PAEASITES, PAKASITES; A TREATISE ON THE ENTOZOA OF MAN AND ANIMALS, INCLUDING SOME ACCOUNT OF THE ECTOZOA. T. SPENCER COBBOLD, M.D., F.R.S., F.L.S., HONORARY VICE-PRESIDENT OP THE BIRMINGHAM NATURAL HISTORY AND MICROSCOPICAL SOCIETY. LONDON : J. & A. CHUECHILL, NEW BUBLINGTON STEEET. BIOLOGY LIBRARY G PREFACE MY introductory treatise on the Entozoa having long been out of print, it occurred to me that instead of attempting another edition it would be better to write an entirely new work, employing only such fragmentary portions of the old treatise as would harmonise with the far wider design I have now in view. Whilst, therefore, I have freely utilised a selection of the illustrations given in the elementary volume, comparatively few of its pages have been incorporated in the present work. Dealing with parasites and parasitism after a manner not hitherto attempted I have purposely omitted minute anatomical descriptions, and, with rare exceptions, I have avoided the introduction of clinical details. While bringing to a focus the records of, and principal references to, a widely scattered, intri- cate, and voluminous literature, it has been my chief endeavour to supply abundance of original matter of a kind that cannot be found in the columns of any existing treatise. Whether I have succeeded or not the experienced helminthologist alone can judge. He, at all events, will perceive that the summary, though compressed within the space of a moderate-sized octavo, can only have resulted from sustained effort. This treatise is not professional, that is to say, it does not concern itself with therapeutics or the curative treatment of parasitic affections; yet it introduces and helps to solve VI PREFACE many questions relating to epidemics, endemics, and epizootics due to parasites. The medical man who only looks at the phenomena of parasitism as displayed within the human terri- tory must of necessity acquire a cramped, narrow, and distorted conception of the role played by parasites in the production of disease. Let it be freely granted that to the practising physician, as such, it matters little how many beasts, birds, reptiles, or fishes perish annually from parasitic affections ; yet, when it is demonstrable that a large proportion of the strictly human entozoa require a change of hosts or, in other words, need to pass through the bodies of the lower animals then it is evident that some acquaintance on his part with the entozoa infesting animals becomes a practical necessity. Knowledge of the kind here offered will often materially aid him in recom- mending prophylactic measures. Moreover, the study of comparative pathology, almost ignored in England, conveys with it other lessons of high value in relation to the healing art. The great mind of John Hunter comprehended all this long ago, as any student of the beautiful preparations contained in the museum of the Royal College of Surgeons may readily convince himself ; and this is all the more noteworthy, since the subject concerns the physician rather than the surgeon. To the naturalist the second half of this book addresses itself in a very direct manner. When engaged in his dissec- tions, an appeal to its pages will often enable him to decide at once as to the species of parasite accidentally encountered, and if a full diagnosis be demanded it will guide him to better sources of information. Many hundreds of correspondents, not having ready access to the systematic writings of Rudolphi, Diesing, and Dujardin, have requested me to identify their te finds." I have rarely or never failed to comply with their requests ; but it is hoped that the present work may prove of ready service to subsequent inquirers, and thus place a reasonable limit upon the number of future applicants. Since the manuscript of this work was completed I have received Dr von Linstow's Compendium PEE FACE Vll der Helminthologie, which, for the purposes held in view by the author, leaves little to be desired. Expressly to meet the requirements of the Sanitarian I have dwelt upon the developmental phenomena exhibited by those parasites that occasion fatal helminthiases ; and, in this relation, I have not confined my remarks to the parasites that are injurious to man in a direct manner, but have extended my observations to the genesis of those entozoa that prove destruc- tive to horses, to beasts of burden generally, and to other creatures which, like cats and dogs, are in various ways sub- servient to man's wants. It will be seen that in this way several questions relating to the purity of water and flesh- food, respectively, have been incidentally brought under notice. In view of the magnitude of the task which my enthusiasm, perhaps unwarrantable, has led me to undertake, I know full well how considerately my foreign friends and correspondents will deal with the errors of omission and commission that they will certainly detect in these pages. If there be any educated persons at home who still affect to despise the revelations of helminthology, I can assure them that their prejudices are misplaced. The study of the structure and economy of a humble parasite brings to the investigator no slight insight into the workings of nature. If these workings cannot at all times be pronounced to be " good and beautiful," they must at least be characterised as " true." The knowledge of the true especially if that knowledge by its practical applications be calculated to confer substantial benefits upon man and his inferior fellow- creatures ought to be held in high esteem; but, apart from this purely utilitarian view, there remains for the investigator the delight occasioned by the in-rush of new scientific ideas. The average mind, being either essentially commercial or ridiculously sentimental, as the case may be, is totally inca- pable of comprehending the motive power that animates and guides the votary of science. The late Professor Faraday, a Vlll PREFACE man wholly untinged by the ambitions of wealth and power, once remarked to me that there were no people so difficult to instruct as those who were ignorant of their own ignorance. It is just these very persons who, when placed in high positions of social, political, or professional trust, most powerfully con- tribute to check a nation's progress. There are too few genuine workers at science in this country. As one of the rank and file, I claim only to have honestly contributed my mite. I should like to see a small army of helminthologists rise up and lay siege to the fortresses at present securely held by thousands of death-dealing parasites. T. S. C. 74, PORTSDOWN ROAD, LONDON May, 1879. SYNOPSIS OF CONTENTS. PAGE GENERAL INTRODUCTION 1 BOOK I. PARASITES OF MAN. SECTION I. TREMATODA (FLUKES) . . . .14 II. CESTODA (TAPEWORMS) . . . .56 III. NEMATODA (ROUNDWORMS AND THREADWORMS) . 149 IV- PART I. Acanthocephala (Thornheaded Worms) . 256 II. Suctoria (Leeches) .... 257 III. Arachnida (Parasitic forms of) . . 259 IV. Crustacea (alleged Parasitic forms of) . 268 V. Insecta (Parasitic forms of) . . . 269 VI. Protozoa (Parasitic forms of) . . 2.7&- APPENDIX (Statistics) . . . . .284 BOOK II. PARASITES OF ANIMALS. SECTION I. PARASITES OF MAMMALIA. PART I. Parasites of Quadrumana . . . 289 II. Parasites of Cheiroptera . . . 293 III. Parasites of Insectivora . . . 295 IV. Parasites of Carnivora . . . 297 V. Parasites of Pinnipedia . . . 313 VI. Parasites of Rodentia . . . 315 VII. Parasites of Edentata . . .320 VIII. Parasites of Ruminantia . . . 322 IX. Parasites of Solidungula . . . 356 X. Parasites of Pachydermata . . .393 XI. Parasites of Cetacea and Sirenia . . 416 XII. Parasites of Marsupialia and Monotremata . 430 II. PARASITES OF AVES .... 434 ,, III. PARASITES OF REPTILIA . . . 451 IV. PARASITES OF PISCES .... 457 V. PARASITES OF EVERTEBRATA . . . 480 APPENDIX (Hsematozoa) ..... 485 INDEX 489 LIST OF BIBLIOGRAPHIES. PAGE No. 1. General and systematic treatises . . .8 2. Minor treatises, general memoirs, and monographs . 10 3. Literature of Fasciola hepatica in man . . .17 4. Distoma lanceolatum in man . . . .20 5. crassum _, . . . .28 6. sinense . . . . .29 7. conjunctum in man . . . .33 8. heterophyes . . . . .35 9. ophthalmobium . . . .36 10. Tetrastoma and Hexathyridium . . . .36 11. Amphistoma hominis . . . . .38 12. Bilharzia hcBmatobia . . . . .55 13. Thl> of this fluke must be armed cercaria6, otherwise they could not have bored their way through the human skin. As we shall see, Dr Willemoes-SuhnVs 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 K 17, 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 de- scribed under the combined generic and specific name of TREMATODA 15 Distoma hcpaticum ; but the title is both incorrect and inappro- priate. The proper generic appellation of this parasite is Fasciola, as first proposed by the illustrious Linneus (1767) and subsequently adopted by F. Miiller (1787), Brera (1811), Ram- dohr (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 con- tinually 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 reach- ing an entire inch or even sixteen lines ; its greatest breadth also varying from half an inch to seven or eight lines trans- versely j 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 ; intromit- tent 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 re- productive organs, being bordered on either side and below by a continuous dark band, indicating the position of the so-called yelk-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 16 PARASITES OF MAN to furnish full descriptions of the commoner kinds of par&sfte, 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 else- where 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 f Boston Medical and Surgical Journal ' for the years 1852-53-54, Dr J. X. Chabert described several cases of Taenia, and he averred that the tapeworms were associated with numerous specimens of Distoma hepaticum. The passage of dis- tomes by patients during life was even regarded by Dr Chabert as indicative of the presence of Taenia 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 Taenia " in a boy four and a half years old, given in the 49th vol. of the journal, Dr Chabert writes as follows : " In con- sequence of his passing the Distoma hepaticum, I concluded he must be afflicted with Taenia." Further on it is added, that the administration of an astringent injection " caused the dis- charge 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. Not- TREMATODA 17 withstanding this successful treatment the haamatemesis returned in about a month, when, finally, three more flukes were vomited and the bleeding ceased. Had not the parasites been sub- mitted for identification to a competent observer (Prof. Martins, of Montpellier), some doubt might have