SECTION I.—Trematoda (Flukes).
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].
Fig. 1.—The lancet-shaped fluke (Distoma lanceolatum), showing the disposition of the digestive and reproductive organs internally. Viewed from behind; mag. about 12 diameters. After Blanchard.
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 1/50″ 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 9/16″. 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.
Fig. 2.—The large human fluke (Distoma crassum) a, Oral sucker; b, intestine; c, cæcal end of same; d, reproductive papilla; e, uterine rosette (the folds of which are not branched); f, one of the folds (in profile); g, vitellarium; h, hernial protrusion (the result of an injury to the specimen); i, upper testis; j, streaks or layers of seminal fluid which have escaped by rupture and assumed a branched appearance; k, lower testis uninjured (but slightly altered in outline from flattening); l, ventral sucker. Magnified 2 diameters. Original.
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 1/200″, by 1/330″ 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.
Fig. 3.—The Chinese fluke (Distoma Sinense). a, Oral sucker; b, œsophageal bulb; c, intestine; c′, cæcal end; d, ventral sucker; e, genital pore; f, uterine folds; g, ovary; h, vitellarium; i, vitelligene duct; k, upper seminal reservoir; l, testes; m, lower seminal pouch; o, vas deferens; p, pulsatile vesicle; p′, water vessel. After McConnell.
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 7/10″ in length, by 1/7″ in breadth, the eggs being 1/833″ by 1/1666″. 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 1/4″ in length, but the majority of those found by McConnell in man were fully 3/8″ 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 3/8″ (three eighths of an inch); average breadth 1/10″. ‘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, 1/750″; average breadth, 1/1333″. 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 1/4″; only two or three specimens of this size were found in this liver, and these showed evidences of immaturity; a few were found 1/2″ in length; but the great majority exactly 3/8″. 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.
Fig. 4.—The small Egyptian fluke (Distoma heterophyes), viewed from behind. The large ventral sucker, supplementary disk, uterus, testes, simple divided intestine, vitellarium, and pulsatile vesicle are conspicuous. Original.
Distoma heterophyes, Von Siebold.—This minute parasite, measuring only 3/4 of a line in length, was discovered by Dr Bilharz, of Cairo, in the intestines of a lad, post-mortem, in the year 1851. A second similar instance occurred, when several hundred examples were collected and afterwards distributed amongst the helminthologists of Europe. Through the kindness of Leuckart two of the worms eventually reached myself. From one of these the accompanying figure was drawn. For the purpose of supplying a full diagnosis I have elsewhere described this worm as presenting an oblong, pyriform outline, attenuated in front, and obtusely rounded behind; body compressed throughout, the surface being armed with numerous minute spines, which are particularly conspicuous (under the microscope) towards the head; oral and ventral suckers largely developed, the latter being near the centre of the body, and about twice the diameter of the former; pharyngeal bulb distinct and separate from the oral sucker, and continued into a long œsophagus, which divides immediately above the ventral acetabulum; intestinal tubes simple, gradually widening below and terminating near the posterior end of the body; reproductive orifices inconspicuous, but evidently placed below and a little to the right of the ventral sucker, at which point they are surrounded by a special accessory organ, resembling a supernumerary sucker; uterine folds numerous and communicating with small but conspicuously developed vitelligene glands; testes spherical and placed on the same level in the lower part of the body; ovary distinct; aquiferous system terminating inferiorly in a large oval contractile vesicle, the latter opening externally by a central foramen caudale.
Apart from its minuteness, moreover, this trematode is especially characterised by the possession of a very remarkable apparatus surrounding the reproductive orifices. It consists of an irregularly circular disk, measuring 1/125″ in diameter, and having a thick-lipped margin, which supports seventy fish- basket-like horny ribs comparable to the claw-formations seen in the genus Octobothrium. According to Bilharz these ribs give off five little branches from their sides, but Leuckart could not see them in his specimens. Leuckart estimated the length of these horny filaments to be 1/1250″, whilst their breadth was 1/3570″. On the whole we may regard this organ as a complicated form of “holdfast” designed to facilitate or give efficiency to the sexual act. I may here also state that this structure is by no means unique; for, if I mistake not, it exists in an equally developed degree in the young trematode which Dr Leared found infesting the heart of a turtle. Leared believed that he had found an ordinary distome; an opinion to which I could not give my assent, seeing that the organ described by him as a “folded, ventral sucker” presented a very different aspect to the oral sucker displayed by the same animal. Without doubt, however, the organ in his so-called Distoma constrictum is analogous to the supplementary “holdfast” existing in Distoma heterophyes. The views which I originally advanced as to the source and condition of the parasite are probably correct.
As regards the structure of Distoma heterophyes, I have only to add that a special set of glandular organs is situated on either side of the elongated œsophagus, but the connection between these organs and the digestive apparatus has not been clearly made out. Leuckart compares them to the so-called salivary glands found in Distoma lanceolatum, and says, “The presence of such a glandular apparatus is also indicated by the more ventral position of the oral sucker, and the development of the cephalic margin.” The conspicuous contractile vesicle terminating the excretory system is developed to an unusually large extent, exhibiting in its interior multitudes of the well-known active molecular particles. Lastly, I have only to add that the eggs of Distoma heterophyes measure 1/990″ in length by 1/666″ transversely.
Fig. 5.—The eye fluke (Distoma ophthalmobium). Showing the suckers and intestinal tubes. After Von Ammon.
