Whatever notions people may entertain respecting the dignity of the human race, there is no gainsaying the fact that we share with the lower animals the rather humiliating privilege and prerogative of entertaining a great variety of parasites. These are for the most part entozoal in habit. As the parasites are apt to cause suffering to the bearer, a superstitious age sought to interpret their presence as having some connection with human wrong-doing. We can now afford to smile at such erroneous ideas. The intimate relation subsisting between parasitic forms dwelling in man and animals, and their interdependence upon one another, alone suffices to preclude the idea that parasites have been arbitrarily placed within the human bearer. It would seem, indeed, that our existence is essential to the welfare and propagation of certain species of parasites. Possibly it is only by accepting the hypothesis of “Natural Selection” that we can escape the somewhat undignified conclusion that the entozoa were expressly created to dwell in us, and also that we were in part designed and destined to entertain them. View the matter as we may, the internal parasites of man and animals strictly conform to a few well-known types of structure, but these types branch out into infinitely varied specific forms. The vulgar mind sees nothing attractive in the morphology and organisation of a parasitic worm, and common-place conceptions of the beautiful cannot be expected to embrace within their narrow grasp the marvelous harmony and order that pervade the structure and economy of the individual members of this remarkable class of beings.
Fasciola hepatica, Linneus.—The first form I have to consider is the common liver fluke. The part this entozoon plays in the production of disease will be fully stated when treating of the parasites of the sheep and other ruminants. About twenty instances of its occurrence in the human body have been recorded. It has been found beneath the skin in the sole of the foot (Giesker), and also under the scalp (Harris), and behind the ear (Fox). Its more frequent seat is in the liver and gall-ducts (Pallas, Brera, Bidloo, Malpighi) and gall-bladder (Partridge). The alleged cases by Bauhin, Wepfer, and Chabert are spurious, as is probably also that given by Mehlis. Duval’s case appears to be genuine, but the occurrence of the worm in the portal vein was accidental. Dr Murchison has recorded a case, occurring at St Thomas’s Hospital, where a solitary specimen was found in the liver. Dr H. V. Carter also met with the worm in a young Hindoo.
In the second half of the present work I shall reproduce Blanchard’s admirable figure of the sexually mature worm (Fig. 61), accompanied by a categorical statement respecting the known facts of development. In this place, however, I may observe that the cases recorded by Giesker, Harris, and Fox had clearly pointed to the circumstance that the higher larvæ of this fluke must be armed cercariæ, otherwise they could not have bored their way through the human skin. As we shall see, Dr Willemoes-Suhm’s investigations have furnished evidence as to the truth of this supposition. For anatomical details I refer to my introductory treatise. In the adult state the liver fluke has been known from the earliest times. We have clear evidences that it was described by Gabucinus in the year 1547, and also subsequently by Cornelius Gemma, who, in a work published some thirty years later, refers to an epizootic disease prevalent in Holland during the year 1552, and which was very justly attributed to the parasite in question. After this date many writers described the liver fluke more or less accurately, and entire volumes were devoted to the consideration of the formidable disease which it occasions. The nomenclature of the parasite has been a subject of controversy. Amongst naturalists in general the common liver fluke is often described under the combined generic and specific name of Distoma hepaticum; but the title is both incorrect and inappropriate. The proper generic appellation of this parasite is Fasciola, as first proposed by the illustrious Linneus (1767) and subsequently adopted by F. Müller (1787), Brera (1811), Ramdohr (1814), and others. Unfortunately Retzius (1786) and Zeder (1800) changed the generic title without good cause, and the majority of writers, following their authority, refused to employ the original name, although a consideration of the distinctive types of structure severally displayed by the genera Distoma and Fasciola fairly demanded the retention of the Linnean title. In later times M. Blanchard (1847) strongly advocated the original nomenclature, and I have myself continually urged its adoption. On somewhat different grounds Professor Moquin-Tandon followed the same course.
In the sexually mature state the liver fluke commonly measures three fourths of an inch in length, occasionally reaching an entire inch or even sixteen lines; its greatest breadth also varying from half an inch to seven or eight lines transversely; body very flat, presenting distinct dorsal and ventral surfaces, frequently curled toward the latter during life; upper or anterior end suddenly constricted, produced and pointed in the centre, forming the so-called head and neck; posterior extremity less acuminated, sometimes rounded, or even slightly truncated; margins smooth, occasionally a little undulated, especially towards the upper part; oral sucker terminal, oval, rather smaller than the ventral acetabulum, which is placed immediately below the root of the neck; reproductive orifices in the middle line, a little below the oral sucker; intromittent organ usually protruded and spirally curved; a central, light-coloured space, covering two thirds of the body from above downwards, marks the region of the internal male reproductive organs, being bordered on either side and below by a continuous dark band, indicating the position of the so-called yolk-forming organs; a small, brown-coloured, rosette-like body situated directly below the ventral acetabulum, marks the limits of the uterine duct; a series of dark lines, branching downwards and outwards on either side, indicate the position of the digestive organs; general color of the body pale brownish yellow, with a slight rose tint. The surface of the body, though smooth to the naked eye, is clothed throughout with small epidermal spines which diminish in size towards the tail.