been enter- tained as to the genuineness of this remarkable case. In refer- ence 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. BIBLIOGEAPHY (No. 3). Full references to details of the cases fyy Partridge, Fox, and Harris are given in Appendix B. to Lankester's Edit, of Kuchenmeister 3 s Manual. See also the works of Davaine and Leuckart (I. c. Bibl. No. 1). Carter, H. V. f " Note on Distoma hepaticum " (from a patient under the care of Mr Pandoorung), f 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 hepatique chez Fhomme ; in ' Gazette des Hopitaux ' for December, 1878 (p. 1147). For further references in this work, see Bibliog. No. 49. Distoma lanceolatiim, 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 Kiichner, who obtained forty-seven specimens from a girl in Bohemia. Probably many similar instances have been over- looked, and Kiichenmeister 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 larvae 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, measur- ing rather more than the third of an inch in length, and about one line and a half in breadth, being also especially charac- terised 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 2 18 PARASITES OF MAN 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 imme- diately in front of the ventral sucker, and below the point at which the in- testine bifurcates ; the oral sucker is nearly terminal, and ^" 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, form- ing 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 caudate commu- nicates 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 oesophageal bulb, oppo- site 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 : FIG. 1. The lancet-shaped fluke (Distoma lanceolatvm), showing the disposition of the digestive and reproductive organs inter- nally. Viewed from behind ; mag. about 12 diameters. After Blan- chard. TREMATOUA 19 " 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 sup- plied by ten little stagnant pools. These reservoirs harboured numerous amphibia and mollusks (such as Lymnaus and Palu- dina), 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 de- clined. 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 sub- jected) 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 y 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 larvse, 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 larvae of Distoma lanceolatum have not been observed. The Planorlis marginatus has been confidently referred to as the intermediate bearer of the cercariae of the common fluke, and Leuckart supposes that the same mollusk harbours the larvee of this species. The ciliated embryos carry a boring 20 PARASITES OF MAN spine or tooth, and it is most probable that the higher larvae are similarly armed. BIBLIOGRAPHY (No. 4). Kichner (see Leucltart) , quoted above. Cobbold, 'Entozoa' (p. 187). The case byBucholz (reported as one of Fasciola hepatica) is given by Jordens in his work (quoted by Diesing and Leuckart) f Entomologie und Helmin- thologie des menschlichen Korpers ' (s. 64, tab. vii, fig. 14), 1802. Chabertfs French case is quoted by Rudolphi in his ' Ento- zoorum 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 con- tained in the Museum of the Royal College of Surgeong. 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 1804; 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 Distomidas," p. 5, 'Proceedings,' vol. v). The late Dr Lankester, it is true, was the first to give a dis- tinctive 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 cras- sum to designate a small fluke infesting the house-martin (Eirundo urlica) ; but for reasons similar to those which con- tributed 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 Dicroccelium Buskii. In my judgment there are no sufficient grounds for retaining Dujardin's genus. Further, 1 may TREMATODA 21 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 Greorge Johnson re- specting 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 vege- tables 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 state- ments 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 larvge, 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 ques- tion 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, 1575, 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 diarrhoea, which persisted until 22 PARASITES OF MAN expulsion of some of the parasites had occurred. Accord- ing 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 pre- sence 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 diarrhoea. In both cases there was more or less flatus. The motions were white, and there were other indica- tions 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 faeces, 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 sym- ptoms 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, head- ache, and diarrhoea 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 expul- sion ; and in this view I ordered an aloetic pill followed by a castor-oil emulsion. This having no effect, I subsequently prescribed aloes and assafretida 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 occasion- ally 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 TREMATODA 23 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 compara- tively 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 an4 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 ^". None of the twelve examples that I have examined approach the length of three inches; but Mr Busk assured me that, judging from his recollection, some of his specimens were even longer than that. I fear, nevertheless, that the estimate given in my Synopsis is somewhat exaggerated ; at all events it is so for average specimens. The new anatomical facts made out by me bear reference 24 PARASITES OF MAN 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 ' Intro- duction ' I showed in dotted outline two large organs which I supposed to be the testes. I distinctly ob- served 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 y k). No doubt could be entertained as to the testicular character of the lower organ (k). In the original draw- ing I further indi- cated the presence of a third and much smaller globular mass. Fi z .3. The large human nuke (Jhstoma crassiim). a, Oral sucker ; m b, intestine; c t csecal end of same; d, reproductive papilla; which I termed the e, uterine rosette (the folds of which are not branched) ; / one of the folds (in profile) ; g, vitellarium ; A, hernial protrusion (the Ovary I but what result of an injury to the specimen); i, upper testis-, j, streaks -, or layers of seminal fluid which have escaped by rupture Supposed to represent and assumed a branched appearance , *, lower testis uninjured (but slightly altered in outline from flattening) ; J, ventral sucker. thlS Organ in the Magnified 2 diameters. Original. 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 beauti- fully distinct in one of my specimens, forming the most attrac- TBEMATODA 25 tive 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 reproduc- tive 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 ~", by ^ 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, how- ever, 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 26 PARASITES OF MAN 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 role 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 larvae 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 deternfine the particular species of Ostrea to which the Ningpo oysters should be referred. Mons. Giard is of opinion that the singular larvae 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 larvae when they consumed the Ningpo oysters. Moreover, if it should happen that none of the other larvae 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 Salmonicke 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-larvae. 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-larvae in marine bivalve mollusks. In this connection I will only further observe that we possess TREMATODA 27 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 sym- ptoms, 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 in- vestigation we could be made acquainted with the facts of hel- minthism as they occur amongst the raw-flesh Bnd 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' hears 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 ; more- over, one of their children, a little girl, was also victimised by the same species of fluke. Thus, in one family I have en- countered 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 cha- racters. The Distoma crassum is a large, flat helminth vary- ing 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 28 PARASITES OF MAN 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 'Dis- eases of the Liver/ 2nd edition, quoted by Lankester in Appen- dix B to Kuchenmeister's 'Manual of Parasites/ p. 437, 1857. Cobbold, T. S., " Synopsis of the Distomida," in ' Journ. of the Proceed, of the Linnean Soc./ vol. v, Zool. Div., 18GO (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 mis- sionary 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 McConnelFs paper quoted below (Bibl. No. 6). Leuckart } 1. c., Bd. I, s. 560. Weinland, 1. c. (Bibl. No. 2), Appendix, p. 87. Distoma Sinense, Cobbold. The discovery of this species is due to Prof. J. F. P. McConnell, who " on the 9th of Sept., 1874, found a large number of flukes in the liver of a Chinese, ob- structing the bile ducts." The species measures T 7 5 " in length, by j" in breadth, the eggs being ~ 3 " by ^" . 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 TKEMATODA 2 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 in- terpreted the facts of structure some- what 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 Mac- gregor, chief medical officer of the Colony of Fiji. The post mortem revealed the presence of a very great number of / t 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 re- ceived through Dr Henry Clark, of Glas- gow, two Mauritius specimens, which when compared with the Calcutta exam- ples 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 \ iny/ / _ complete in details, and well illustrated. It is not a little curious to notice thatFi 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 com- mon 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. BIBLIOGEAPHY (No. 6). McConnell, J. F. P., " Remarks on the Anatomy and Pathological relations of a new species of B. 3. The Chinese fluke (Dis- toma Slnense) . a, Oral sucker ; b, cesophageal bulb ; c, intestine ; c 1 , csecal end ; d, ventral sucker ; e, genital pore ; /, uterine folds ; g, ovary ; h, vitellarium ; i, vitelligeue duct; k, upper seminal reservoir; I, testes; m, lower seminal pouch ; o, vas deferens ; p, pulsatile vesi- cle; ', water vessel. After McConnell. 