Bibliography (No. 8).—Bilharz, “Beitrag zur Helminth. humana,” ‘Zeitsch. für wissenschaftl. Zool.,’ s. 62, 1851.—Cobbold, ‘Entozoa,’ p. 195, 1864.—Küchenmeister, F., ‘Parasiten,’ 1855, s. 210, Eng. edit., p. 276, 1857.—Leared, “Description of Distoma constrictum,” ‘Quarterly Journal of Micros. Science,’ new series, vol. ii, 1862.—Leuckart, R., l. c., s. 613, 1863.—Moquin-Tandon, on the Genus Fasciola, l. c., 1861.—Weinland, on Dicrocœlium, l. c., p. 86, 1858.
Distoma ophthalmobium, Diesing.—There is every reason to believe that the small flukes found by Gescheid and Von Ammon in the human eye were sexually immature worms, but since it cannot be decided as to what adult species they are referable I prefer to notice them under the usual title. Possibly these eye-worms may be referred to D. lanceolatum, as suggested by Leuckart. However that may be, I deem it unnecessary to repeat the details recorded in the treatises quoted below. The largest examples measured only half a line or about one millimètre in length.
Bibliography (No. 9).—Cobbold, ‘Entozoa,’ p. 191.—Gescheid (D. oculi humani), in Von Ammon’s ‘Zeitsch. f. Ophth.,’ iii, and also in Ammon’s ‘Klin. Darstell. d. Krankheit d. Menschl. Auges.,’ vols. i and iii.—Küchenmeister, Eng. edit., p. 287.—Leuckart, l. c., s. 610.—Nordmann (Monostoma lentis), “Mikr. Beitr.,” Heft. ii, ‘Vorwort,’ s. ix, 1832.
Tetrastoma renale, Chiaje; Hexathyridium pinguicola, Treutler; and H. venarum, Treutler.—Whether these forms are good species or not, the fact that they were genuine parasites cannot, I think, be disputed. The first-mentioned measured five lines in length, and was found by Lucarelli in the urine. The second, eight lines long, was found by Treutler in a small tumour connected with the ovary. The third, measuring three lines in length, was twice found in venous blood, and twice in the sputum of patients suffering from hæmoptysis.
Bibliography (No. 10).—Delle-Chiaje, ‘Elmintografia Umana,’ 1833.—Bremser (l. c., Bibl. No. 2), s. 265, 1819.—Cobbold, ‘Entozoa’ (p. 204, et seq.).—Dujardin (l. c., Bibl. No. 2), s. 265, 1819.—Treutler, ‘Obs. Path. Anat. ad Helm. Corp. Humani,’ p. 19, 1793.—Zeder, ‘Anleitung zur Naturg. der Eingeweidewürmer,’ s. 230, 1803.
Amphistoma hominis, Lewis, and McConnell.—The original account of this species is based upon two finds. The first series of specimens was procured from Dr J. O’Brien, of Gowhatty, and the second set from the Pathological Museum of the Calcutta Medical College. Dr O’Brien and Dr Curran together procured their specimens, post-mortem, from an Assamese. There were hundreds of worms present in the vicinity of the ileo-colic valve. The museum specimens were procured from a patient who died at the Tirhoot gaol hospital in 1857. They were (say the authors) presented to the museum by Dr Simpson, and in the catalogue their history was briefly recorded as follows:
Fig. 6.—The human amphistome (Amphistoma hominis). Longitudinal section. a, Oral sucker; b, pharyngeal bulb; c, nerve ganglia; d, œsophagus; e, genital pore; f, vagina; g, ductus ejaculatorius; h, ventral nerve cords; i, intestinal canal; j, upper testis; k, water vessel; l, lower testis (ovary according to Lewis); m, principal ducts of the vitellarium; n, branches of the vitellary ducts; o, ventral pouch or bursa; p, caudal sucker. Magnified 12 diameters. After Lewis.
“The cæcum of a native prisoner who died from cholera in the Tirhoot gaol hospital, with a number of peculiar and, probably, hitherto unrecognised parasites, found alive in that part of the intestinal canal.” (Presented by Dr Simpson through Professor E. Goodeve.)
In continuation of their narrative, Drs Lewis and McConnell go on to say that, “with reference to this preparation, the following very interesting particulars from the ‘Annual Jail Report of Tirhoot’ for 1857 have been very kindly placed at our disposal by the Surgeon-General, Indian Medical Department. The prisoner, Singhesur Doradh, aged 30, was attacked with cholera on the 13th, and died on the 14th of July, 1857. Had not been in hospital previously, and was employed in cleaning the jail.”
The post-mortem examination was made three hours after death:—“Colon externally livid, contracted; contains a little serous fluid with flakes of mucus. Mucous membrane healthy except venous injection. In the cæcum and ascending colon numerous parasites like tadpoles, alive, adhering to the mucous membrane by their mouths. The mucous membrane marked with numerous red spots like leech-bites from these parasites. The parasites found only in the cæcum and ascending colon, none in the small intestines.” This description is by Dr Simpson, who adds, “I have never seen such parasites, and apparently they are unknown to the natives. They are of a red colour, size of a tadpole, some young, others apparently full grown, alive, adhering to mucous membrane,—head round, with circular open mouth, which they had the power of dilating and contracting. Body short and tapering to a blunt point.”
Drs Lewis and McConnell’s description of the worm is too long to be quoted in full. The parasites measure 1/5″ to 1/3″ in length, by 1/8″ to 1/6″ in breadth. Science is much indebted to these eminent observers for having unearthed the museum specimens and for recording the facts they could gather. From a zoological point of view the most interesting fact connected with Lewis’s amphistome is the existence of a gastric pouch. This structure brings these human Masuri into close relation with the equine parasite which I have named Gastrodiscus Sonsinoii, and which will be found illustrated in this work (fig. [62]). In short, Lewis’s worm appears like a transition form; the absence of gastric supplementary suckerlets separating it from the new generic type.
Bibliography (No. 11).—Lewis, T. R., and McConnell, T. F. P., “Amph. hominis; a new parasite affecting Man,” ‘Proceedings of the Asiatic Society of Bengal,’ Aug., 1876.