If any argument were necessary to show how desirable it is to furnish full descriptions of the commoner kinds of parasite, I could adduce numerous instances that have been brought under my notice where professional men and others have been entirely mistaken as to the essential nature of their parasitic finds. Thus, I have known an instance where a great authority on the diseases of dogs has persisted in asserting for the free proglottides of a tapeworm a nematode origin; and, in like manner, human tapeworm-segments have frequently been mistaken for independent fluke parasites. One of the most remarkable instances of this kind is that which I have elsewhere described as an error on the part of Dr Chabert. My reasons for so regarding his interpretation of the facts observed by him stand as follows:
In the ‘Boston Medical and Surgical Journal’ for the years 1852–53–54, Dr J. X. Chabert described several cases of Tænia, and he averred that the tapeworms were associated with numerous specimens of Distoma hepaticum. The passage of distomes by patients during life was even regarded by Dr Chabert as indicative of the presence of Tænia within the intestines. Surely, I remarked, Dr Chabert was mistaken. Are not these so-called distomes the well-known proglottides? Not willingly doubting Dr Chabert’s statements, but desirous, if possible, of verifying the accuracy of his conclusions, I wrote to him (March 22nd, 1864) requesting the loan of a specimen, but I was not fortunate enough to receive a reply. In the “Case of Tænia” in a boy four and a half years old, given in the 49th vol. of the journal, Dr Chabert writes as follows:—“In consequence of his passing the Distoma hepaticum, I concluded he must be afflicted with Tænia.” Further on it is added, that the administration of an astringent injection “caused the discharge of innumerable small worms (Distoma hepaticum).” I think this is quite decisive. The idea of “innumerable” flukes being expelled in this way is altogether out of the question.
The only genuine case in which any considerable number of Distomata, of this species, have been observed in the human subject is the one recently recorded by Dr Prunac. In this instance two flukes were vomited along with blood immediately after the administration of salines (sel de Seignette), and about thirty were passed per anum. On the following day, some tapeworm proglottides having been evacuated, both salts and male-fern extract were administered. This caused the expulsion of an entire tapeworm, and also about twenty more flukes. Notwithstanding this successful treatment the hæmatemesis returned in about a month, when, finally, three more flukes were vomited and the bleeding ceased. Had not the parasites been submitted for identification to a competent observer (Prof. Martins, of Montpellier), some doubt might have been entertained as to the genuineness of this remarkable case. In reference to Dr Prunac’s comments on the facts of fluke-parasitism in man, I will only remark that Dr Kerr’s Chinese cases, to which he refers, were probably due to Distoma crassum and not to D. hepaticum. The Chinese flukes will be noticed below.
Bibliography (No. 3).—Full references to details of the cases by Partridge, Fox, and Harris are given in Appendix B. to Lankester’s Edit. of Küchenmeister’s Manual. See also the works of Davaine and Leuckart (l. c. Bibl. No. 1).—Carter, H. V., “Note on Distoma hepaticum” (from a patient under the care of Mr Pandoorung), ‘Bombay Med. and Physical Soc. Trans.’ (Appendix), 1862.—Chabert, J. X. (quoted above). Murchison, C., ‘Clinical Lectures on Diseases of the Liver,’ (2nd Edit., Appendix), London, 1877.—Prunac, De la Douve ou Distome hépatique chez l’homme; in ‘Gazette des Hôpitaux’ for December, 1878 (p. 1147). For further references in this work, see Bibliog. No. 49.
Distoma lanceolatum, Mehlis.—At least three instances of the occurrence of this small fluke in the human body have been observed. The authority for these cases rests, severally, with Bucholz, who found them in the gall bladder in considerable numbers at Weimar; with Chabert, who expelled a large number from the intestines of a girl in France; and with Küchner, who obtained forty-seven specimens from a girl in Bohemia. Probably many similar instances have been overlooked, and Küchenmeister hints that Duval’s parasites (above mentioned) may have been this species. Although this worm will again be incidentally noticed in connection with bovine parasites (and its ciliated larvæ will also be referred to when discussing the characters of the embryo of Bilharzia), I here subjoin a diagnosis of the characters of the adult parasite. The lancet-shaped liver fluke is a small flat helminth, measuring rather more than the third of an inch in length, and about one line and a half in breadth, being also especially characterised by its lanceolate form; the widest part of the body corresponds with a transverse line drawn across the spot where the vitellaria terminate below, and from this point, on either side, the width of the animal becomes gradually narrowed towards the extremities; both ends are pointed, but the inferior or caudal one more obtusely than the anterior or oral end; the general surface is smooth throughout, and unarmed; the reproductive orifices are placed in the central line immediately in front of the ventral sucker, and below the point at which the intestine bifurcates; the oral sucker is nearly terminal, and 150″ in breadth, the ventral acetabulum being about the same diameter; the testes form two lobed organs placed one in front of the other in the middle line of the body and directly below the ventral sucker; the uterine canal is remarkably long, forming a series of tolerably regular folds, which occupy the central and hinder parts of the body, reaching almost to the caudal extremity. The vitelligene glands cover a limited space, on either side of the centre of the body near the margin. The foramen caudale communicates with a contractile vesicle, which passes upwards in the form of a central trunk-vessel, early dividing into two main branches; these latter reach as far forwards as the œsophageal bulb, opposite which organ they suddenly curve upon themselves, retracing their course for a considerable distance backwards; the digestive canals are slightly widened towards their lower ends, which occupy a line nearly corresponding with the commencement of the lower fifth of the body; the ova are conspicuous within the uterine folds, which present a dark brownish color in front, passing to a pale yellow color below.