30 PARASITES OF MAN 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. Cofc&oZd, T. S., in a note to the ' Lancet,' Sept., 1875, and in the Appendix to Macgre- gor's paper, p. 15, I3 t 77.Leuckart j R., 1. c., Bd. ii, s. 871, 1876. Distoma conjunction, 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 J" in length, but the majority of those found by McConnell in man were fully |" 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 exa- mining 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" dis- covered 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 follow- ing case." " Jamalli Khan, a Mahoinrnedan, 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 TKEMATODA 31 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 down- wards to nearly the level of the umbilicus ; the lower border of the liver, however, can only just be felt below the ribs. Tem- perature on evening of admission 101 F. Conjunctivas are anaemic, 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) vary- ing 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 evacua- tions 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 ansemic, 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 Ib. 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 contain- ing no parasites, and no ova even could be detected on micro- scopical 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 extra- ordinary had been detected in its condition, but, so far as it could be examined, it was found patent ; the duodenal mucous 32 PARASITES OF MAN membrane was well bile-stained, and there was evidence of biliary colouring matter in the faecal 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 Ibs. 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) faecal 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 choloeinia, 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 TBEMATODA 33 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 I" (three eighths of an inch); average breadth T g". ' 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 uiibranched. Uterine folds and ovary placed in the median line, and above the male generative organs, the latter consist- ing 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 *' ; average breadth j~" '. 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 J"; only two or three specimens of this size were found in this liver, and these showed evidences of immaturity ; a few were also found 4" in length ; but the great majority exactly f ". The ana- tomical 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 geo- graphical 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). Colloid, T. $., " Synopsis of the Distomida3 " (1. c.), 1859; and in "Further Observations on Entozoa, with experiments," 'Linn. Trans.,' vol. xxiii (tab. 33, p. 349), I860. Idem, "List of Entozoa, including Pen- tastomes, from animals dying at the Zool. Soc. Menagerie between the years 1857-60," ' Proceed. Zool. Soc./ 1861. Idem, ' Entozoa/ p. 20, pi. ii, 1864; and in "Manual of the Internal 3 34 PARASITES OF MAN Parasites of our Domesticated Animals/' p. 81, 1873. Lewis, T. R.j and Cunningham, D. D. t in a footnote to their ' Micro- scopical and Physiological Researches/ Appendix C., 'Eighth Ann. Rep. of the San. Comm. with the Govt. of India/ p. 168, Calcutta, I872.McConnell, J. F. P., "On the Distoma con- junctum," 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. Distoma heterophyes, Von Siebold. This minute parasite, measuring only f 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 dis- tributed 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 else- where 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 oesophagus, which divides immediately above the ventral acetabulum ; intestinal tubes simple, gradually widening below and terminating near the posterior end of the body ; repro- ductive 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 super- numerary 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 ' in diameter, and having a thick-lipped margin, which supports seventy fish- TEE MA TOD A 35 FIG. 4. The small Egyptian fluke (Distoma heterophyes), viewed from behind. The large ventral sucker, supple- nieutary disk, uterus, testes, simple divided intestine, vitellarium, and pulsatile vesicle are conspicuous. Original. 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 y^", whilst their breadth was ' '. 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 ordi- nary 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 " hold- fast " 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 oesophagus, 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 ~ f in length by -535" transversely. BIBLIOGRAPHY (No. 8). Bilharz, (< Beitrag zur Helminth, humana," ' Zeitsch. fiir wissenschaftl. Zool./ s. 62, 1851. 36 PARASITES OF MAN Cobbold, 'Entozoa/ p. 195, l864>.Kuchenmeister, F., ' Para- siten/ 1855, s. 210, Eng. edit., p. 276, 1857. Lear ed, " Descrip- tion of Distoma constrictum," f Quarterly Journal of Micros. Science/ new series, vol. ii, 1862. Leuckart, II., 1. c., s. 613, 1863. Moquin-Tandon, on the Genus Fasciola, 1. c., 1861. Weinland, on Dicrocalium, 1. c., p. 86, 1858. Distoma ophthalmobimn, Diesing. There is every reason to believe that the small flukes found by Gescheid and Yon Ammon in the human eye were sexually immature worms, but since it cannot be decided as to what adult species they are referable I pre- fer to notice them under the usual title. Possibly these eye-worms may be referred to D. lanceo- latum, as suggested by Leuckart. However FIG 6. The eye fluke (Dittoma ophtttaimo- that may be, I deem it unnecessary to repeat the binm). Showing the J ' . J f suckers and intestinal details recorded in the treatises quoted below. tubes After Von _,. . Ammon. The largest examples measured only half a line or about one millimetre in length. BIBLIOGRAPHY (No. 9). Cobbold, ' Entozoa/ p. 191. Ges- cheid (D. oculi humani), in Von Ammon' s f Zeitsch. f. Ophth./ iii, and also in Ammon' s ' Klin. Darstell. d. Krankheit d. Menschl. Auges.,' vols. i and iii. Kuchenmeister, Eng. edit., p. 287. Leuckart, 1. c., s. 610. Nordmann (Monostoma lentis), " Mikr. Beitr./' Heft, ii, 'Vorwort/ s. ix, 1832. Tetrastoma renale, Chiaje ; Hexathyridium pinguicola, Treut- ler ; 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 haemoptysis. BIBLIOGRAPHY (No. 10). Delle-Chiaje, 'Elmintografia Umana,' 1833. Bremser (1. c., Bibl. No. 2), s. 265, 1819. Cobbold, ' Entozoa' (p. 204, et seq.).Dujardin (1. c., Bibl. No. 2), s. 265, 1819. Treutler, ' Obs. Path. Anat. ad Helm. Corp. Humani/ p. 19, 1793. Zeder, ( Anleitung zur Naturg. der Ein- geweidewiirmer,' 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 TREMATODA 37 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 Assa- mese. 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 Simp- son, 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, oesophagus ; e, genital pore ; /, vagina ; g, duct us ejaculatorius ; A, ventral nerve cords; i, intestinal canal;.;', upper testis; k, water vessel; I, 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 caecum 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. Ooodeve.) In continuation of their narrative, Drs Lewis and McConnell go on to say that, " with reference to this preparation, the follow- ing very interesting particulars from the ' Annual Jail Eeport of Tirhoot ' for 1857 have been very kindly placed at our disposal by the Surgeon-General, Indian Medical Department. The prisoner, 38 PARASITES OF MAN 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 caecum 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 caecum and ascending colon, none in the small intestines." This description is by Dr Simp- son, 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 contract- ing. Body short and tapering to a blunt point." Drs Lewis and McConnelPs description of the worm is too long to be quoted in full. The parasites measure 3 " to J" in length, by " to j" 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 con- nected 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 Gastro- discus Sonsinoii, and which will be found illustrated in this work (fig. 62). In short, Lewis's worm appears like a transi- tion form ; the absence of gastric supplementary suckerlets separating it from the new generic type. BIBLIOGRAPHY (No. 11). Lewis, T. E., and McConnell, T. F. P., ef Amph. hominis ; a new parasite affecting Man," ' Proceedings of the Asiatic Society of Bengal/ Aug., 1876. Bilharzia htematobia, 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 TKEMATODA 39 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 hcematuria known to be endemic at the Cape. Harley believed his parasites to represent a new species (Diatom a 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 no- menclature proposed by Bilharz and Yon Siebpld (Distoma haematoMum) . Accordingly I proposed the term Bil- harzia, whilst other helminthologists subsequently proposed various titles (Gyntecophorus, Diesing ; . Schistosoma, Weinland; Thecosoma, Moquin-Tandon) . On various grounds, and chiefly on account of priority, most writers have at length definitely accepted the nomen- clature which employed the disco verer's name for generic recognition. The Bilharzia htematobia may be described as a trematode helminth Fl< 7 ._T h eo7 fluke in which the male and female repro- ductive organs occur in separate indi- viduals; 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 Ti ~", in the female ~ f 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 gynceco~ phoric canal, extending from a point a little below the ventral sucker to the extremity of the tail ; this slit-like cavity being heematobia). The lower end of the female is withdrawn from the | cophoric canal of the male. Kiichenmeister. 40 PARASITES OF MAN formed by the narrowing and bending inwards of the lateral borders of the animal, the right side being more or less com- pletely 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 ^ of an inch in thickness in front of the oral sucker; lodged in the gynascophoric canal of the male during the copulatory act ; thickness of the body below the ventral acetabulum being about jjy", and at the lower part 55"; surface almost smooth through- out ; 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. 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 ~g" to jj^" in length, with an average transverse diameter of j^". 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 ~" in their long diameter, and xfi" 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 sculptur- ing. 