Bilharzia hæmatobia, Cobbold.—This remarkable parasite was discovered by Bilharz in 1851. It was subsequently found by myself in an ape (1857); other species of the same genus having since been detected by Sonsino in the ox and sheep (1876). The human examples were originally obtained from the portal system of blood-vessels. Afterwards they were obtained by Bilharz, Griesinger, and others, from the veins of the mesentery and bladder. It was shown that they were not only associated with, but actually gave rise to a formidable and very common disease in Egypt.
In 1864 Dr John Harley made the interesting announcement that he had discovered specimens of this singular genus in a patient from the Cape of Good Hope. He also showed that the entozoon was the cause of the hæmaturia known to be endemic at the Cape. Harley believed his parasites to represent a new species (Distoma capense), but in this view I showed that he was mistaken. His admirable contribution, nevertheless, served not only to establish the wide range of this parasite on the African continent, but also to throw much light upon the subject of endemic helminthiasis. As this worm forms an almost altogether exceptional type of fluke-structure, it became necessary to supersede the original nomenclature proposed by Bilharz and Von Siebold (Distoma hæmatobium). Accordingly I proposed the term Bilharzia, whilst other helminthologists subsequently proposed various titles (Gynæcophorus, Diesing; Schistosoma, Weinland; Thecosoma, Moquin-Tandon). On various grounds, and chiefly on account of priority, most writers have at length definitely accepted the nomenclature which employed the discoverer’s name for generic recognition.
Fig. 7.—The blood fluke (Bilharzia hæmatobia). The lower end of the female is withdrawn from the gynæcophoric canal of the male. After Küchenmeister.
The Bilharzia hæmatobia may be described as a trematode helminth in which the male and female reproductive organs occur in separate individuals; the male being a cylindrical vermiform worm, measuring only half an inch or rather more in length, whilst the female is filiform, longer, and much narrower than the male, being about four fifths of an inch from head to tail; in both, the oral and ventral suckers are placed near each other at the front of the body; in the male the suckers measuring 1/100″, in the female 1/314″ in diameter; in either, the reproductive orifice occurs immediately below the ventral acetabulum. The comparatively short, thick, and flattened body of the male is tuberculated and furnished with a gynæcophoric canal, extending from a point a little below the ventral sucker to the extremity of the tail; this slit-like cavity being formed by the narrowing and bending inwards of the lateral borders of the animal, the right side being more or less completely overlapped by the left margin of the body; caudal extremity pointed; intestine in the form of two simple blind canals. Female with a cylindrical body measuring only 1/312″ of an inch in thickness in front of the oral sucker; lodged in the gynæcophoric canal of the male during the copulatory act; thickness of the body below the ventral acetabulum being about 1/357″, and at the lower part 1/96″; surface almost smooth throughout; intestinal canals reunited after a short separation to form a broad, central, spirally twisted tube extending down the middle of the body; vitelligene and germigene canals combining to form a simple oviducal canal, which is continued into a simple uterine tube, finally opening near the lower margin of the ventral sucker; eggs pointed at one end, or furnished with a projecting spine near the hinder pole.
Fig. 8.—Two eggs of Bilharzia. a, With the yolk coarsely segmented; b, with the yolk granulated and the spine wanting. Original.
The study of the structure and formation of the contents of the ova possesses great interest. When fully developed the eggs are oval, measuring from 1/180″ to 1/160″ in length, with an average transverse diameter of 1/325″. Some are a trifle larger, others smaller. Occasionally one encounters narrow specimens, and also aberrant forms presenting a pear-shaped outline. I have met with eggs not exceeding 1/250″ in their long diameter, and 1/500″ transversely, whose yolk-contents had already arrived at an advanced stage of segmentation.
The shell is transparent, of a brown colour, and free from any markings, lines, or sculpturing. One pole of the shell is invariably narrower than the other, and usually presents a more or less pointed extremity (fig. 8). This narrow end commonly displays a sharp, projecting, beak-like spine, which, at its base, constantly rests upon the centre of the pole of the shell, but occasionally it is eccentrically placed (fig. 8a). In some few examples the spine is removed to a little distance from the actual extremity of the shell; but even in these instances, so far as my observations go, its apex always projects beyond the level of the curved end of the pole. Now and then the spine is altogether absent (fig. 8b); and when present it is, as already hinted, very unequally developed. In size the spine ranges from a mere point, having an extreme length of only 1/8000″, up to the comparatively large magnitude of 1/2500″ lengthways.
According to the best evidence there is no good ground for asserting the existence of any specific differentiation between the parasites coming from the Cape and Egypt respectively.
Fig. 9.—Two eggs of Bilharzia, with eccentrically placed spines. That to the left shows mulberry cleavage of the yolk; the other having lost its embryonal contents by rupture. Original.
Taking a more extended view of the significance of these singular chorional spines, I think we may here recognise the early efforts of Nature, so to speak, to form or evolve a special organ, which, in the eggs of certain other parasites, becomes capable of attaining a relatively prodigious degree of development. To me it seems that the little process in question is a kind of rudimentary holdfast; and, as such, it may be reckoned as the homologue of a variety of egg-appendages. Eleven years ago Mr Edwin Canton discovered some curious ova attached to the conjunctiva of a turtle’s eye. I had no hesitation in pronouncing them to be referable to some ectozoon or entozoon belonging to one or other of the allied genera Polystoma, Tristoma, Octobothrium, and Dactylogyrus. Now, whilst the Bilharzia ova display only a solitary and imperfectly developed holdfast, placed at one end of the shell, the singular eggs described by Mr Canton develop organs of anchorage at both extremities. Parasitic ova exhibiting analogous processes, spines, and filamentary appendages at both poles, have been observed in various species of parasite—as, for example, in Monostoma verrucosum infesting the fox, in Tænia cyathiformis infesting the swallow, in Tænia variabilis of the gambet, in Octobothrium lanceolatum attached to the gills of the common herring; and in Polystoma appendiculata, from the branchiæ of various marine fishes. Eggs of parasites which, like Bilharzia, are furnished with a single appendage, may likewise be seen in the ova of different species of Dactylogyrus infesting the gills of the pike. In the more strongly pronounced developments it is easy to perceive how admirably these outgrowths are adapted to the necessities of the different species of parasite to which they are severally referable; and, even in the case of Bilharzia, the trifling amount of anchorage furnished by a projecting point is not absolutely thrown away. The resistance will also be greater where the spine is situated a little on one side of the pole of the egg, which seems to need steadying during the violent struggles of the embryo to escape from its temporary abode.