In reference to Kichner’s remarkable case I reproduce an abstract of it from Leuckart’s account (‘Die menschlichen Parasiten,’ Bd. i, s. 608), the original particulars of which were communicated to Leuckart by Dr Kichner himself:—
“Dr Kichner’s patient was a young girl, the daughter of the parish shepherd at Kaplitz, having been accustomed to look after the sheep ever since she was nine years old. The pasture where the animals fed was enclosed by woods, being traversed by two water dykes, and being, moreover, also supplied by ten little stagnant pools. These reservoirs harboured numerous amphibia and mollusks (such as Lymnæus and Paludina), and the child often quenched her thirst from the half putrid water. Probably she also partook of the watercresses growing in the ditches. At length her abdomen became much distended, the limbs much emaciated, and her strength declined. Half a year before death she was confined to her bed, being all the while shamefully maltreated by her step-mother. Dr Kichner only saw her three days before her death, and ascertained that she had complained of pain (for several years) over the region of the liver. A sectio cadaveris was ordered by the Government, when (in addition to the external evidences of the cruel violence to which the poor creature had been subjected) it was found that she had an enormously enlarged liver, weighing eleven pounds. The gall-bladder which was very much contracted and nearly empty, contained eight calculi and forty-seven specimens of the Distoma lanceolatum, all of which were sexually mature.”
As I have remarked in a former comment on this singular case, one can have no difficulty in arriving at the conclusion that these parasites were obtained from the girl’s swallowing trematode larvæ, either in their free or in their encysted condition. Leuckart says it was not possible to ascertain whether the parasites had any connection with the gall-stones, or whether the two maladies, so to speak, were independent of each other; yet this question might possibly have been solved if the calculi had been broken up in order to ascertain their structure. It is just possible that dead distomes may have formed their nuclei, and if so, the circumstance would, of course, point to the worms as the original source of the malady.
So far as I am aware, the actual transformations undergone by the larvæ of Distoma lanceolatum have not been observed. The Planorbis marginatus has been confidently referred to as the intermediate bearer of the cercariæ of the common fluke, and Leuckart supposes that the same mollusk harbours the larvæ of this species. The ciliated embryos carry a boring spine or tooth, and it is most probable that the higher larvæ are similarly armed.
Bibliography (No. 4).—Kichner (see Leuckart), quoted above.—Cobbold, ‘Entozoa’ (p. 187).—The case by Bucholz (reported as one of Fasciola hepatica) is given by Jördens in his work (quoted by Diesing and Leuckart) ‘Entomologie und Helminthologie des menschlichen Körpers,’ (s. 64, tab. vii, fig. 14), 1802.—Chabert’s French case is quoted by Rudolphi in his ‘Entozoorum sive vermium,’ &c. (loc. cit., Bibl. No. 1), p. 326, 1808.
Distoma crassum, Busk.—This large species was originally discovered by Prof. Busk in the duodenum of a Lascar who died at the Seamen’s Hospital, 1843. It, however, remained undescribed until 1859, when, with the discoverer’s approval, I gave some account of it to the Linnean Society.
Of the fourteen original specimens found by Mr Busk, several have been lost. The one that he himself gave me I handed over to Prof. Leuckart, and it is figured in his work (‘Die mensch. Par.,’ s. 586). A second is preserved in the museum attached to the Middlesex Hospital, and a third is contained in the Museum of the Royal College of Surgeons. This last-named specimen is the best of the original set. It supplied me with the few details of structure figured in outline in my ‘Introductory Treatise’ (fig. 42, p. 123), published in 1864; and it also in part formed the basis of the description of the species communicated to the Linnean Society in June, 1859 (“Synopsis of the Distomidæ,” p. 5, ‘Proceedings,’ vol. v). The late Dr Lankester, it is true, was the first to give a distinctive title to this entozoon (Distoma Buskii); but as the discoverer objected to this nomenclature, and as Dr Lankester’s proposed terms were unaccompanied by any original description, I requested Mr Busk to suggest a new name for the worm, which he accordingly did. As I subsequently pointed out, Von Siebold had already employed the compound title Distoma crassum to designate a small fluke infesting the house-martin (Hirundo urbica); but for reasons similar to those which contributed to set aside Dr Lankester’s nomenclature, the title adopted in my synopsis at length came to be recognised by Leuckart and by other well-known helminthologists. Before this recognition took place, Dr Weinland, of Frankfort, had so far accepted Lankester’s nomenclature as to call the species Dicrocœlium Buskii. In my judgment there are no sufficient grounds for retaining Dujardin’s genus. Further, I may observe that, in addition to the above-mentioned specimens, two others are preserved in the Museum at King’s College. Thus, only five out of the fourteen specimens are still in existence.