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 occa- sionally it is eccentrically Fro. 8. Two eggs of Bllharzia. a. With the yolk J J coarsely segmented ; *, with the yolk granulated "and placed (fifiT. 8 d). In SOme few the spine wanting. Original. examples the spine is re- moved to a little distance from the actual extremity of the shell ; but even in these instances, so far as my observations go, TREMATODA 41 its apex always projects beyond the level of the curved end of the pole. Now and then the spine is altogether absent (fig. 8 b) ; 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 soW', up to the comparatively large magnitude of ^^' 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. 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 deve- lopment. To me it seems that the little process in question is a kind of rudi- mentary holdfast ; and, as such, it may be reckoned as the homologue of a variety of egg-appendages. Eleven years ago Mr Ed- win Canton discovered some curious ova attached to the conjunctiva of a turtle's eye. I had no hesitation in pronounc- ing them to be referable to some ectozoon or entozoon belonging to one or other of the allied genera Polystoma, Tristnma, Octobothrium, and Dactylogyrus. Now, whilst the Bilharzia ova display only a solitary and imperfectly deve- loped 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 pro- cesses, 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 Ttenia cyathiformis infesting the swallow, in Taenia variabilis of the gambet, in Octobothrium, lanceolatum attached to the gills of the common herring; and in Polystoma appendiculata, from the branchiee of various marine fishes. Eggs of parasites which, Fro. 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. 42 PARASITES OP MAN like Bilharzia, are furnished with a single appendage, may like- wise be seen in the ova of different species of Dactylogyrus in- festing the gills of the pike. In the more strongly pronounced developments it is easy to perceive how admirably these out- growths 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 steady- ing during the violent struggles of the embryo to escape from its temporary abode. Fio. 10. Free ciliated embryo of Bilharzia, with pear-shaped rudimentary organs below the head. Original. FIG. 11. Two ciliated embryos of Bilharzia; showing sar- code spherules in their interior. That to the lett has recently escaped the shell. Original. 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 struc- tural 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 TREMATODA 43 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 develop- ment within the shell, one, two, or sometimes three, pyri- form 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 5 of an inch transversely, form- ing a very simple kind of unarmed pro- boscis. 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 mar- gin 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 larvaB. 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 FIG. 12. Egg of Bilharzia, with contained embryo and free sarcode globulea. Ori- ginal. 44 PARASITES OF MAN 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 par- tially 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 aud ordinary efforts of the prisoner. In all cases where these phe- nomena 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 pro- bablv superfluous detachments from the pri- mitive yolk-mass, but it is just possible that fa^ may a ff or( J gome a j^ { n ^ Q fi na l break- ing 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 larvae. 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 developed. Original. TREMATODA 45 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, anji burst out of its shell in the condition of a free- swimming animalcule. More- over, it is worthy of remark that the eggs and larvae of Bil- harzia 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 em- bryo could be found. I subse- quently 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 larvae. Mere discolora- tion by carmine solution, or by the addition of a drop of the solu- FlG tion 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 46 PARASITES OF MAN 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 larvae are commonly more or less hour-glass shaped (fig. 11) ; this particular form being some- times retained for many minutes or even for an hour. Usually the Iarv89 have a tendency to acquire their normal shape imme- diately after quitting the shell ; the oval, pear-shaped, and variously contracted forms gradually merging into the charac- teristic cone-shaped animalcule (fig. 10). In their fully devel- oped 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 TBEMATODA 47 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 larvae. 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. FIG. 15, Egg of Bilharzia, with the shell still adhering to the escaped ciliated embryo. Original. FIG 16. Ciliated embryo of Bilharzia in the act of dying from the escape of its sarcodic contents. Original. 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 trans- fixed, 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 larvae 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 48 PARASITES OF MAN 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 setae. In length their general measurement varies from 5" to 5000"' ^ ne a tion 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 reco- vered. 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 circum- stances the embryo frequently bursts ; the sarcodic contents escaping in the form of amoeba-like bodies and the cilia retain- ing their powers of movement long after all traces of the sarcode have disappeared. The larvae of Bilharzia closely resemble those of Fasciola hepatica, which latter may be appro- priately noticed in this place. The ciliated em- bryo 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 53-" in diameter. The epidermis measures g^ D " in thickness. In the central mass of paren- chyma 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 FIG. 17. CiliHted em- bryp of Fasciola he- patica, showing tlie so-called eye-spot. After Leuckart. TBEMATODA 49 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 digni- fied method of creeping. In the free ciliated condition the embryo of the common liver-fluke measures, according to Leuckart, ~" in length, the anterior broad end being ~". The cilia have a longitudinal measurement of -o^" . 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) subdavatum are ciliated all over, an observation which, as regards the latter species, has been confirmed by Wagener and others. Dr Pagens teener's original statement to the effect that " intracho- rional 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 occupy- ing 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 4 50 PARASITES OF MAN 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 FIG. is -ciliated em- vivacious than those of the embryo of Fasciola c2iatl^b a iluc: 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 ^ 5 to ^ of an inch, and a breadth of 5 jj". The long diameter of the free embryo varies from ^ 5 " to g y, the transverse diameter being 7353". 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. A's regards the intimate structure of the ciliated embryo of Bilharzia hamatobia, 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. Respect- ing the pedunculated blind sacs formed within the head, 1 think that we must regard the largest one as representing the stomach of the larva in its future cercarian stage. Under the ' objective I distinctly recognised, in the cavity of the central blind sac, numerous highly refracting granules, the diameter of which averaged not more than y^/'. The rudi- mentary stomach is often traceable whilst the larva is still within the egg. It measures about 5 J 5 " in length, including the peduncle, and ,4 55 " in breadth. The width of the narrow stalk does not exceed ~ 05 ". 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 TREMATODA 51 regular markings do not undergo alteration during the con- tractions 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 larvae 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 crus- tacea. Failing of success in these, it occurred to me that the larvae of Bil- harzia 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 Fr f 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 Ori s inal - 52 PARASITES OF MAN 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 aglefinus) 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 larvae, Entomostraca, Lymnaei, Paludinse, 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 Kiichenmeister 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. Diarrhoaa and haematuria occur in advanced stages of the com- plaint, being also frequently associated with the so-called Egyptian chlorosis, colicky pains, anaemia, and great prostra- tion 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 them- selves at the mucous surface of the bladder, but in more strongly pronounced cases the patches are larger or even TEEMATODA 53 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, accord- ing to the amount of the extravasation, which becomes con- verted 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, Grie- singer 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 pre- cluded 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 patho- logical 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 54 PARASITES OF MAN 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, haematuria is frequent amongst the Arabs. Incidentally, Dr Hatch men- tions 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 haematuria 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 larvae would be killed by an admixture of sewage. TREMATODA 55 It is obvious that infection can only occur from swallowing free cercariae 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 Koll., 'Zeitsch. fiir wissensch. Zool./ iv, 1851. Idem, ' Wiener medic. Wochenschrift/ 1856. Cobbold, T. 8., " On some new forms of Entozoa (Bilharzia magnet)," ' Linn. Trans. / vol. xxii, p. 364, 1859. Idem, ff Synopsis of the Distomidse," 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/' 1. c., p. 197, 1864. Idem, " On Blood Worms," Lecture xx in ' Worms/ 1. c., p. 145 et seq., 1872 ; Tommasi's edit,, Yermi, p. 141, 1873. Idem, " On the Embryos of Bilharzia," ' Brit. Assoc. Rep./ 1864. Idem, " On the Development of Bilharzia hamatobia, together with Remarks on the Ova of another Urinary Parasite occurring in a case of Hgematuria 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, iu 'Med. Times and Gazette/ Jan., 1871, repr. in the 'Veterinarian/ p. 359, 1871. Idem, "Verification of recent Hasmatozoal Discoveries in Australia and Egypt," ' Brit. Med. Journ./ June, 1876. Idem, " On Sewage and Parasites, espe- cially in relation to the Dispersion and Vitality of the Germs of Entozoa," rep. in ' Med. Times and Gaz.' for Feb., and the ' Vete- rinarian' for May, 1871. Davaine, C., 1. c., ' Synops/ and p. 312, 1860. Diesing, C. M., 'Revis. d. Myzelmith/ Vienna, 1858. Griesinger, " Klin, und Anat. Beobachtungen iiber die Krankheiten von Egypten," in ' Arch, fiir physiol. Heilkunde,' 1856. Idem, ' Gesammelte Abhandlungen/ Berlin, 1872. Idem, 'Arch. d. Heilk./ 1866. Harley,J., ' On the Haematuria 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. 