When any number of ova are removed from the urine and examined, it will be found that a large proportion of them contain embryos in an advanced stage of larval growth. The structural appearances presented by the embryos whilst still in the eggs are remarkably uniform; since, in all, the yolk appears to have resolved itself into a mass of rounded sarcode-globules, one or two of these particles being conspicuously larger than the rest (fig. [12]). At this stage, except towards the cephalic division of the larva, no tendency to differentiation is perceptible; but some time after the embryo has escaped, one may notice elongated masses of sarcode formed by the coalescence of the globules. Whilst still in the egg, one end of the primitive embryonal mass becomes gradually narrowed, cilia at the same time appearing. This part becomes the future head, eventually acquiring the form of a cowl. Whatever form the body of the embryo may display after extrusion from the shell, the head retains its conical shape, the cone itself being narrowed or widened only when the larva is subjected to abnormal conditions (fig. [14]). Whilst the head is undergoing development within the shell, one, two, or sometimes three, pyriform masses make their appearance within the cone; and after the embryo has escaped, these structures become more marked (fig. 10). The sarcode-globules refract light strongly; and, when the larva is not compressed in any way, they move freely within the somatic cavity. In well-developed embryos, whilst still in the egg, the cilia are observed to clothe every part of the larva except the oral papilla. This minute nipple-like projection measures about the 1/3000 of an inch transversely, forming a very simple kind of unarmed proboscis. When the head of the free embryo is viewed from above, the proboscis looks like a central ring surrounded by a series of regular folds, which radiate outwards like the spokes of a wheel. The ridges thus formed support numerous cilia, these latter projecting at the circumferential margin of the cephalic cone in such a way as to present the figure of a star. Dr Harley has admirably represented this character, which is shared by many other parasitic larvæ. Throughout the greater part of the time, whilst the embryo is still resident within the egg, the broad neck or base of the cephalic cone forms a fixed point of resistance by its firm attachment to the inner wall of the shell; and this structural union, so long as it remains intact, enables the embryo to move not only its head and body from side to side synchronously, but also each part independently. When the time for final escape is drawing near, the vigorous movements of the cone-shaped head seem chiefly concerned in loosening the membranous connection just referred to; and when, at length, the ciliated animalcule has succeeded in overcoming this first difficulty, it is ludicrous to witness its frantic efforts to find an opening in the shell. While thus partially liberated, it will rush to and fro from one pole of the egg to the other, performing a series of summersaults, and at the same time occasionally rolling itself over laterally. This activity becomes gradually more and more violent, until at length its excitement is worked up into a sort of frenzy. I have many times watched these performances, which, however, are only to be seen within those ova whose shells, for some reason or other, refuse to yield to the earlier and ordinary efforts of the prisoner. In all cases where these phenomena are witnessed the eye readily detects a number of small free globules between the embryo and the inner wall of the shell (fig. [13]). These minute particles are likewise tossed about tumultuously during the rapid rotatory movements of the imprisoned larva. Except as regards their size, these globules do not differ in character from the sarcodic contents of the animalcule. They are probably superfluous detachments from the primitive yolk-mass, but it is possible that they may afford some aid in the final breaking up of the shell. Whilst the embryo remains fixed its tail is usually directed towards the narrower or spine-bearing pole of the egg, but in a few instances I have seen this position reversed. As regards the precise mode of emerging from the shell, and the time occupied by the larva in freeing itself, there are several points of interest. Speaking generally, the purer the medium into which the ova are transferred, the more rapid will be the movements of the larvæ. To give an example of observed facts in relation to the rapidity of development, I cite the following:—“On the 20th of August, 1870, I placed twelve eggs of Bilharzia under the microscope. The medium in which they were immersed consisted of eight parts of ordinary drinking water to one of urine. At the expiration of seventeen minutes the first-born made its escape. In the course of another minute two more emerged. In twenty-six minutes the fourth, in twenty-eight the fifth, in thirty-two the sixth, in thirty-four the seventh, in thirty-seven the eighth, in thirty-eight the ninth, in forty the tenth, in forty-three the eleventh, and in forty-six minutes the twelfth, respectively made their appearance.”
Now, this rapid mode of birth and emergence from the shell is very much more striking in the case of eggs which are placed in perfectly pure water; for, whilst the eggs are still in the urine, there appears to be neither the power nor the inclination on the part of the embryo to escape; but, on isolating and placing them in suitable conditions, their behaviour is even more remarkable. In a space of less than two minutes I have repeatedly seen the hitherto motionless embryo alter its shape by contractions, become violently agitated, and burst out of its shell in the condition of a free-swimming animalcule. Moreover, it is worthy of remark that the eggs and larvæ of Bilharzia soon perish in stale urine. “On the 16th of August, 1870, I placed about a thousand eggs in a quart of fountain-water, to which only a drachm or rather less of urine had been added. At the expiration of forty-eight hours not a single living embryo could be found. I subsequently ascertained that I could not keep the embryos alive for twenty-four hours in any water in which I had introduced the smallest trace of mucus, blood-corpuscles, urinary crystals, or decomposing matters of any kind. All sorts of reagents speedily killed the larvæ. Mere discoloration by carmine solution, or by the addition of a drop of the solution of permanganate of potash, instantly caused them to assume grotesque and unnatural shapes (figs. 13 and 14), death sooner or later following as a result of the disintegration and resolution of their delicate bodies into mere sarcode-masses. Still more rapidly poisonous effects were produced by the addition of a little sherry or alcohol. In solutions where the amount of spirit did not exceed one part of spirit, proof strength, to fifty parts of water the effect was the same.”