No well-authenticated second instance of the occurrence of this worm took place until the year 1873, when a missionary and his wife from China consulted Dr George Johnson respecting parasites from which they were suffering. After a brief interval, both of Dr Johnson’s patients were by an act of courtesy on the part of this eminent physician placed under my professional care. I need hardly add that Dr Johnson had from the very first recognised the trematode character of the parasites. From the patients themselves I ascertained that they had been resident in China for about four years. During that period they had together freely partaken of fresh vegetables in the form of salad, and also occasionally of oysters, but more particularly of fish, which, in common with the oysters, abound in the neighbourhood of Ningpo. From their statements it appeared to me that to one or other of these sources we must look for an explanation of the fact of their concurrent infection. Fluke larvæ, as we know, abound in mollusks and fish; but whether any of the forms hitherto found in oysters or in fish have any genetic relation to the flukes of man, is a question that cannot very well be settled in the absence of direct experimental proof. I should add that it was not until after their visit to the interior of the country, some 130 miles distant from Ningpo, that the symptoms (which Dr Johnson in the first instance, and myself subsequently, considered to have been due to the presence of the parasites) made their appearance. Whilst in the country the missionary and his wife freely partook of freshwater fish, and on one occasion they received a quantity of oysters that had been sent up from Ningpo. The husband assured me that the fish were always thoroughly well cooked.
If it be asked what were the symptoms produced, I can only furnish such few and hitherto unpublished particulars as the missionary himself supplied. I need hardly say that he was a highly cultured and intelligent gentleman, since only such persons are chosen for missionary work in China.
From inquiries made by me on the 29th of January, 1875, I learnt that they left Ningpo in November, 1872, and travelled thence 130 miles into the interior of the country. In the following September, or about ten months subsequently, the missionary was attacked with diarrhœa, which persisted until expulsion of some of the parasites had occurred. According to the patient’s statements this result, so far, was entirely due to his having been placed on a milk diet; this course of treatment having been recommended by Dr Henderson, of Shanghae. The patient himself always suspected the presence of intestinal worms of some sort or other, although a Japanese doctor laughed at the idea of such a thing. Some other doctor treated this missionary for parasites, administering both male-fern and santonine without effect.
It was not until several months had elapsed that his wife was attacked with diarrhœa. In both cases there was more or less flatus. The motions were white, and there were other indications implying that the liver was affected. Later on, symptoms of indigestion, with heartburn, set in and became very severe. Streaks of blood appeared in the fæces, but there was no dysentery. For the most part these symptoms were attributed to the effects of climate.
When, in the month of February, 1875, I saw the missionary a second time, professionally, I found that all the old symptoms had returned. He had a foul tongue, the surface of the body was cold, he felt chills, and the pulse, though regular, registered ninety-six to the minute. Indigestion, nausea, headache, and diarrhœa had reappeared. Notwithstanding these febrile symptoms, so satisfied was the patient himself that all his ailments were entirely due to the presence of parasites, that I felt inclined to take the same view of his case. Accordingly my attention was principally directed to an effort for their expulsion; and in this view I ordered an aloetic pill followed by a castor-oil emulsion. This having no effect, I subsequently prescribed aloes and assafœtida pills, followed by scammony mixture. The action of the latter drug did not occasion griping, but, although efficient, led only to negative results. I should mention that in the patient’s judgment none of the vermifuges administered to him at any time had exerted any influence in the expulsion of the flukes. He was still thoroughly impressed with the notion that the milk diet, ordered by Dr Henderson, was the sole cause of their expulsion.
As even a missionary could not live by milk alone I insisted upon a more substantial diet. The milk, indeed, had occasionally been supplemented by Liebig’s extract of meat and by light farinaceous food. When I last saw him neither he nor his wife had passed any more flukes, but they did not feel satisfied that no more guests remained. Somewhat improved in general health, the missionary resolved to go back to his duties in China. I expressed my fears, however, that his strength would prove unequal to the work.
From the size and almost leathery texture of the two flukes which were in the first instance submitted to my notice, I at once recognised the species; but as they were spirit-specimens, I requested that if any more examples were obtained they should be sent to me in the fresh state. Fortunately others were brought in a few days, when, from an examination conducted whilst they were still fresh, I was able to make out several details of structure which had hitherto escaped notice. Altogether I secured seven specimens, three of them being in a mutilated condition. In what way these mutilations (as shown by my dried specimens) occurred I have not been able to make out, either by personal observation or by questioning the bearers. Two of the parasites look as though portions had been carefully excised near the centre. The new facts I have gleaned were derived from the examination of two comparatively small specimens, one of which, dried, has, by Prof. Rolleston’s desire, been deposited in the anatomical department of the University Museum at Oxford. When I took occasion to bring some of the new specimens under Mr Busk’s attention, he at once recognised them as referable to the species he had long ago discovered.