1 73, 1864, and fully in ' Medico- Chirurg. 56 PARASITES OF MAN Trans./ 1865. Idem, " On the Endemic Haematuria 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 h&matobia," in 'British Medical Journal/ Dec. 14, 1878, p. 875. Kuchenmeister, F., ' Parasiten/ 1855; Eng. edit., p. 277, 1857. Leuckart, R., 1. c., s. 617, 1863. Sonsino, P., " Richerche intorno alia Bilharzia haematobia in relazione colla Ematuria Endemica delP Egitto e nota intorno un Nematoideo trovato nel Sangue Umano," ' Estr. dal Rend., del. R. Accad./ 1874. Idem, ' Delia Bilharzia haGmatobia e delle alterazione Anatomo-patologiche che induce nell' Organismo Umano, loro importanza come Fattori della Morbilita e Morta- lita in Egitto, con cenno sopra una Larva d'Insetto Parassita dell' Uomo. Estratto dall' Imparziale/ Firenze, 1876. Idem, ' Sugli ematozoi come contribute alia Fauna Entozooca Egi- ziana/ Cairo, 1877. Idem, " La Bilharzia haematobia, et son role Pathologique en Egypte," ' Arch. Gen. de Medicine/ 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., 1. c., p. 67, 1858. SECTION II. CESTODA (Tapeworms). Tania mediocanellata, Kuchenmeister. This cestode is fre- quently spoken of as the unarmed or beef tapeworm. In general appearance it is very similar to the armed form. It is, how- ever, a larger and broader animal, being at the same time rather stouter. It varies usually from fifteen to twenty-three feet in length, but specimens have been described as attaining thirty feet. It is called the unarmed tapeworm in consequence of the absence of any coronet of hooks on the head ; and consequently, also, from there being no prominent rostellum or proboscis. The place of the last-named structure, however, is supplied by a small rudimentary disk, which I have seen protruded on pres- sure (fig. 20). Usually this disk forms a more or less conspicuous cup-shaped circular depression, which has been compared to and described as a fifth sucker. That it is not, in any structural sense, comparable to the true suckers, I have had abundant opportunity of ascertaining ; nevertheless, I do not doubt that it is to a slight extent capable of being used by the parasite as a supernumerary holdfast. The anchorage thus secured, however, is by no means equal to that obtained by the armed species. CESTODA 57 This explains the comparative difficulty we find in procuring a specimen of the armed tapeworm with the head attached. FIG. 20. Head of Tania mcdiocanellata. Showing the calcareous corpuscles, suckers, rudimentary proboscis, and water vessels. Highly magnified. Original. The establishment of this species as distinct from T. solium is due to Kiichenmeister ; but it is curious to observe how accurately this determination was foreshadowed by the shrewd naturalist and theologian, J. A. E. Goeze, who clearly indicated two forms of the common tapeworm, remarking (1. c., Bibl. No. 1, s. 278): "Die erste ist die bekannte grosse, mit langen dicken und gemasteten Gliedern, die ich Tania cucurlitina, grandis, saginata, nennen will." The same author (s. 245) pointed out the resemblance subsisting between the tapeworm of the cat (T. crassicollis) and the vesicles (" Krystallblasen ") and their contained " erbsformige Blasen " (Cysticercus fascio- laris ) of the mouse. Thus the celebrated pastor of St BJasius, in Quedlinberg, almost contemporaneously with Pallas, early 58 PARASITES OF MAX arrived at the conclusion that the hydatid-measle was a kind of tapeworm. Eespecting the organisation of this worm I may observe that the mature joints have a more complicated uterine organ than obtains in Tania solium, presenting nearly double the number of lateral branches. They are more closely packed, running outwardly in an almost parallel manner. The first sexually ma- ture proglottis occurs at about the 450th joint, but whereas, in the pork FIG. 21. Free proglottides of Tatnia mediocanellata. After tapeworm, Onlv SOmC 200 Leuckart. J subsequent segments share this perfect character in the beef tapeworm, according to Leuc- kart, as many as 360 or even 400 mature joints may be present. The joints are very liable to form monstrosities ; these abnor- malities sometimes affecting the reproductive organs, which become doubled or even trebled. In the Hunterian collection there is a proglottid showing twenty-two sexual orifices. Dr Cullingworth, of Manchester, has described a specimen in which the joints are curiously tripartite. As already hinted the true source of this parasite has been proved by experiment ; the first successful worm-feeding having been accomplished by Leuckart. Hosier's, and subsequently my own feeding experiments, immediately followed. Other successful experiments with this species have been conducted by Zurn, Probstmayer, St Cyr, Perroncito, Masse and Pour- quier, and Zenker. As will be again mentioned below Dr Oliver, E.A., whilst stationed at Jullundur, successfully reared the adult tapeworm in a Mohammedan groom and in a Hindoo boy. It will also be seen that Prof. Perroncito reared the worm in a student in fifty-four days. In my own experiments on animals I was assisted by Professor Simonds. The feeding materials were tapeworms expelled from my own patients. We obtained the following interesting results : Exp. 1. A calf. First feeding, Dec. 21st, 1864. Marked symptoms. Slaughtered April 3rd, 1865. Result positive. Exp.2. A calf. First feeding, April 13th, 1865. Second, third, and fourth feedings in May and June. No symptoms. Died on Sept. 3rd, 1865, after thirty-six hours' illness with " cattle OESTODA 59 plague." Result stated to have been negative as far as the muscles were concerned. Viscera not examined. Exp. 3. A Dutch heifer. First feeding, March 3rd, 1865. Three subsequent feedings. Symptoms only slight. Slaugh- tered April 4th, 1866. Result positive. Measles especially numerous in the diaphragm, but all had undergone calcareous degeneration. fl x p. 4. A calf. Fed May 27th, 1872, with ripe proglot- tides. Marked symptoms set in on June 7th, which began to abate on the 12th, and had nearly disappeared by the 20th of the same month. The record of the post-mortem result has been lost ; but the animal was infected. Exp. 5. A calf, which had been made the subject of a " glanders experiment." First fed on Oct. 17th, 1872, and thrice in the following year, Jan. 1st and llth, and March 8th. No symptoms having appeared the animal was kept for six or eight months after the last feeding. Seeming to be free from disease of any kind, it was sold as a sound heifer. Exp. 6. A young heifer calf, of six months. Fed Oct. 18th, 1873, with the mature proglottides of a large beef tapeworm. No symptoms. Slaughtered several months afterwards. Result stated to have been negative. Unfortunately I was not present at the autopsy. Exp. 7. A young heifer. First fed May 19th, 1874, with the joints of a tapeworm, and again on June 12th. No apparent ill effects resulted, but the animal died in October. At the post-mortem examination, made by Prof. Simonds, no parasites were observed. Subsequently I found calcareous specks in the liver which proved to be degenerated measles. Exp. 8. A calf. Fed on or about March 24th, 1875, with sexually mature joints. The calf was put to and remained with a foster mother until it died from disease of the larynx on the 15th of the following July. The animal was ill-treated by its foster parent, and at the post-mortem I observed a larga intercostal cicatrix, evidently the result of injury. In this case I devoted several hours to the exploration of the muscles and viscera. Not a trace of the Gysticercus bovis could be found in the muscles or connective tissues, but the liver contained scores of perfectly developed measles, besides hundreds of others in various stages of calcareous degeneration. On comparing some of the latter with those I had obtained from the preceding experiment the pathological appearances were at once seen to be 60 PARASITES OF MAN identical. It was easy to find and pick out the measles in their cysts from the naturally friable liver. I also detected four Cysticerci in the lungs, two of which had degenerated. Micro- scopic examination confirmed my interpretation of the naked-eye appearances. FIG. 22. Section of the heart of a calf infested by cestode lame. After Mosler. Fragmentary as the above data are, they serve to show that we have hitherto been too hasty in concluding that beef and veal measles reside only in the voluntary and striated muscles of their hosts. The facts here recorded prove that the liver of a calf may be extensively invaded by cysticerci, and yet the animal will exhibit no sign of constitutional disturbance. The cestode tuberculosis may come and go without any diagnostic symptom, whilst a few months suffice for the natural death and decay of the parasite by calcareous degeneration. Thus it becomes extremely probable that many experiments hitherto regarded as negative in their results have really been positive ; the pathological evidences having been either misinterpreted or CESTODA 61 altogether overlooked. Every pathologist is familiar with gritty particles in the various viscera of man and animals, but few are probably aware how constantly these are dead and degenerated Cysticerci. The gritty particle itself may be reduced to the merest point, no larger than the receptaculum capitis of the Cysticercus itself, and in course of time it will disappear entirely. Practically it is satisfactory to have experi- mental evidence of the fact that cattle, as well as other animals, however extensively measled they may have been, can become thoroughly cleansed of the disorder by nature herself. It is only necessary that the diseased animals be separated from infectious influences. Although the beef measle has never yet been found in man, I have for convenience sake introduced the facts of larval parasitism in this place. The sanitary bearings of this subject are far too important to be dismissed in a summary manner. I have shown that the prevalence or rarity of the beef tapeworm in man is strictly dependent upon the habits of the people ; this same cause operating to produce healthy or diseased meat-food, according to the degree of civilisation. In