The development of the larva is equally well accomplished in distilled water, in well-water, and in brackish water. In pure sea-water the process goes on less satisfactorily. It was found, indeed, that the addition of slightly saline water to ciliated embryos, which were on the point of expiring in fresh water, had the effect of reviving them for a time. These facts have an important practical bearing.
I have thus shown that the escape of the embryo is by no means the slow process that Bilharz has described. Almost invariably the shell bursts by a longitudinal slit extending over fully two thirds of its long diameter, the first point of rupture being commonly situated midway between the spine and the centre of the shell. In normal births, so to speak, the head of the animalcule emerges first; but occasionally the animal escapes sideways, and I have even seen the embryo extricate itself tail foremost. Not unfrequently it has a difficulty in detaching itself from the shell, in which case the egg is whirled round and round by the half-freed prisoner (fig. [15]). The lodgment of the spine, however, against any foreign substance affords the necessary leverage for ensuring escape.
The larva never displays its proper elongated, spindle-shaped, or cylindro-conical figure, until some short time after its escape from the shell; and, as a consequence of this, its powers of locomotion are less marked at first than they are subsequently. At the time of extrusion the larvæ are commonly more or less hour-glass shaped (fig. [11]); this particular form being sometimes retained for many minutes or even for an hour. Usually the larvæ have a tendency to acquire their normal shape immediately after quitting the shell; the oval, pear-shaped, and variously contracted forms gradually merging into the characteristic cone-shaped animalcule (fig. [10]). In their fully developed condition, they exhibit the most lively movements; and to witness several hundreds of them rushing about with unceasing activity is a curious sight. The phenomenon, moreover, loses none of its interest from the consideration that only a few hours, or it may have been minutes, previously, these now actively gyrating animalcules were lodged in ovo within the blood-vessels of their human host. From persons who are infested, myriads of these eggs of Bilharzia daily make their escape during the act of micturition; and, when this act is accomplished by the host out-of-doors, it is easy to perceive how readily the ova may be subjected to conditions favorable to the development of larvæ. The direct passage of the urine into any considerable receptacle of natural or fresh water would in a few minutes ensure the hatching of all the eggs; and in the absence of any such direct aid to development, the accidental occurrence of a shower of rain would, in all localities where the Bilharzia disease is endemic, readily transfer the ova into ditches, ponds, rivers, lakes, and ultimately, perhaps, even into the sea itself.
The behaviour of the embryo under the action of reagents of various kinds is remarkable. Thus, when on the 5th of Sept., 1870, I placed some ova in brackish water, of the strength of two parts of fresh water to one of pure sea-water, their contents were readily developed, though the escaping embryos did not swim vigorously. When again I placed some other eggs in pure sea-water, their contained embryos became instantly transfixed, the vibratile cilia of the head being rigid and motionless. At first I naturally concluded that the embryos were killed outright; but, to my great surprise, the shock passed away in about half an hour, when they revived and were soon afterwards hatched. One of the larvæ thus set free carried off several of the loose intra-chorional globules which had, during the period of transfixion, become firmly adherent to the ends of the caudal cilia. Here I may remark upon a decided difference observable between the cilia of the head and body respectively. The former are at all times vibratile, active, and conspicuous, whilst the latter are more delicate, capable of comparatively little motion, and partaking more of the character of fine setæ. In length their general measurement varies from 1/2500″ to 1/2000″. The action of pure sea-water on the free animalcules, previously immersed in fresh or brackish water, was equally striking. All, without exception, immediately became paralysed and almost motionless; nevertheless, on again adding fresh water, several entirely recovered. It is worthy of notice that in these cases the cephalic cilia furnished the first indications of returning viability. I was particularly struck with the behaviour of one embryo, which, under the stimulus of the sudden shock, retracted its cone-shaped head almost entirely within the general cavity of the body (fig. [14], lower specimen). In their moribund condition, whatever shape the embryo retained, the sarcodic contents gradually faded away; the outline of the creature, however, becoming more marked (fig. [16]). Usually the body of the animalcule became elongated whilst expiring in sea-water. Under other circumstances the embryo frequently bursts; the sarcodic contents escaping in the form of amœba-like bodies and the cilia retaining their powers of movement long after all traces of the sarcode have disappeared.
Fig. 17.—Ciliated embryo of Fasciola hepatica, showing the so-called eye-spot. After Leuckart.
The larvæ of Bilharzia closely resemble those of Fasciola hepatica, which latter may be appropriately noticed in this place. The ciliated embryo of the common liver fluke has the form of a long cone inverted; the anterior end or head being flatly convex. In the centre is a short proboscis-like papilla destitute of cilia (fig. 17). The general covering of cilia rests on a well-defined granular epidermis; this latter being succeeded by a dense peripheral layer of large nucleated cells, each of them measuring about 1/2500″ in diameter. The epidermis measures 1/6250″ in thickness. In the central mass of parenchyma no internal organs are recognisable, but Leuckart observed indications of a canal which he thought might open at the tail, though the opening itself was not actually visible.