The earliest literary notice of Distoma crassum appeared in Dr Budd’s classical treatise ‘On Diseases of the Liver;’ and in it the author correctly stated, from data supplied by Mr Busk, that these human flukes were “much thicker and larger than those of the sheep,” being, it is added, from “an inch and a half to near three inches in length.” The longest of my recent specimens, however, scarcely exceeds two inches, whilst the smallest and most perfect (the one at Oxford) measures less than an inch from head to tail. The greatest width of my broadest specimen is little more than half an inch, or 916″. None of the twelve examples that I have examined approach the length of three inches; but Mr Busk assured me that, judging from his recollection, some of his specimens were even longer than that. I fear, nevertheless, that the estimate given in my Synopsis is somewhat exaggerated; at all events it is so for average specimens.
The new anatomical facts made out by me bear reference principally to the reproductive apparatus. What else I have observed is for the most part confirmatory of the statements made by Mr Busk. In particular, his brief account of the position and character of the digestive organs was not only confirmed by my earlier examinations, but is now re-verified. In the representation given in my ‘Introduction’ I showed in dotted outline two large organs which I supposed to be the testes. I distinctly observed radiating lines proceeding from the centre in each; but I could not discover the slightest trace of any limiting border to either organ. I now found in the same position two nearly circular flattened masses with clearly defined limits (i, k). No doubt could be entertained as to the testicular character of the lower organ (k). In the original drawing I further indicated the presence of a third and much smaller globular mass, which I termed the ovary; but what I supposed to represent this organ in the particular specimen from which the accompanying illustration was drawn turns out to be merely a hernial protrusion resulting from injury (h). The radiating, broad, and branching seminal ducts are beautifully distinct in one of my specimens, forming the most attractive feature of the parasite’s organisation (k). In consequence of injury to the specimen which is here drawn, the upper testis (i) displays no seminal tubes. I made out the female reproductive organs with more completeness. In the outline drawing given in my introductory treatise I had indicated the probable position of the uterine folds; reducing the organ to the simplest expression of what I concluded must obtain in the normal condition. My conjecture was perfectly correct. The uterus consists of irregularly folded tubes, which, though here and there apparently branching from a central tube, are in reality folded evenly upon themselves. The oviduct can be distinctly traced to its outlet in the reproductive papilla, which, as usual in true Distomes, is placed in the middle line, immediately above the ventral sucker. In my examination of Mr. Busk’s original specimens I could not find the slightest trace of vitelligene organs; but in my fresh examples I not only obtained proof that these organs were largely developed, but that their limitations could be fixed with accuracy (g g). They consisted of two large elongated masses, one on either side of the body, occupying about two thirds of the entire length of the parasite. Their yolk-vesicles were distinctly seen; but the main efferent canals were only here and there traceable. Clearly, the position and character of the yolk-forming glands of this large human fluke are quite unlike those of any of its congeners. This fluke is a remarkably fine species, and, when viewed in the fresh state with a powerful pocket-lens, presents a most striking appearance. I did not observe any cutaneous spines. I found the eggs to present an average long diameter of about 1200″, by 1330″ in breadth. They are therefore somewhat smaller than those of the common fluke. In the specimen preserved in the Hunterian Museum there was complete evidence of the presence of an excretory outlet at the caudal extremity; but I did not succeed in finding any trace of the water-vascular system higher up. I have no doubt, however, that it exists.
As regards the affinities of Distoma crassum, it is clear that this Trematode has little in common either with the liver-fluke of cattle and sheep (Fasciola hepatica), or the still larger species obtained by me from the giraffe (Fasciola gigantea). The simple character of the digestive tubes obviously connects it more closely with the lancet-shaped fluke (Distoma lanceolatum), the last-named parasite being, as already shown, an occasional resident in the human liver, where its presence, moreover, undoubtedly contributed towards the production of the fatal result.
In my remarks on the missionary’s diet it is hinted that the Ningpo oysters may have played the rôle of intermediary bearers to the parasite in question; and as tending in some measure to strengthen this notion, it should be borne in mind that Mr. Busk’s original fluke-bearer came from the east. It is not improbable that the Lascar host may have partaken of the same particular species of fish or shell-fish that the missionary and his wife partook of. Be that as it may, the frequency of the occurrence of Trematodes and their larvæ in marine mollusks is well known. According to Woodward, several species of oyster are sold in the Indian and Chinese markets. Thus, it would require the skill of a malacologist to determine the particular species of Ostrea to which the Ningpo oysters should be referred.
Mons. Giard is of opinion that the singular larvæ known as Bucephali attain sexual maturity in sharks and dog-fishes; therefore it is extremely unlikely that the Bucephali should have been in any way concerned in the infection of our missionary and his wife; nevertheless there remains the probability that these human bearers swallowed other kinds of Trematode larvæ when they consumed the Ningpo oysters. Moreover, if it should happen that none of the other larvæ occurring in oysters are capable of developing into flukes in the human territory, it yet remains highly probable that some one or other of the various encysted (and therefore sexually immature) Trematodes known to infest marine fishes will turn out to be the representative of our Distoma crassum. In this connection we must not forget that the flesh of the Salmonidæ forms the probable source of human Bothriocephali; and there is some likelihood that salt-water fishes, if not actually the primary, may become (after the manner explained by M. Giard) the secondary intermediary bearers of fluke-larvæ. At all events, I am inclined to look to the Ningpo oysters, or to some other of the various species of marine shell-fish sold in eastern markets, as the direct source of Distoma crassum; for, in addition to the bucephaloid cercarians, we have abundant evidence of the existence of other and more highly developed fluke-larvæ in marine bivalve mollusks.
