Additional references to the echinococcus disease as it occurs in animals will be found at the close of the section devoted to the parasites of Ruminants (Bibliography No. [49]), and I shall recur to the subject of mortality from “worms” further on.
SECTION III.—Nematoda (Round Worms).
Trichina spiralis, Owen.—The progressive triumphs of biological science are well epitomised in the history of the discovery, and in the record of the gradual manner in which we have obtained our present complete knowledge of the structure and development of this small entozoon.
Although the facts connected with the original discovery are clear and indisputable, much error still pervades foreign literature on this head. Without a doubt Mr Hilton was the first to suggest the parasitic nature of the capsules first spoken of as “gritty particles.” With Sir James Paget, however, rests the true discovery and determination of the nematoid character of the worm itself. With Professor Owen remains the honor of having first scientifically verified, described, and named the entozoon. Some have sought, without good reason, to alter Owen’s nomenclature; yet not only the generic title, but nearly all else that he wrote concerning the parasite, must be allowed to stand.
In relation to the capsules, it is true that prior claims of discovery have been put forward; but whilst Peacock’s preparation of the “little bodies” testifies to the fact of his having seen the capsules before other English observers, including Wormald, it was Hilton who first surmised their parasitic character. As for the claims of Klencke and Tiedemann, they are practically of no value, even if it be admitted that the former may have at an early period seen something resembling this nematode, and that the “stony concretions” encountered by the latter were degenerated capsules.
On no subject have I desired to write with more accuracy and precision than on this, and lest the above remarks should appear to be somewhat partial, I now purposely re-state the facts as they have presented themselves to me during a full and prolonged study of the entire literature of the subject. If it be asked with whom rests the discovery of Trichina, the reply must be framed with a due regard to precise issue at stake. The first recognition of the capsules as parasitic products is fairly claimed by Hilton; the worm by Paget; the zoological allocation and nomenclature by Owen; the adult worm by Virchow; the developmental phenomena by Leuckart; the rearing of the larvæ by Herbst; and to crown all, the clinical importance of the parasite by Zenker. Due regard being had to these relative claims, I think the following more extended statement will be found to be true and just in all its bearings.
Fig. 35.—Sexually mature Trichina spiralis; male. After Leuckart.
In the year 1834 Sir James Paget, then a student, first actually determined the existence of the nematode entozoon, which was subsequently more completely described by Professor Owen. The discoverer was assisted by the celebrated botanist, Robert Brown, who lent his microscope for the purposes of examination. In the following year Professor Owen first scientifically described and named the flesh-worm (Trichina spiralis) in the published transactions of a learned society. He first fully interpreted the true zoological position of the parasite. Sir J. Paget’s colleague, Mr. Wormald, had “more than once” previously noticed the characteristic specks “in subjects dissected at St Bartholomew’s Hospital.” He transmitted the individual specimens which enabled Owen to draw up his valuable paper. It is clear, however, that Mr Hilton was the first to suggest the parasitic and animal nature of the specks observed in human muscle. As the “find” was made in 1832, he anticipated Wormald in his observation of the “gritty” particles in dissecting-room subjects, describing the bodies as “probably depending upon the formation of very small Cysticerci.” Nevertheless, according to Dr Hodgkin, “the first observation of these little bodies was made in 1828” by Mr H. Peacock. The latter made a dry preparation of the sterno-hyoideus muscle to display the specks. That preparation is the oldest in existence, and may be seen in Guy’s Museum. It may further be remarked that Henle, Küchenmeister, Davaine, myself, and others, have pointed to a notice by Tiedemann as probably, or possibly, indicating a prior observation of the specks. Leuckart rejects the evidence. Dr Pagenstecher appears to be in doubt as to the nature of the bodies in question. As the passage in question possibly gave a rough and imperfect description of the now familiarly known calcified Trichina capsules, I give a translation of it (Froriep’s ‘Notizen,’ 1822, Bd. i, s. 64):—“At a post-mortem examination of a man who had been a great brandy-drinker, and who died from thoracic dropsy after several severe attacks of gout, Tiedemann found white stony concretions in most of the muscles, especially at the extremities. They lay in the cellular tissue between the fibre-bundles, frequently also attached to (or near) the walls of the arteries, being from two to four lines long, and roundish. The chemical examination conducted by Gmelin yielded seventy-three parts phosphate of lime, seven parts carbonate of lime and twenty parts animal matter, resembling albumen or fibrin.” In regard to this notice Dr Pagenstecher (‘Die Trichinen,’ s. 4) has remarked that Tiedemann’s “communication was also referred by Henle to such a parasitic development when he subsequently found Trichina; and in this sense it was afterwards received by Diesing, Küchenmeister, and Davaine. But it has been rejected by Leuckart on account of the size (from two to four lines) and seat of the concretions. True, it has never yet been observed that the capsuled Trichina (not measuring a tenth part of that diameter) subsequently constituted centres of gouty deposit exceeding their own bulk, nor is it likely that they should. Seeing, however, as we often do, that errors respecting size have crept into works on Trichina, we shall not need to lay much stress upon these statements; still less so since the notice is very superficial, and its character is essentially of a physiologico-chemical nature. But this, at least, seems to us decisive, that when Bischoff, at Heidelberg, wrote on a case which occurred in Heidelberg, not one single word was mentioned respecting a former case, if such should have happened, although Tiedemann and himself were on terms of close intimacy.” So much for Tiedemann. In regard to Klencke’s claims, the same observer writes:—“Klencke has asserted that he had already drawn Trichinæ in the year 1829, and that he had seen them again in 1831. This subsequent statement has no kind of confirmation. The unreliableness, mistakes, and self-deceptions in the helminthological writings of Klencke have been repeatedly exposed some twenty years ago.” Prior to this criticism by Pagenstecher, Professor von Siebold and several other well-known helminthologists had already commented on Klencke’s assertions in the same destructive manner.