As long as the ciliated covering remains intact the embryo, like other animalcules, displays great activity, whirling round and round on its own axis, and also describing gyrations and circles of different degrees of range in the water, the latter movements being accomplished by bending the body upon itself to a greater or lesser curvature. The embryos of Bilharzia and other infusoria exhibit the same behaviour, and, as Leuckart observes, when these embryos knock against any obstruction, they pause after the blow, as if to consider the nature of the substance they have touched. As in the case of fluke embryos generally, the ciliated covering eventually falls off and the embryo reassumes a more or less oval figure, at the same time changing its swimming mode of progression for the less dignified method of creeping. In the free ciliated condition the embryo of the common liver-fluke measures, according to Leuckart, 1/190″ in length, the anterior broad end being 1/500″. The cilia have a longitudinal measurement of 1/1388″.
Fig. 18.—Ciliated embryo of Distoma lanceolatum. After Leuckart.
According to the observations of Dr Willemoes-Suhm, the cilia of the embryos of the Distoma megastoma are limited to the anterior pole of the body. This is also the arrangement, as Leuckart first pointed out, in Distoma lanceolatum (fig. 18). On the other hand, Pagenstecher has shown that the embryos of Distoma cygnoides and Amphistoma (Diplodiscus) subclavatum are ciliated all over, an observation which, as regards the latter species, has been confirmed by Wagener and others. Dr Pagenstecher’s original statement to the effect that “intrachorional germs of trematodes offer no distinctive characters,” must, therefore, in the present state of our knowledge, be accepted as a general conclusion admitting of many exceptions. In the early stages of development the embryo of Distoma lanceolatum occupies the centre of the egg, and according to Leuckart has its conical head invariably directed towards the upper pole of the shell, or, in other words, to that end of the egg which is furnished with a lid-like operculum. Leuckart describes the embryo itself as “finely granular and armed at the tip with a dagger-like spine, which, with the simultaneous displacement of the adjacent granular mass, can be pushed forward and drawn back again.” Besides this so-called cephalic granular mass, there are within the embryonic body two other granular masses widely separated from each other, but occupying the posterior half of the embryo. These Leuckart supposes to be the rudiments of a future brood, to be developed at the time when the free embryo shall have lost its ciliated swimming apparatus, shall have bored its way by means of the cephalic spine into the tissues of a mollusk, and shall have become metamorphosed into a sac-like larva (Nurse, Sporocyst, or Redia, as the case may be). Whatever be the full significance of these internal developments, we have at least satisfactory evidence that the complete and free embryo is a globe-shaped animalcule, having the anterior third or cephalic end of the body covered with cilia, and armed with a central boring spine. In consequence of this limitation of the ciliated covering, its swimming movements are less vivacious than those of the embryo of Fasciola hepatica; it will, therefore, probably take up its residence in a less active host than that chosen by the embryo of Fasciola, selecting one of those mollusks which either move slowly or are prone to keep at the bottom of the water. The mature eggs have a length of 1/625 to 1/555 of an inch, and a breadth of 1/833″. The long diameter of the free embryo varies from 1/990″ to 1/833″, the transverse diameter being 1/1562″. Whilst the embryos were still in the egg Leuckart could see no ciliary motion. With most observers, both the ciliary apparatus and the boring spine appear at this stage to have altogether escaped observation.
Fig. 19.—Outline representation of a ciliated embryo of Bilharzia, showing the arrangement of the water vessels and the vacuoles. Original.
As regards the intimate structure of the ciliated embryo of Bilharzia hæmatobia, I have further to observe that, shortly after its extrusion from the shell, the hitherto loose, globular sarcode particles coalesce. This is apparently a preliminary step towards the subsequent differentiation process. Respecting the pedunculated blind sacs formed within the head, I think that we must regard the largest one as representing the stomach of the larva in its future cercarian stage. Under the 1/12″ objective I distinctly recognised, in the cavity of the central blind sac, numerous highly refracting granules, the diameter of which averaged not more than 1/12000″. The rudimentary stomach is often traceable whilst the larva is still within the egg. It measures about 1/500″ in length, including the peduncle, and 1/14000″ in breadth. The width of the narrow stalk does not exceed 1/9000″. The other two-stalked bodies appeared to have the character of lemnisci. They were occasionally well seen whilst the embryo was still within the egg. As regards the integument, it is easy to recognise two layers. In careful adjustments of the focus the inner wall of the transparent dermis presents a beaded appearance. These minute and regular markings do not undergo alteration during the contractions of the body of the larva.
A highly developed water-vascular system exists in these little animalcules. On many occasions I saw traces of this set of vessels, and in several instances I obtained a most satisfactory view of the entire series of branches. Anxious to receive confirmation of my discovery, I demonstrated the existence of these vessels to a skilled microscopist—the late Mr J. G. Pilcher, of H. M. Army. In the briefest terms it may be said that the water-vascular system of Bilharzia, in the larval condition, consists of two main stems, which pursue a tortuous passage from head to tail, and which, in the course of their windings, give off several anastomosing branches (fig. 19). As also obtains in the corresponding larvæ of Diplodiscus subclavatus, there is no excretory outlet visible at the tail.
Encouraged by the experiences and determinations of Pagenstecher, Filippi, Wagener, Leuckart, and others, I sought for the intermediate hosts amongst fresh-water mollusks and small crustacea. Failing of success in these, it occurred to me that the larvæ of Bilharzia might normally reside in fluviatile or even in marine fishes. This latter idea seems also to have struck Dr Aitken. In an appendix to his ‘Report to the Army Medical Department for 1868,’ dated from Netley, Nov., 1869, he gives a figure of a nurse-form, which he terms a cercaria, from the tail of a haddock—suggesting for Bilharzia some genetic relation. Dr Aitken also extends his views in reference to certain larval trematodes alleged to have been found in the so-called Delhi boils and Lahore sores. These parasitic forms have, however, been shown by Dr Joseph Fleming to be nothing more than altered hair-bulbs (‘Army Med. Reports,’ 1868–69).