In this connection I will only further observe that we possess very little knowledge of the parasites which take up their abode in the viscera of savages. This ignorance results partly from the fact that these untutored races, as proved by the statements of Kaschin and others, actually, in the matter of severe symptoms, suffer much less from the presence of intestinal worms than their civilised fellow-men do. The subject is worthy of further attention, but no one, so far as I am aware, has cared to institute the necessary inquiries in a methodical way. I strongly suspect that several of the human parasites which we now consider to be rare would be found to be abundant if by means of post-mortem examinations and other methods of investigation we could be made acquainted with the facts of helminthism as they occur amongst the raw-flesh and fish-eating savage tribes. Of course any person, notwithstanding the utmost care and cleanliness, as in the cases before us, may contract a noxious parasite; nevertheless, speaking generally, it may be said that the measure of internal parasitism affecting any given class of people bears a strict relation to the degree of barbarism shown by such persons in their choice of food and drink, and in their manner of eating and drinking. This statement, if true, is not destitute of sanitary importance; moreover, it applies not alone to ourselves, but also to all the domesticated animals that serve our wants. Cleanliness is just as necessary for their welfare as for our own.
In the spring of 1878 my patients returned from China. They had experienced fresh attacks from the parasite; moreover, one of their children, a little girl, was also victimised by the same species of fluke. Thus, in one family I have encountered three cases of fluke-helminthiasis due to Distoma crassum! One of the worms passed by the little girl per anum is now in my possession. It not only shows the upper testis perfectly, but also the many times transversely folded, simple, uterine rosette which is certainly not branched. There are also traces of an organ which I take to be the cirrhus-pouch; but I have never seen the penis protruded externally.
For the purposes of diagnosis I subjoin the following characters. The Distoma crassum is a large, flat helminth varying from an inch and a half to two and a half inches in length, and having an average breadth of five eighths of an inch; it is especially also characterised by its uniform and considerable thickness, combined with the presence of a double alimentary canal which is not branched; the body is pointed in front, and obtusely rounded posteriorly; the integument being smooth and unarmed; the reproductive orifices placed immediately above the ventral sucker; the testes form two large rounded organs, situated below the uterine rosette, and disposed in the middle line, one in front of the other; the uterine folds occupy the front part of the body; near the lateral margins there are two large vitelligene glands, one on either side of the intestinal tube; the excretory organ probably consists of a central trunk with diverging branches, opening below.
Bibliography (No. 5).—Budd, original notice in his ‘Diseases of the Liver,’ 2nd edition, quoted by Lankester in Appendix B to Küchenmeister’s ‘Manual of Parasites,’ p. 437, 1857.—Cobbold, T. S., “Synopsis of the Distomidæ,” in ‘Journ. of the Proceed. of the Linnean Soc.,’ vol. v, Zool. Div., 1860 (original description p. 5).—Idem, ‘Entozoa,’ p. 193, 1864.—Idem, “Remarks on the Human Fluke Fauna, with especial reference to recent additions from India and the East,” the ‘Veterinarian,’ April, 1876.—Idem, “On the supposed Rarity, Nomenclature, Structure, Affinities, and Source of the large Human Fluke (D. crassum),” ‘Linn. Soc. Journ.,’ vol. xii, Zool. Div., 1876, p. 285 et seq.—Idem, “Observations on the large Human Fluke, with notes of two cases in which a missionary and his wife were the victims,” the ‘Veterinarian,’ Feb., 1876.—Idem, “The new Human Fluke,” in a letter published in the ‘Lancet,’ Sept., 1875.—Leidy, in ‘Proceed. Acad. Nat. Sciences of Philadelphia;’ see also Dr McConnell’s paper quoted below (Bibl. No. 6).—Leuckart, l. c., Bd. I, s. 560.—Weinland, l. c. (Bibl. No. 2), Appendix, p. 87.
Distoma Sinense, Cobbold.—The discovery of this species is due to Prof. J. F. P. McConnell, who “on the 9th of Sept., 1874, found a large number of flukes in the liver of a Chinese, obstructing the bile ducts.” The species measures 710″ in length, by 17″ in breadth, the eggs being 1833″ by 11666″. Dr McConnell showed in his original memoir that the worm cannot well be confounded with Fasciola hepatica, with Distoma lanceolatum, or with D. conjunctum. In this conclusion he was supported by Dr T. R. Lewis, who examined the specimens with him. In a letter communicated to the ‘Lancet,’ quoted above, I proposed the nomenclature here given; but Prof. Leuckart, unaware of this step, afterwards suggested the terms Distomum spatulatum. Later on I received numerous specimens from Calcutta, the examination of which enabled me to confirm the accuracy of the original description. As regards the male organs in the subjoined figure, it will be seen, by comparing the lettering and references, that I have interpreted the facts of structure somewhat differently from Prof. McConnell.
