age respectively. The proglottides have their genital pores uniserially arranged, and they show, in their interior, remarkable egg-capsules, from 120 to 150 in number in all, each containing from 300 to 400 eggs. These give a long diameter of 1/625″ for the outer envelope and 1/1250″ for the inner, or shell proper. The embryo measures only the 1/2500 of an inch.
A full account of this parasite, with figures, is given by Davaine (‘Les Cestoïdes,’ l. c., Bibl. No. 2, p. 577 et seq.).
Tænia marginata, Batsch.—Although I possess no certain evidence of the occurrence of this parasite in its adult condition in the human bearer, yet there is a tapeworm in the Edinburgh Anatomical Museum referable to this species, which was said to have been obtained from the human body. This worm is very common in the dog.
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.