In regard to the flukes from the haddock, I have satisfied myself that these immature trematodes from the nerves of the cod-tribe can have no genetic relation with Bilharzia; and I think it due to Dr Maddox to say that I accept his conclusion respecting them. In his paper (‘Micros. Trans.,’ vol. xv, 1867, p. 87) he offers strong proof that the so-called Distoma neuronaii Monroii of the haddock (Morrhua æglefinus) is the juvenile condition of Gasterostoma gracilescens of the angler (Lophius piscatorius).
I am sorry to have to state that all my experiments proved negative. I tried to induce the ciliated embryos to enter the bodies of a variety of animals, such as Gammari, Dipterous larvæ, Entomostraca, Lymnæi, Paludinæ, different species of Planorbis, and other mollusks; but neither in these, nor in Sticklebacks, Roach, Gudgeon, or Carp, did they seem inclined to take up their abode.
The very peculiar and formidable helminthiasis produced by this parasite has been thoroughly investigated by Griesinger and Bilharz, and it has been fully described in the standard works of Küchenmeister and Leuckart. My own case from Natal also supplied many interesting clinical facts which were published in my ‘Lectures on Helminthology,’ quoted below. The comparative prevalence of this disorder in Egypt is well established. Symptomatically, its principal feature consists in a general disturbance of the uropoietic functions. Diarrhœa and hæmaturia occur in advanced stages of the complaint, being also frequently associated with the so-called Egyptian chlorosis, colicky pains, anæmia, and great prostration of the vital powers. The true source of the disorder, however, is easily overlooked unless a careful microscopic examination be made of the urine and other evacuations. If blood be mixed with these, and there also be a large escape of mucus, a minute inspection of the excreta will scarcely fail to reveal the presence of the characteristic ova of Bilharzia. Besides the increase of mucus secretion, there may even be an escape of purulent matter, showing that the disorder has far advanced. The patient’s constitution eventually becomes undermined; pneumonia often sets in, and death finally ensues. On making post-mortem examinations the following pathological facts come to light. In cases where the disease has not advanced very far, minute patches of blood-extravasation present themselves at the mucous surface of the bladder, but in more strongly pronounced cases the patches are larger or even confluent. In some instances there are villous or fungus-like thickenings, ulceration and separation of portions of the mucous membrane, with varying degrees of coloration, according to the amount of the extravasation, which becomes converted into grey, rusty-brown, or black pigment deposits. A gritty or sandy deposit is often superimposed, consisting of ordinary lithic-acid grains mixed with eggs and egg-shells. Eggs are readily detected in the urine, these having escaped from the ruptured vesical vessels. The lining membranes of the ureters and renal cavities are also more or less affected; the kidneys being frequently enlarged and congested. It must, however, be borne in mind that in all these organs the true seat of the disorder is the blood, which forms the proper habitat of the Bilharzia; and this being the case, the worms as well as their escaped eggs may be found in any of the vessels supplying the diseased organs. In one instance, quoted by Leuckart, Griesinger found a number of empty eggs in the left ventricle of the heart, and from this circumstance it was supposed that they might be carried into various important organs, or even plug up the larger vessels. As before stated, however, the parasites are more particularly prevalent in the vessels of the bladder, mesentery, and portal system. The effects upon the intestinal mucous membrane are, in most respects, similar to those occurring in the urinary organs. Blood extravasations, with thickening, exudation, ulceration, and fungoid projections, appear in and upon the intestinal mucous and submucous tissues; these appearances, of course, being more or less strongly marked according to the degree of infection.
In regard to the treatment of the helminthiasis, I am precluded from entering into details here; nevertheless, I am glad to perceive that the principles which I long ago enunciated have received approval both at home and abroad. As stated in my ‘Lectures’ our object should be not to interfere with, but to promote nature’s curative efforts. If I read the pathological facts correctly, she seeks to bring about this result by erecting artificial barriers which serve to moderate the bleeding. In this way, under ordinary circumstances, the life of the bearer is sustained, or held in the balance until the parasites either perish or cease to be capable of causing active disease. Depend upon it, this is the principle which should guide physicians in their treatment of the Bilharzia disorder. If the adult parasite were merely attached to the lining membrane of the bladder, then powerful diuretics and medicated injections would probably prove serviceable; but since the entozoa reside in the blood we must be careful not to increase the patient’s troubles. In the case of intestinal worms the most powerful parasiticides may be prescribed without let or hindrance; but that drug must be a truly subtle worm-poison which, when taken into the system, shall kill the blood-flukes without exerting any injurious effects upon the parasite bearer.
When, in 1872, I published my lectures on helminthology, I remarked that it was not improbable that, ere long, many more cases of Bilharzia disease would be brought to light. What has been added in this respect is chiefly due to the researches of Sonsino, but a case of some interest has been recorded comparatively recently by Dr W. K. Hatch, stationed at Bombay. From the particulars furnished it seems evident that the victim, an English gentleman, contracted the disease by drinking water, either in Arabia or in Egypt, in which latter country, however, he had only sojourned fifteen days. From the patient’s statements it appears that, hæmaturia is frequent amongst the Arabs. Incidentally, Dr Hatch mentions that Dr Vandyke Carter had informed him that, so early as the year 1862, he (Dr Carter) had detected the embryos of Bilharzia in the urine of an African boy admitted to the Jamsetjee Jejeebhoy Hospital. The treatment employed by Dr Hatch was that recommended by Dr Harley in his well-known memoir. Having myself energetically opposed Dr Harley’s views on pathological grounds, I am not surprised to see it stated that Dr Harley’s method of treatment effected “no diminution in the number of the parasites.” As I said in my lectures (now out of print) it is evident that “nature” in view of moderating the hæmaturia—by the formation of plugs at the ulcerated points of the mucous surface—sets up the artificial barriers above referred to; therefore if you catheterise and employ medicated injections you do more harm than good. As to the administration of belladonna internally, in view of retarding development, or of destroying the parasite, no good can be expected from this source. I certainly obtained better results with buchu and bearberry (Arctostaphylos).