In the month of December, 1874, a Chinese died in the Civil Hospital at Port Louis, Mauritius, whilst he was under the care of Dr William Macgregor, chief medical officer of the Colony of Fiji. The post mortem revealed the presence of a very great number of flukes in the bile-ducts. Dr Macgregor described these parasites with great care, and having favored me with a copy of his manuscript I at once recognised the worms to be identical with the species discovered by McConnell. I also received through Dr Henry Clark, of Glasgow, two Mauritius specimens, which when compared with the Calcutta examples proved to be specifically identical. Dr Macgregor’s paper, communicated to the Glasgow Medico-Chirurgical Society, gives full particulars of the helminthiasis associated with this parasite, whilst both his and Prof. McConnell’s account of the structure of the worm are remarkably complete in details, and well illustrated. It is not a little curious to notice that although these parasites were obtained in countries far removed from China, they were in both instances taken from Chinese; moreover, from the statements of Macgregor, it appears very probable that the parasites in question are a common source of liver disease. Without doubt oriental habits are eminently favorable to fluke infection, for we are now acquainted with four species of flukes whose geographical range is limited to eastern parts.
Bibliography (No. 6).—McConnell, J. F. P., “Remarks on the Anatomy and Pathological relations of a new species of Liver-fluke,” ‘Lancet,’ Aug. 1875; repr. in the ‘Veterinarian,’ Oct., 1875; also in the ‘Lancet,’ March 16th, 1878, p. 406.—Macgregor, W., “A new form of Paralytic Disease, associated with the presence of a new species of Liver Parasite (Distoma Sinense),” ‘Glasgow Med. Journ.’ for Jan., 1877; also in the ‘Lancet’ for May 26th, 1877, p. 775.—Cobbold, T. S., in a note to the ‘Lancet,’ Sept., 1875, and in the Appendix to Macgregor’s paper, p. 15, 1877.—Leuckart, R., l. c., Bd. ii, s. 871, 1876.
Distoma conjunctum, Cobbold.—The little fluke which I first discovered in the gall-ducts of an American fox (Canis fulvus) was fourteen years afterwards obtained from pariah dogs in India by Dr T. R. Lewis (1872); but it remained for Prof. McConnell to show that this entozoon also invades the human subject (1874). A second instance of its occurrence in man was recorded in 1876. We all figured the worm, and in respect of general details our descriptions for the most part agreed (fig. 56). The worms from the dog and fox gave an average of 14″ in length, but the majority of those found by McConnell in man were fully 38″ from head to tail.
Writing in the spring of 1876 Dr McConnell says:—“In the ‘Lancet’ for the 21st of August, 1875, I published the description of a new species of liver-fluke found in the bile-ducts of a Chinaman (sic) who died in this hospital. Dr Spencer Cobbold has very kindly interested himself in this discovery, and proposed the name of Distoma Sinense for the new fluke. This discovery (in September, 1874) has stimulated me to pay still greater attention to the morbid conditions of the biliary canals in our post-mortem examinations; but, although more than 500 autopsies have been conducted since that date, I have not met with another instance of distomata in the liver until within the last fortnight. On the 9th of January, 1876, in examining the liver of a native patient who had died in the hospital, I again found a large number of flukes in the bile-ducts, and having carefully examined many specimens, I recognise the species as the D. conjunctum of Cobbold. Dr Cobbold discovered this fluke in 1858; but, as far as I am aware, the human liver has never hitherto been found infested by these parasites, and this will give general interest and importance to the following case.”
“Jamalli Khan, a Mahommedan, aged twenty-four, admitted into the hospital on the 25th of December, 1875. He is a resident of Calcutta, and an ordinary labourer (coolie). He states that he had been suffering from ‘fever’ for the last two months, at first intermittent in character, but for the last seven days more or less continued. He is much emaciated and reduced in strength. Complains of pain on pressure over the liver and spleen; the latter can be felt much enlarged, reaching downwards to nearly the level of the umbilicus; the lower border of the liver, however, can only just be felt below the ribs. Temperature on evening of admission 101° F. Conjunctivæ are anæmic, but not jaundiced. Has also a little bronchitis. The fever continued with slight remissions for ten days (January 4th, 1876), the highest diurnal temperature (in the afternoon) varying from 103° to 104° F.; it then abated, but dysentery set in. He began to pass six or eight stools in the twenty-four hours, attended with much griping, and containing varying quantities of blood-tinged, gelatinous mucus. These became more frequent, in spite of treatment, during the next three days, and on the 8th of January he was manifestly sinking; passed his evacuations into the bedclothes, became cold and collapsed, and died in this state that same evening.