this^onnection the oft-quoted statements of Kaschin respecting the prWalence of tapeworms among the Burates, and the well- known frequency of this entozoon in Abyssinia, need only be alluded to. When discussing the food question in my ' Manual/ I freely availed myself of facts privately communicated by Dr. Joseph Fleming, and I especially referred to the published labours of Lewis, Hewlett, Veale, and other observers stationed in India. Beef measles are extremely common in the cattle of the north- west provinces of India, so much so that severe restrictions have been imposed upon the consumption of ration beef. The presence of a few measles in the flesh of cattle has been deemed a sufficient excuse for condemning and burying entire car- cases. The measle is easily distinguished from that of mutton and pork by the fact that its head is not furnished with hooks, whilst in the place of a rostellum there is a small, centrally placed, retractile disk, which assumes the appearance of a supplementary sucker as in the adult worm. The four true suckers are also comparatively large. The measle usually varies in size from the fourth to the half of an inch in length, but my cabinet contains a specimen nearly an inch long. This was contributed by Dr J. Fleming, who mentions having seen 62 PARASITES OF MAN a measle which, when unrolled, measured nearly an inch and a half in length. Although thousands of these bladder worms must exist in the cattle of England, up to the pre- sent time not a single instance has been recorded of the occurrence of these cystic parasites in the United Kingdom, except in our experimental animals. Notwithstanding my inquiries, I have not yet found a butcher, flesher, meat- inspector, or veterinarian, who has encountered this parasite in any animal slaughtered for the market. Several butchers have denied their occurrence in meat sold by themselves. Even so late as June, 1874, the presence of measles in the flesh of cattle was denied before an assembly of French savans ; yet for many years past I have constantly exhibited measly beef and veal in the lecture room of the Royal Veterinary College. (See the discussion of the Societe de Therapeutique, recorded in the ' Bulletin Gen. de Ther.' for June 30th, 1874, and also the < Jour, de Ther./ No. 14, for July, p. 556, where, however, special remarks on this head have been omitted ; see also the ' Lond. Med. Record ' for July 29th, 1874, p. 472, and the ' Lancet ' for Dec., 1874, p. 794.) Quite in contrast with the statements referred to are those of recent Italian observers. Some few years back Professor G. Pellizzari communicated to the Medico- Physical Academy, at Florence, the results of a series of experiments conducted by himself, with the assistance of Dr Tommasi, in regard to the temperature necessary for the destruction of cysticerci in measled meat. An account of these experiments is published in Tommasi's edition of my ' Manual/ The researches were made in relation to certain sanitary measures effected by the Municipal Commission of Florence, the express object of these measures being to prevent the injurious distribution of measly meat, especially that of swine. Signer Bosi, the superintendent of the public slaughter- houses, granted every facility in his power. In a previously published memoir by Professor E. Perroncito it was statii<', T., 'Lond. Med. Journ./ vol. ii, p. 276, 1829. Alison, S. S., ' Lond .Med. Gaz./ 1844. Barclay, ' Brit. Med. Journ./ Nov., 1868, p. 494. Barker, T. A. 'Lancet/ and ' Path. Soc. Trans.' I8b5. Barlow, 'Lond. Med. Gaz./ 1857,Beith, 'Path. Soc. Trans./ 1852. Bradbury, J. B. (six cases), 'Brit. Med. Journ./ Oct., 1874, pp. 526-558. Idem, 'Brit. Med. Journ./ 1876, vol. ii, p. 646. Brinton, ' Lancet/ 1854. Idem, ' Lancet/ ] 858. Bristowe, T. 8., 'Path. Soc. Trans./ 1851. Idem, 'Path. Soc. Trans./ 1858. Broadbent, W. H., " Hydatids of the Liver ; Paracentesis followed by free Incision ;" ' British CESTODA 143 Med. Journ./ Nov. 30th, 1878. Brodie, B. C. (supposed), 'Lond. Med. Gaz./ 1828. Brook, C., 'Lancet./ Feb., 1868, p. 162. Buchanan, ' Surg. Med. Gaz./ 1861. Budd, W., 'Brit. Med. Journ./ 1859. Chambers, T. K., ' Lond. Med. Gaz./ 1846. Cox, T., ' Lancet/ and < Med-Chir. Trans./ 1838. Crosse, J. G., 'Lancet/ 1837. Curling T. B., ' Med.-Chir. Trans./ 1840. Daly, 0. (supposed), 'Brit. Med. Journ./ 1859. Davies H., ' Path. Soc. Trans./ 1848. Dicken son, 'Lond. Med. Gaz./ 1861; 'Path. Soc. Trans./ 1862. Duncan, A. (near the portal vein), ' Bdin. Med. and Surg. Journ./ 1808. Duncan, P. M. (several cases), ' Prov. Med. and Surg. Journ.,' 1850-52 Elliotson, J., ' Lancet/ 1832. Fearn, 8. W. (immense cyst), ' Brit. Med. Journ./ Nov., 1868, p. 496. Fletcher, T. B. K, ' Prov. Med. and Surg. Journ./ 1846. Freer, W. G., ' Lancet/ and 'Prov. Med. and Surg. Journ./ 18^.Gaitskell, W. (1000 discharged) ' Lond. Med. Repository/ 1815. Gulland, 'Edin. Med. Journ./ I860. Harley, /., ' Lancet/ May, 1866, p. 538, and ' Med. Chir. Trans./ 1866. Idem, in ' St Thomas's Hos- pital Reports/ 1877, p. 291. Eastings, C., 'Brit. Med. Journ./ 1858. Heaton, ' Brit. Med. Journ./ Oct. 31st, 1874, p. 557. Heckford, N., ' Brit. Med. Journ./ Sept., 1868, p. 332. Sillier, ' Lancet/ and ' Path. Soc. Trans./ 1855. Hutchinson, J., 'Lancet/ Oct., 1862,Inglis, A., 'Brit. Med. Journ./ 1859. Leared A. (Hjaltelm's case), 'Path. Soc. Trans./ 1863. Logan (thousands present), 'Path. Soc. Trans./ and ' Med. Times and Gaz./ March, 1865, p. 243. Lyon, E. (several cases), ' Prov. Med. and Surg. Journ.,' 1850. Murchison, C. (rupture through pleura), 'Path. Soc. Trans./ 1861. Idem, 'Lancet/ July, p. 75,1868. Page, 'Brit. Med. Journ./ and 'Lancet/ Nov., 1864. Pavy, F. W. (expectorated), ' Med. Gaz./ 1851. Idem, 'Med.-Chir. Trans./ and ' Lancet/ Sept., 1866, p. 234. Peacock (two cases, expectorated), ' Lond. Med. Gaz.,' and ' Lancet/ 1850. Pemberton, 0. A. (rupturing diaphragm), ' Prov. Med. Journ.,' 1848. Philipson, ' Brit. Med. Journ./ Oct. 31st, 1874, p. 557. Pollock, J. (fatal), ' Path. Soc. Trans./ 1854. Idem (opening into lung), ' Lancet/ Jan., 1865, p. 63. Rees, G. 0., ' Guy's Hosp. Rep./ 1848. Idem (lecture), ' Lond. Med. Gaz./ 1849. Richards, C. C., 'Lancet/ Jan., 1865, p. 261. Roberts, ' Lancet/ 1833. Russell, J., ' Prov. Med. and Surg. Journ./ 1851. Sadler, M. T. (Caesarean section), ' Med. Times and Gaz./ Aug., 1864, p. 141. Salter, H., ' Path. Soc. Trans./ I860. Savory, W. S. (letter), 'Lancet/ May, 1866, 144 PARASITES OF MAN p. 410. Sherwin, E. C. (fatal), ' Edin. Med. and Surg. Journ./ 1823,Sibson, P., 'Lancet/ July, 1868, p. 7G.Sloane, J. (puncture), ' Brit. Med. Journ./ 1858. Thompson H., ' Path. Soc. Trans./ and ' Lancet/ 1858. Trimnell, G. G., ' Lond. Med. Repos./ 1821. Ward, 8. H., ' Lancet/ 1868, vol. ii, pp. 141, 305, and 474. Wearne, V. (perforating diaphragm), 'Brit. Med. Journ./ July, 1864, p. 31. Wilks (escaping by gall-ducts), ' Path. Soc. Trans./ 1860. -- Young, J., ' Edin. Med. and Surg. Journ./ 1829. Hydatids of the liver and other organs together (BIBLIOGRAPHY No. 20 c).Beale, L. (kidney), ' Arch, of Med./ vol. i, p. 31, 1857; see also same case by Bristowe, 'Path. Soc. Trans./ 1853. Billing (lungs), 'Lond. M. and S. Journ./ 1831, p. 58. Griffith, J. W. (abdomen), 'Lond. Med. Gaz./ 1844. Heslop, T. P. (kidney), 'Month. Journ. of Med. Sci./ 1850. Richard- son (kidney, Dr Mackinder's case), ' Lancet/ 1855. Liver cases occurring in America (BIBLIOGRAPHY No. 20 d). Alexander, E. (200 present), ' Boston Med. and Surg. Journ./ 1838. Finnell, 'New York Med. Journ./ 1856, p. 216. Mnu.f, T. (expectorated), Bost. Soc. for Med. Improv., 1859, and ' Brit. Med. and Surg. Journ./ 1860, p. 297. Webber, J. E., 'New York Med. Times/ 1853, and 'Bost. Med. and Surg. Journ./ 1853, p. 126. Hydatids of the lungs and pleura (BIBLIOGRAPHY No. 20 e). Gholmeley, ' Guy's Hosp. Rep./ 1837. Dowling, F., 'Australian Med. Journ./ 1864. Duffin, A. B., ' Beale's Archives/ 1857, vol. i, p. 253. Hare, 'Path. Soc. Trans./ 1857-8. Hill, /., 'Med. and Philos. Comm./ 1784, vol. ii, p. 303. Hutchinson, /., 'Path. Soc. Trans./ 1854. Kirltcs, W. S., ' Med. Times and Gaz./ 1851. Leared, A., 'Path. Soc. Trans./ 1857. Peacock, 'Lancet/ 1850. Ridge, J., 'Guy's Hosp. Rep./ 1836, p. bW.Rigden, G., ' Prov. Med. and Surg. Journ./ 1852. Smith, F. G., 'North Amer. Med.-Chir. Rev./ 1858, p. 333. Todd, R. B., ' Med. Times and Gaz./ 1852. Hydatids of the Kidney (BIBLIOGRAPHY No. 20/.) Adams, A.L.,' Lancet/ 1864, p. 375. Barker, T. H., 'Glasg.Med. Journ./ 1855-6, p. 439. Duncan, 'Liverpool Med. Journ.,' 1834. Dunn, J., 'Lond. Med. Repos./ 1817. Fussell, E. F., ' Lancet/ 1851. Lettsom (two cases), ' Trans. Med. Soc. of Lond./ 1789, p. 33. Ward, W., 'Lancet/ 1846. Wilson, J. (lecture) 'Lond. Med. Repos./ 1822. Hydatids of the spleen, omentum, and abdominal cavity CESTODA 145 (BIBLIOGRAPHY No. 200.). (Anonymous), 'Edin. Med. and Surg. Journ./ 1819, p. 50. Bailey, F., ' Lond. Med. Repos./ 1826. Bright, E. (remarks on cases) 'Guy's Hosp. Rep./ 1838. Bryant, T. (simulating ovarian disease), ( Guy's Hosp. Rep./ 1868, p. 235. Budd, G. (omentum), ' Med. Times/ 1838. Idem (rep. by Parsons), ( Brit. Med. Journ./ 1859. Burman, ' Prov. Med. Journ./ 1847. Crowther, G., ' Edin. Med. and Surg. Journ./ 1826, p. 4Q.Greenhow, E. H., ' Lancet/ 1862. Little, W. I. (simulating ovarian disease)/ Brit. Med. Journ./ 1857. Macleay, K., 'Edin. Med. and Surg. Journ./ 1806. M or ley, J. (partly pelvic), ( Lancet/ 1845. Newman, W. (simulating ovarian disease), ' Obstetr. Soc. Trans./ vol. iv, 1862. Obre (peri- toneal), ' Path. Soc. Trans./ 1854. Ogle, J. (omentum), < Path. Soc. Trans./ I860. Simpson, A. E. (peritoneal), ' Edin. Med. Journ./ 1861-62. Simpson, /. Y., ' Assoc. Med. Journ./ 1854, p. 137. Thompson, T., ' Lancet, 1843. Thompson, A. T. (simulating ovarian disease), ( Lancet/ 1833. Hydatids within the pelvic cavity (BIBLIOGRAPHY No. 20 h). Birkett, /.