In the matter of sanitation it is quite evident, from the foregoing data, that the danger of infection cannot arise from the drinking of impure water, as ordinarily understood. The embryonal larvæ would be killed by an admixture of sewage. It is obvious that infection can only occur from swallowing free cercariæ or freshwater mollusks which contain the higher larval forms in their encysted or pupa condition. Slow running streams or stagnant pools with sedgy banks are eminently favorable to the existence and multiplication of intermediary bearers, and consequently their waters are dangerous if employed for drinking purposes.
Bibliography (No. 12).—Bilharz, in Siebold and Köll., ‘Zeitsch. für wissensch. Zool.,’ iv, 1851.—Idem, ‘Wiener medic. Wochenschrift,’ 1856.—Cobbold, T. S., “On some new forms of Entozoa (Bilharzia magna),” ‘Linn. Trans.,’ vol. xxii, p. 364, 1859.—Idem, “Synopsis of the Distomidæ,” in ‘Proceed. Linn. Soc.,’ vol. v, Zool. Div., p. 31, 1860.—Idem, “Remarks on Dr J. Harley’s Distoma capense,” in ‘Lancet,’ also in the ‘Veterinarian,’ and in ‘Intell. Observer’ for Feb. and March, 1864.—Idem, “Entozoa,” l. c., p. 197, 1864.—Idem, “On Blood Worms,” Lecture xx in ‘Worms,’ l. c., p. 145 et seq., 1872; Tommasi’s edit., Vermi, p. 141, 1873.—Idem, “On the Embryos of Bilharzia,” ‘Brit. Assoc. Rep.,’ 1864.—Idem, “On the Development of Bilharzia hæmatobia, together with Remarks on the Ova of another Urinary Parasite occurring in a case of Hæmaturia from Natal,” ‘Brit. Med. Journ.,’ July, 1872; repr. in the ‘Veterinarian,’ 1872.—Idem, ‘New Entozootic Malady, &c.’ (brochure), London, 1865.—Idem, “Helminthes,” in Gunther’s ‘Record of Zool. Literature,’ p. 617, 1865.—Idem, “Entozoa in relation to Public Health and the Sewage Question,” Rep. of the Proceed. of the Metrop. Assoc. of Officers of Health, in ‘Med. Times and Gazette,’ Jan., 1871, repr. in the ‘Veterinarian,’ p. 359, 1871.—Idem, “Verification of recent Hæmatozoal Discoveries in Australia and Egypt,” ‘Brit. Med. Journ.,’ June, 1876.—Idem, “On Sewage and Parasites, especially in relation to the Dispersion and Vitality of the Germs of Entozoa,” rep. in ‘Med. Times and Gaz.’ for Feb., and the ‘Veterinarian’ for May, 1871.—Davaine, C., l. c., ‘Synops,’ and p. 312, 1860.—Diesing, C. M., ‘Revis. d. Myzelmith,’ Vienna, 1858.—Griesinger, “Klin. und Anat. Beobachtungen über die Krankheiten von Egypten,” in ‘Arch. für physiol. Heilkunde,’ 1856.—Idem, ‘Gesammelte Abhandlungen,’ Berlin, 1872.—Idem, ‘Arch. d. Heilk.,’ 1866.—Harley, J., ‘On the Hæmaturia of the Cape of Good Hope, produced by a Distoma,’ rep. in ‘Lancet,’ and ‘Med. Times and Gaz.,’ Feb., 1864; also in Ranking’s ‘Abstract,’ p. 173, 1864, and fully in ‘Medico-Chirurg. Trans.,’ 1865.—Idem, “On the Endemic Hæmaturia of the South Eastern Coast of Africa,” ‘Med.-Chir. Trans.,’ vol. liv, 1871.—Idem, in Hooper’s ‘Vade Mecum,’ 1869.—Hatch, W. K., “Case of Bilharzia hæmatobia,” in ‘British Medical Journal,’ Dec. 14, 1878, p. 875.—Küchenmeister, F., ‘Parasiten,’ 1855; Eng. edit., p. 277, 1857.—Leuckart, R., l. c., s. 617, 1863.—Sonsino, P., “Richerche intorno alla Bilharzia hæmatobia in relazione colla Ematuria Endemica dell’ Egitto e nota intorno un Nematoideo trovato nel Sangue Umano,” ‘Estr. dal Rend., del. R. Accad.,’ 1874.—Idem, ‘Della Bilharzia hæmatobia e delle alterazione Anatomo-patologiche che induce nell’ Organismo Umano, loro importanza come Fattori della Morbilità e Mortalità in Egitto, con cenno sopra una Larva d’Insetto Parassita dell’ Uomo. Estratto dall’ Imparziale,’ Firenze, 1876.—Idem, ‘Sugli ematozoi come contributo alla Fauna Entozooca Egiziana,’ Cairo, 1877.—Idem, “La Bilharzia hæmatobia, et son rôle Pathologique en Egypte,” ‘Arch. Gén. de Médicine,’ for June, p. 650, 1876.—Idem, “Intorno ad un nuovo Parassita del bue (Bilharzia bovis),” ‘Estr. dal Rend. del. R. Accad. di Napoli,’ 1876.—Weinland, D. F., l. c., p. 67, 1858.