“A post-mortem examination was made on the following morning, thirteen hours after death. All the organs of the body were found more or less anæmic, but exhibited nothing remarkable with the following exceptions. The lungs towards their posterior margins and bases were dark, but still spongy and crepitant. The spleen was found greatly enlarged, heavy; capsule tense and stretched; substance soft, reddish brown, irregularly pigmented; weight 1 lb. 13 oz. The liver was of about normal size; its surfaces smooth, the capsule slightly hazy looking. Hepatic substance firm, but abnormally dark, and the bile-ducts particularly prominent and thickened. Numbers of small distomata escaped from the incisions made into the organ, and could be seen protruding from the dilated biliary canals. The gall-bladder was filled with thick greenish-yellow bile, measuring about an ounce and a half, but containing no parasites, and no ova even could be detected on microscopical examination of this bile and of scrapings from the lining membrane of the gall-bladder. The cystic duct was free from obstruction. The condition of the common choledic duct could not so well be ascertained, as the liver had been removed from the abdominal cavity before anything extraordinary had been detected in its condition, but, so far as it could be examined, it was found patent; the duodenal mucous membrane was well bile-stained, and there was evidence of biliary colouring matter in the fæcal contents of the bowels. On carefully dissecting out, and then laying open, the biliary ducts in a portion of the right lobe of the liver (the rest being preserved entire), numbers of distomata were found within them, lying singly, flattened, and generally with the anterior extremity, or “oral sucker,” directed towards the periphery of the organ, the posterior extremity towards its centre; or in twos, threes, or even little groups of fours, variously coiled upon themselves or upon each other. The lining membrane of the biliary canals was found abnormally vascular, its epithelial contents abundant (catarrh?), and, among these, ova could be detected under the microscope. Sections of the liver, hardened and then examined in glycerine, showed fatty infiltration of the lobular structure, but not to any advanced degree; the bile ducts considerably dilated, their walls thick and hypertrophied, but nothing else abnormal, or in any way remarkable. The weight of the liver was 3 lbs. In the transverse and descending colon numerous indolent-looking, shallow, pigmented ulcers were found, and in the rectum others evidently more recent and highly injected. The submucous tissues throughout were abnormally thickened. The intestinal contents consisted of only about three ounces of thin yellowish (bilious) fæcal fluid, with small bits of opaque mucus. This was carefully washed and examined, but no flukes were discovered. About a dozen distomata escaped from the liver on making the primary incisions, and quite twice this number was found subsequently within the biliary canals. Only a portion of the right lobe has, as I have said, been dissected, so that it may be confidently stated that probably not less than a hundred of these flukes must have infested this liver. All were found dead, but it must be remembered that the autopsy was performed thirteen hours after the death of the patient. It is remarkable that in this case, as in the one before described by me, no distomata were found in the gall-bladder. The presence of these parasites in the bile-ducts seems to have led to catarrhal inflammation of their lining membrane and abnormal thickening and dilatation of their walls, but there is no evidence of their having caused sufficient obstruction to produce cholæmia, as in the case just referred to, and no marked pathological change could be detected in the lobular structure of the liver.”
After referring to the anatomical descriptions of the worm, as recorded by myself (in ‘Entozoa’) and by Lewis (in the memoir quoted below), Professor McConnell further observes that the addition of a few more particulars seems necessary for the determination of the identity of the species. He then gives the following characters:
“Body lanceolate, anterior and posterior extremities pointed, the latter obtusely. Surface covered with minute spines or hairs. Average length 38″ (three eighths of an inch); average breadth 110″. ‘Ventral’ sucker slightly smaller than ‘oral.’ Reproductive papilla or genital orifice placed a little above and to one side of the former. Alimentary canal double and unbranched. Uterine folds and ovary placed in the median line, and above the male generative organs, the latter consisting of two very distinct globular bodies or testes. Ova of the usual type, i.e. oval in outline, having a double contour, and granular contents; average length, 1750″; average breadth, 11333″. The only point of note is that the average length of these flukes is greater than that of the same species found by the authors above referred to. The D. conjunctum in the American fox, and in the pariah dog, has an average length of 14″; only two or three specimens of this size were found in this liver, and these showed evidences of immaturity; a few were found 12″ in length; but the great majority exactly 38″. The anatomical characters are otherwise precisely identical.”
Professor McConnell concludes his communication by a remark in reference to the common source of infection shared by mankind and dogs in India. The occurrence, however, of this entozoon in an American red fox points to a very wide geographical distribution of the species. It is hardly likely that the fox, though dying in the London Zoological Society’s Menagerie, should have contracted the parasite in England. In the second half of this work I shall reproduce my original drawing (fig. 56) from the ‘Linnean Transactions;’ but I may refer to my Manual (quoted below) for a reproduction of McConnell’s figure. In my original specimens the integumentary spines had fallen, probably as a result of post-mortem decomposition.
Bibliography (No. 7).—Cobbold, T. S., “Synopsis of the Distomidæ,” (l. c.), 1859; and in “Further Observations on Entozoa, with experiments,” ‘Linn. Trans.,’ vol. xxiii (tab. 33, p. 349), 1860.—Idem, “List of Entozoa, including Pentastomes, from animals dying at the Zool. Soc. Menagerie between the years 1857–60,” ‘Proceed. Zool. Soc.,’ 1861.—Idem, ‘Entozoa,’ p. 20, pl. ii, 1864; and in “Manual of the Internal Parasites of our Domesticated Animals,” p. 81, 1873.—Lewis, T. R., and Cunningham, D. D., in a footnote to their ‘Microscopical and Physiological Researches,’ Appendix C., ‘Eighth Ann. Rep. of the San. Comm. with the Govt. of India,’ p. 168, Calcutta, 1872.—McConnell, J. F. P., “On the Distoma conjunctum,” in the ‘Lancet’ for 1875–76, quoted above; reprinted in the ‘Veterinarian,’ 1876; also (a second case) in the ‘Lancet’ for March 30th, 1878, p. 476.