The organisation of Trichocephalus dispar has been investigated by Dujardin, Mayer, Von Siebold, Eberth, Bastian, and others. Prof. Erasmus Wilson and myself have carefully studied the anatomy of the closely-allied whipworm of ruminants (T. affinis) which is discussed in my ‘Entozoa.’
The statement of Küchenmeister that there are no external appendages in the female Trichocephalus comparable to those known to exist in the allied Trichosomata, is incorrect. Leuckart’s, and especially Virchow’s, researches disproved Küchenmeister’s and Meissner’s notion that Trichinæ were the young of Trichocephalus. The experiments of Davaine render it probable that the young get into the human body in a direct manner. He finds that the eggs undergo no development whilst yet lodged within the host’s intestines. The eggs are expelled per anum in the immature condition in which they first escape from the body of the parent worm. It further appears that, after their expulsion, a period of six months must elapse before embryonic formation commences. The fully-developed embryo measures 1/333″ in length, and resembles the parent to a certain extent.
Whipworms rarely put their bearers to inconvenience; nevertheless, both human and animal hosts occasionally suffer from their presence. Thus, Felix Pascal quotes a remarkable and fatal instance of cerebral symptoms from this cause in a girl of four years of age; and Mr Gibson has recorded an instance in which these worms produced paralysis and loss of speech. According to Professor Axe, sheep suffer severely from the allied species.
Bibliography (No. 22).—Bastian, H. C., “On the Anatomy of the Nematoids,” ‘Phil. Trans.,’ 1866, p. 545.—Bellingham, O. B., “On the frequency of Trichocephalus dispar in the Human Intestines,” ‘Rep. of Brit. Assoc., in Dubl. Journ.,’ 1838, and in ‘Med. Chir. Rev.,’ 1838; see also Bibliog. No. 33 (and the biography of Bellingham by Dr Mapother, in ‘Dubl. Jrn. Med. Sci.,’ 1877, p. 471).—Busk, G., “Anat. of T. dispar,” ‘Ann. Nat. Hist.,’ vol. vii, 1841.—Chiaje, sul Tricocephalo disparo, &c., 1836.—Cobbold, ‘Entozoa,’ pp. 69 and 329.—Idem, ‘Worms,’ pp. 31 and 67.—Davaine, l. c., p. 205.—Idem, ‘Compt. Rend.,’ 1858, p. 1217, and ‘Journ. de Physiol.,’ 1859, p. 296.—Dubini, ‘Entozoografia umana,’ p. 83.—Dujardin, l. c., p. 32.—Eberth, “Die Generationsorgane von T. dispar,” ‘Sieb. und Köll. Zeitschr.,’ 1860, s. 384.—Gibson, D., “On a Case of Paralysis, with loss of speech, from intestinal irritation (produced by T. dispar),” ‘Lancet,’ Aug. 9th, 1862, p. 139.—Goeze, ‘Naturg.,’ s. 112.—Gurlt, ‘Path. Anat.,’ p. 350.—Küchenmeister, l. c., s. 235; Eng. edit., p. 321.—Leidy, ‘Proc. Acad. Phil.,’ viii, p. 53.—Leuckart, l. c., s. 465.—Mayer, Sieb. und Köll. ‘Zeitsch. f. wiss. Zool.,’ Bd. ix, s. 367; Bd. x, s. 233, and s. 383, 1858–60.—Mérat, ‘Dict. Sc. Méd.,’ p. 560.—Von Siebold, ‘Wiegm. Arch.,’ 1845.—Wilson, E., ‘The Veterinary Record and Trans.,’ vol. ii, p. 47, 1846.
Filaria Bancrofti, Cobbold.—The history of the discovery of this entozoon is second only in interest to that of Trichina spiralis. Step by step the facts have been evolved by a slow process of observation, and from the data thus afforded a tolerably connected narrative of the probable life-cycle of this entozoon may now be offered. To place matters beyond all doubt much remains to be done; yet that which has been accomplished is, or ought to be, of surpassing interest alike to the physician, the scientific pathologist, the epidemiologist, and the philosophic naturalist. In the case of Trichina, Owen’s nomenclature was most properly allowed to stand; but for reasons stated below I have not hesitated to employ for this worm, in its adult state, a name differing from that originally given to the hæmatozoon which turns out to be its representative larval state. Although the male parasite is at present unknown, the following characters will in the meantime suffice for a diagnosis of the species:—Body capillary, smooth, uniform in thickness. Head with a simple circular mouth, destitute of papillæ. Neck narrow, about one third of the width of the body. Tail of female simple, bluntly pointed; reproductive outlet close to the head; anus immediately above the tip of the tail. Length of largest females, 31/2 in.; breadth, 1/90″; embryos, 1/200″ to 1/125″ in length, by 1/3000″ to 1/2250″ in breadth; eggs, averaging 1/1000″ by 1/1650″ from pole to pole.
The first discovery of this entozoon, in its embryo state, was made by Wucherer on the 4th of August, 1866. To use Dr Da Silva Lima’s words:—“At the moment when Wucherer was seeking for the Bilharzia hæmatobia, he found instead of it an unknown worm. Our illustrious collaborator,” adds Dr Lima, “has made his important discovery known under the modest title of ‘Preliminary Notice on a species of Worm at present not described;’ and still more modestly Wucherer formulated in the following manner his judicious and prudent conclusions:—It would be rash on my part to put forth a conjecture on the coexistence of these worms of the hæmatochyluria, and on the etiological signification which they might have. I shall therefore abstain until I have been able to make more ample investigations, and until I have been permitted to examine the corpse of a hæmaturic, which has not yet been possible.” (‘Gazeta Medica da Bahia,’ Dec., 1868, p. 99.)
In the year 1868 Dr J. H. Salisbury referred certain ova which he found in the urine to a new and distinct species of nematode. Although he had no acquaintance with the adult parasite, Dr Salisbury at once placed the “species” in the genus Trichina. Here is what he says:—“Trichina cystica (Salisbury).—This is a small species which I have found in the human bladder. In all my examinations I have met with this little entozoon in three cases only. In two of these it was only occasionally met with in the urine. In the other it occurred in great numbers. Frequently from ten to fifteen ova were found in a single drop of urine.”
It is important to remark, that there was no hæmaturia in the last-named case, which Dr Salisbury describes as one of “cystinic rheumatism,” or “severe cystinæmia associated with rheumatism and paralysis.” The patient “had been insane for several years. Her urine was passed milky, with granular cystine, and was dense and scanty.” It is likewise added: “No examination was made of the muscles after death to determine whether this species burrowed in the tissue, like the (Trichina) spiralis.”
So much for the principal facts recorded by Dr Salisbury. His paper is accompanied by two woodcut figures of the ova (× 300 diam.), and one representation of the embryo (× 1000 diam.). If these figures give the size correctly, the ova measure only about 1/800″ in length, by 1/1560″ in breadth, whilst the embryo would be about 1/500″ from head to tail.