(voided), < Guy's Hosp. Rep./ 1851, p. WO. Bryant, T., ' Lancet/ 1865, pp. 566 and 589. Corrigan (ovarian), ' Dub. Quart. Journ./ vol. i, 1846. Crampton (ovarian), f Dub. Quart. Journ./ vol. ii, 1846. Curling, T. B. (bladder), 'Med. Times and Gaz./ 1863. Farre, A., t Lancet/ 1862. Habershon, ' Path. Soc. Trans./ I860. Hughes, ' Lond. Med. Gaz./ 1861. Hunter, T., ' Trans, of Soc. for Improv. of Med. and Chir. Knowledge/ 1793, p. 34. Jennings (simulating pregnancy), 'Dublin Quart. Journ./ 18b5.Lowdell, 'Lancet/ 1846. Maunder, 'Lancet/ Sept., 1864, p. 351. Sadler, M. T. (voided), ' Med. Times and Gaz.' 1865. Simon, J. (voided), ' Lancet/ 1853. WaMey, 'Lancet/ 1863. White, 'Med. Gaz./ 1842. Hydatids of the heart and blood-vessels (BIBLLIOGRAPHY No. 20 i). Bigger, 'Dub. Path. Soc.' Rep. in ' Lancet/ 1830. Budd, G., ' Path. Soc. Trans./ 1839. Coote, H., ' Lond. Med. Gaz./ 1854. Goodhart, ' Brit. Med. Journ., Nov. 27, 1875. Price, D., 'Lond. Med. Repos./ 1822. Smith, E., 'Lancet/ 1838. Trotter, ' Chem. and Med. Essays/ 1736. Wilks (Hen- derson's case), ' Path. Soc. Trans./ 1860. Hydatids of the brain and cranial cavity (BIBLIOGRAPHY, No. 20 /). (Anonymous) 'Lancet/ April, 1864, p. 444. Bailey, F., 'Lancet/ 1825; 'Lond. Med. Repos./ 1826. Barker, T. A., 'Path. Soc. Trans./ 1858. Bennett, J. E., 'Med. Times and Gaz./ Jan.,1862. Berncastle, /., ' Lancet/ 1846. Bree, C. E., ' Lan- 10 146 PARASITES OF MAN cet/1837. Brittan,F., ' Brit. Med Journ./ 1859. Burton, 'Med. Times and Gaz./ 1862. Dagleish, G., ' Lancet/ 1832. Fletcher, T. B. #., 'Assoc. Med. Journ./ vol. iii, p. 161, 1855. Heading- ton, ( Edin. Med. and Surg. Journ.,' vol. xv, 1819, p. 504. Helsham, 'Med. Comment./ vol. xiii, 1788, p. 289. Macnamara, W. H., f Brit. Med. Journ./ vol. ii, p. 616, 1876. Rigden, G., ' Prov. Med. and Surg. Journ./ 1852. Stewart, J. 3 ' Lancet/ 1848. Sturton, < Lancet/ 1840. Wilson, E., ' Lancet/ 1848. Hydatids of the bones (BIBLIOGRAPHY No. 20 I). Cobbold, T. S., " Notice of Specimens of Tibial Hydatids in Nottingham," ' Brit. Med. Journ./ 1865, and in the ' Veterinarian/ Feb., 1866. Idem, "Notice of Specimens from the Tibia in the Mid. Hosp. Museum," ibid. Cooper, A., " Foster and Lucas's case affecting the Tibia," ' Surg. Essays/ Lond., 1818. Coulson, W. (tibia), 'Med.-Chir. Trans./ 1858; see also Daubeny, H., 'Path. Soc. Trans./ 1858. Erichsen, J. E., in his 'Surgery/ 4th edit., pp. 728, 823, and 948, Lond., 1864. Hunter, W. (tibial, Mus. Spec, at Glasgow), quoted in ' L'Experience/ 1838, p. 531. Keate, R. (os frontis), ' Med.-Chir. Trans./ 1819. Lambert, J. (tibia), f Lancet/ 1826. Thompson, E. (Hearne's tibial case), ' Path. Soc. Trans./ 1859. Webster, F. W. (tibia), 'New Eng. Med. Journ. of Med. and Surg./ 1819. Wickham, W. J. (tibia), 'Lond. Med. and Phys. Journ./ 1827. Hydatids of the breast, muscles, and soft parts (BIBLIOGRAPHY No. 20 m). Adams, J. (abdominal parietes), 'Lancet/ 1851. (Anonymous), " Hyd. in the Eye of a Girl," ' Boston Med. and Surg. Journ./ 1849, p. 28. Baird, J. (muscles), ' Edin. Med. and Surg. Journ.,' 1821. Birkett, J. (mammary), 'Lancet,' March, 1867, p. 263. Brodie, B. G. (near scapula), 'Lancet/ 1818. Bryant, T. (thigh), ' Path. Soc. Trans./ 1859. Idem (thigh), 'Lancet/ 1862. Idem (breast), 'Path. Soc. Trans./ and 'Lancet/ Nov., 1865, p. 565. Cholmeley (from right side), ' Lancet/ 1826. Cooper, B. B. (neck and breast, two cases), 'Guy's Hosp. Rep.' 1851. Idem, in Birkett's work on the 'Breast/ p. 183; the 'Institute/ vol. i. p. 119, 1850. Dixon, J. (neck), 'Lancet/ 1851. Henry, M. (breast), 'Lancet/ Nov., 1861, p. 497. Hewndon, A. (neck), by Tyson, in ' Phil. Trans./ 1706-7, vol. xxv, p. 2344. Jones, 8. (subperitoneal), 'Path. Soc. Trans./ 1854. Rankine, J., " Supposed Hyd. in Synovia! Sheaths," 'Edin. M. and S. Journ./ 1830. Sands (neck), 'Amer. Med. Times/ 1861, vol. ii, p. 376. White (breast and arm), 'Lancet/ 1839. CESTODA 147 Hydatids of uncertain seat, or miscellaneous cases and obser- vations (BIBLIOGRAPHY No. 20 n). Barrett, ' Lond. Med. Gaz./ 1838. Durrani, G. M. (Ipswich Hosp.), ' Prov. Med. and Surg. Journ./ 1851. Fagge, H., ' Lancet/ July, 1868, p. 76. Greenhow, J. M. (intestinal), ' Lancet/ 1823. Howship, J. (case, with speculative remarks), ' Bdin. M. and S. Journ.,'' l835.MacGillivray, P. H. (orbit, &c.), 'Austral. Med. Journ./ Aug., 1865. Idem, ibid., March, 1867. Idem (3rd series of cases), ibid., July, 1872. Idem (treatment with kamala), ibid., July, 1872. Markham, W. 0., " On the ' son hydatique/ " ' Assoc. Med. Journ./ 1856, p. 1072. Musgrave (letter to Sir H. Sloane), ' Phil. Trans./ vol. xxiv, 1704-5. Phillips, ' Lancet/ July, 1868, p. 77. Russell, J J., ' Dub. Journ./ 1838. Salter, H., 'Path. Soc. Trans./ 1854. Ward, T. 0. 3 'Lond. Med. Gaz./ 1837. Hydatids of animals (acephalocysts) (BIBLIOGRAPHY No. 20 o). Bollinger (see Bibl. No. 4>9).Oobbold, ' Manual/ 1. c. (Bibl. No. 2), 1874. Crisp, E. (in a turkey and in hogs), 'Path. Soc. Trans./ 1863. East, J. (see Steel). Findeisen, "Echin. in der Lunge," ' Eepertorium fiir Thierheilkund./ 1875, s. 48. Gross, 8. D. (in swine), 'Elements of Path. Anat./ 1845, p. 118. Hunter, J., "A Cyst (hydatid) which was filled with water, formed in and filling up the Bone (humerus) of an Ox (from Hunterian MS.)," more fully described in the ' Catalogue of the Mus. Lond. Coll. Surg./ " Path.," vol. ii, prep. No. 864, p. 201, 1847. Idem, "On Hydatids in Sheep" (supp. to Trans, of a Soc., 1. c., supra), 1793. Hutchinson, J., " Hydatid in the Eye of a Horse," ' Path. Soc. Trans./ and 'Lancet/ 1857. Huxley, T. H., " On the Anatomy and Deve- lopment of jEchinoc. veterinorum (from a Zebra), " ' Proc. Zool. Soc./ 1852. KirJcman, J., " Chronic Disease of the Bones of the Cranium of a Horse, associated with the existence of Hyda- tids within a Cyst at the inferior part of the Orbit," the ' Vete- rinarian/ vol. xxxvi, p. 77, 1863. Lepper, " Hydatids in the Kidney of a Lamb," the 'Veterinarian/ 1863, p. 524. Martin, J. (in the liver of a sow), ' Yet. Assoc. Trans./ 1842-3, pp. 330 and 364. Moorcroft, W. (in the brain of a cow), ' Med. Facts and Observ./ vol. iii, 1792. Morgan, A. (in the brain of a mare), the ' Veterinarian/ 1855, p. 396. Peech, S. (in the muscles of a horse), the 'Veterinarian/ 1854, pp. 80 and 209. Siedamagrotzky (see Bibliog. No. 49). Simonds, J. B., " Re- marks on Mr. Scruby's case of Hydatids in the Liver of a 148 PARASITES OF MAN Sheep/' ' Trans, of Vet. Assoc./ 1842-3, p. 331. Steel, J. H. (in liver of a cow; Mr East's case), the 'Veterinarian, 1878, p. 441. Stoddart (in liver of a cow), the 'Veterinarian/ 1838, p. 637. Thudichum, J. L. W. (in sheep), ' Assoc. Med. Journ./ 1856, p. 195. Vincent, J. P. (in horse, causing lameness), the 'Veterinarian/ 1848, p. 674. Walker, A. (in the liver of a sow), 'Vet. Record/ 1846, p. 185. Woodger (in the brain of a horse), the ' Veterinarian/ 1863, p. 75. Foreign Literature. Human Hydatids (BIBLIOGRAPHY No. 20 p). Backer, 'Zur statistik der Echinoc./ Berlin, 1868. Davairie, C., ' Traite ' (1. c., Bibl. No. 1), p. 350, 1860 ; 2nd edit. p. 369, 1877. Idem, " Recherches sur les hydatides, les echinoc., &c.," ' Gaz. Med. de Paris/ 1855. Idem, " Recherch. sur le fremisse- ment hydatique/' 'Gaz. Med./ 1862. Eschricht, ' Danske vi- denskab. selsk. forhandl./ 1853. Finsen, ' Ugeskriftfor Lager/ Bd. iii, 1867; see also 'Brit, and For. Med.-Chir. Rev./ 1868, p. 324; also ' Schmidt's Jahrb. fiir Med./ 1867, s. 181. 6?ue- rault, " Sur lamaladie hydatique, &c.," ' Gaz. des H6p./ 1857. Hearn, A. W., 'Kystes hydatiques du poumon et de la plevre/ Paris, 1875. Heller, A., " Die Schmarotzer der Leber," von ' Ziemssen's ' Handbuch d. Spec. Pathol. und Therapie/ Bd. viii, s. 559. Krabbe, H., " Maladie causee en Island par les Echino- coques," in his 'Recherches Helminthologiques/ p. 41, Paris, 1866; ' Helm. Unders^gelser/ Copenhagen, 1865, p. 40. Idem, 'Die echinoc. der Islander/' ' Archiv fiir Naturg./ 1865, and in 'Denmed. Skole i Reykjavik/- 1868. Idem (see T. R. Jones, Bibl. No. 2). Leuckart, R. (1. c., Bibl. No. 1), Bd. i, s. 335, 1863; Bd. ii, s. 859, 1876.- Linder, ' Echinococcen der Leber/ Leipsic, 1869. Naunyn, ' Archiv fiir Anat., Physiol./ &c., 1862-3. Neisser, A., 'Die echinococcen Krankheit./ Berlin, 1877. Rassmussen, 'Bidrag til Kundskab om Echinoc.,' &c., 1865; see also 'Brit, and For. Med.-Chir. Rev./ 1866, p. 285, and 1867, p. 424. Schmalfuss, ' Ueber Leberechinococcus/ Breslau, 1868. Tommasi, T., f Storia di un caso di Echinoc.,' &c., in an appendix (Nota) to his edition of my 'Lectures' (Vermi, &c.), Milan, 1873, p. 153. NOTE. As Leuckart, Davaine, and especially Neisser offer exhaustive analyses of the French and German literature of human hydatids, I will only give the authors' names attached to such additional foreign memoirs and cases as have been published in England. These are quoted in my ' Introductory Treatise on the Entozoa.' Full references will be found in the NEMATODA 149 "Bibliography" of that work under the following heads: Andral (pulmonary veins), Angeli, Auglagnier (bladder), Baillarger (brain), Boinet (liver), Chaubasse (abdominal), Gruveilhier (liver and spleen), Dupuy (hydatids in animals), Demarquay (liver), Dupuytren (muscles and viscera, &c.), Fouquier (lungs), Gayet (liver), Goyrand (liver), Guerard, Guillot, Hedinger (brain), Heintz (liver), Held (thigh), Heller (lip), Klencke (blood, &c.), KuTin > Lafforgue (liver), Legroux, Livois, LuschJca (liver), Martinet (brain, liver), Maug (hand), Meissner, Miched (brain), Moissenet (liver), Montault (brain), Morrisseau, Nicolai (liver), Oerstelen (kidney), Pohl (abdominal), Quinquirez (bladder), Recamier (abdominal), Richard (liver), Roget (lungs), Roux (pelvic), Riittel (brain), Schleissner, Sichel, Sommering (eye), Skoda, Tomowitz (bladder), Zeder (brain). Additional references to the echinococcus disease as it occurs in animals will be found at the close of the section devoted to the parasites of Ruminants (Bibliography No. 49), and I shall recur to the subject of mortality from " worms " further on. SECTION III. NEMATODA (Round Worms). Trichina spiralis, Owen. The progressive triumphs of biological science are well epitomised in the history of the discovery, and in the record of the gradual manner in which we have obtained our present complete knowledge of the structure and development of this small entozoon. Although the facts connected with the original discovery are clear and indisputable, much error still pervades foreign litera- ture on this head. Without a doubt Mr Hilton was the first to suggest the parasitic nature of the capsules first spoken of as " gritty particles." With Sir James Paget, however, rests the true discovery and determination of the nematoid character of the worm itself. With Professor Owen remains the honor of having first scientifically verified, described, and named the entozoon. Some have sought, without good reason, to alter Owen's nomenclature ; yet not only the generic title, but nearly all else that he wrote concerning the parasite, must be allowed to stand. In relation to the capsules, it is true that prior claims of discovery have been put forward ; but whilst Peacock's prepara- tion of the " little bodies " testifies to the fact of his having 150 PARASITES OF MAN seen the capsules before other English observers, including Wormald, it was Hilton who first surmised their parasitic character. As for the claims of Klencke and Tiedemann, they are practically of no value, even if it be admitted that the former may have at an early period seen something resembling this nematode, and that the " stony concretions " encountered by the latter were degenerated capsules. On no subject have I desired to write with more accuracy and precision than on this, and lest the above remarks should appear to be somewhat partial, I now purposely re-state the facts as they have presented themselves to me during a full and prolonged study of the entire literature of the subject. If it be asked with whom rests the discovery of Trichina, the reply must be framed with a due regard to precise issue at stake. The first recognition of the capsules as parasitic products is fairly claimed by Hilton ; the worm by Paget ; the zoological allocation and nomenclature by Owen ; the udult worm by Virchow ; the developmental phenomena by Leuckart ; the rearing of the larvae by Herbst ; and to crown all, the clinical importance of the parasite by Zenker. Due regard being had to these relative claims, I think the following more extended statement will be found to be true and just in all its bearings. In the year 1834 Sir James Paget, then a student, first actually determined the existence of the nematode entozoon, which was subsequently more completely described by Professor Owen. The discoverer was assisted by the celebrated botanist, Kobert Brown, who lent his microscope for the purposes of examination. In the following year Professor Owen first scientifically described and named the flesh-worm (Trichina spiralis) in the published transactions of a learned society. He first fully interpreted the true zoological position of the parasite. Sir J. Paget' s colleague, Mr. Wormald, had " more than once " previously noticed the characteristic specks " in subjects dissected at St Bartholomew's Hospital." He transmitted the individual specimens which enabled Owen to draw up his valuable paper. It is clear, however, that Mr Hilton was the first to suggest the parasitic and animal nature of the specks observed in human muscle. As the " find " was made in 1832, he anticipated Wormald in his observation of the " gritty " particles in dissecting-room subjects, describing the bodies as " probably depending upon the formation of very small Cysticerci." Nevertheless, according to Dr Hodgkin, NEMATODA 151 " the first observation of these little bodies was made in 1828 " by Mr H. Peacock. The latter made a dry preparation of the sterno-hyoideus muscle to display the specks. That preparation is the oldest in existence, and may be seen in Guy's Museum. It may further be remarked that Henle, Kiichenmeister, Davaine, myself, and others, have pointed to a notice by Tiedemann as probably, or possibly, indicating a prior observa- tion of the specks. Leuckart rejects the evidence. Dr Pagen- stecher appears to be in doubt as to the nature of the bodies in question. As the passage in question possibly gave a rough and imperfect description of the now familiarly known calcified Trichina capsules, I give a translation of it (Froriep's ' Notizen/ 1822, Bd. i, s. 64) : " At a post-mortem examination of a man who had been a great brandy- drinker, and who died from thoracic dropsy after several severe attacks of gout, Tiede- mann found white stony concretions in most of the muscles, especially at the extremities. They lay in the cellular tissue between the fibre-bundles, frequently also attached to (or near) the walls of the arteries, being from two to four lines long, and roundish. The chemical examination conducted by Gmelin yielded seventy-three parts phosphate of lime, seven parts car- bonate of lime and twenty parts animal matter, resembling albu- men or fibrin." In regard to this notice Dr Pagenstecher (' Die Trichinen/ s. 4) has remarked that Tiedemann' s ff communica- tion was also referred by Henle to such a parasitic development when he subsequently found Trichina ; and in this sense it was afterwards received by Diesing, Kiichenmeister, and Davaine. But it has been rejected by Leuckart on account of the size (from two to four lines) and seat of the concretions. True, it has never yet been observed that the capsuled Trichina (not measur- ing a tenth part of that diameter) subsequently constituted centres of gouty deposit exceeding their own bulk, nor is it likely that they should. Seeing, however, as we often do, that errors respecting size have crept into works on Trichina, we shall not need to lay much stress upon these statements ; still less so since the notice is very superficial, and its character is essen- tially of a physiologico-chemical nature. But this, at least, seems to us decisive, that when BischofF, at Heidelberg, wrote on a case which occurred in Heidelberg, not one single word was mentioned respecting a former case, if such should have happened, although Tiedemann and himself were on terms of close intimacy." So much for Tiedemann. In regard to 152 PARASITES OF MAN Klencke' s claims, the same observer writes : " Klencke has asserted that he had already drawn Trichinae in the year 1829, and that he had seen them again in 1831. This subsequent statement has no kind of confirmation. The unreliableness, mistakes, and self-deceptions in the helminthological writings of Klencke have been repeatedly exposed some twenty years ago." Prior to this criticism by Pagenstecher, Professor von Siebold and several other well-known helminthologists had already com- mented on Klencke' s assertions in the same destructive manner. In regard to the experimentation and the valuable instruction thus acquired, it appears tfaaJLHerbst was the first to rear muscle-flesh-worms, or encapsuled Trichinae, in animals (1850) ; whilst Virchow was probably the first to rear and recognise sexually-mature intestinal Trichinae in a dog ('Deutsche Klinik/ 1859, s. 430) ; yet, without doing injustice to others, it must be added that it remained for Prof. Leuckart to offer a full, complete, and correct solution of the principal questions relating to the source and mode of genesis of the flesh-worm (1860). Leuckart likewise did good service by disproving the erroneous views that had been put forth by Kuchenmeister. Lastly, all these brilliant results culminated in the clinical observations of Zenker, who opened out a new epoch in the history of trichinal discovery. Pro- fessor Zenker was the first to detect the young in the act of migration, and he likewise primarily demonstrated the fact that the larval parasites were capable of producing a violent disease in the human body. x-**"~"Never in the history of biological science have more valuable issues followed the method of expe- riment upon animals. Not only has human life been thus saved, but animal life also. State- medicine and sanitation have received an immense impulse. The good that has already resulted is simply incalculable ; nevertheless, in the eyes of a set of ignorant fanatics who infest this country, all experiments " involving cruelty to animals " 35 sexually ou g^ * be prevented at any cost. The further ^'nS? P r g ress f biological science in England has After Leuckart. hereby sustained a severe check. NEMATODA 153 The Trichina spiralis in its sexually-mature state is an ex- tremely minute nematode helminth, the adult male measuring only the T '^th of an inch, whilst the perfectly developed female reaches a length of about i". The body is rounded and filiform, usually slightly bent upon it- self, and rather thicker behind than in front, especially in the males. The head is narrow, finely pointed, unarmed, with a simple, central, minute oral aper- ture. The posterior extremity of the male is furnished with a bilobed caudal appendage, its cloacal or anal aperture being situated between these divergent appendages. The penis consists of a single spicule, cleft above, so as to assume a V-shaped outline. The female is stouter than the male, bluntly rounded posteriorly, having the genital outlet placed far forward, at about the end of the first fifth of the long diameter of the body. The eggs measure T ~" from pole to pole. The mode of reproduction is viviparous. As commonly observed in the human body our young Trichinae appear as spirally- coiLed worms in the interior of small, globular, oval, or lemon- shaped cysts, which latter appear as minute specks scarcely visible to the naked eye. These specks resem- ble little particles of lime, being more or less calcareous accord- ing to the degree of degenera- tion which their walls have undergone. In shape and general aspect they are not altogether unlike the eggs of certain nema- toid worms, but their size alone sufficiently distinguishes them. They measure on an average ^" in length by yjg" in breadth. FIG. 36. Larval Trichina coiled within its capsule. After Bristowe and Rainey. 154 PARASITES OF MAX The organised capsules are not essential to the further develop- ment of the parasite, and are rather to be regarded as abnormal formations, or rather, perhaps, as products resulting from an effort of nature to protect and thus prolong the life of the occupant. They are frequently altogether wanting. The cap- suled Trichinae measure ^" in length by about ^" in breadth. When fully formed they not only exhibit a well-marked digestive apparatus, but also reproductive organs, which are often, indeed, sufficiently developed to determine the sex. Notwithstanding the large number of experiments that have been more or less recently made by investigators, little or nothing has been discovered calculated to disturb the conclu- sions set forth by Leuckart, who writes as follows : " (1) Tri- china spiralis is the juvenile state of a little round worm, pre- viously unknown, to which the generic title of Trichina must remain attached. (2) The sexually mature Trichina inhabits the intestinal canal of numerous warm-blooded animals, espe- cially mammalia (also of man), and constantly in great num- bers. The duration of its life extends from four to five weeks. (3) At the second day after their introduction the intestinal Trichinae attain their full sexual maturity. (4) The eggs of the female Trichinae are developed within the uterus of the mother, into minute filaria-like embryos, which, from the sixth day, are born without their egg-shells. The number of young in each mother-worm is at least from ten to fifteen thousand. (5) The new-born young soon after commence their wandering. They penetrate the walls of the intestine and pass directly through the abdominal cavity into the muscles of their bearers, where, if the conditions are otherwise favorable, they are developed into the form hitherto known. (6) The directions in which they proceed are in the course of the inter- muscular connective tissues. (7) Only the striped muscle (that of the heart excepted) contains Trichinae. The majority of the wandering embryos remain in those sheathed muscular groups which are nearest to the cavity of the body, especially in those which are smaller and most supplied with connective tissue. Speaking generally, their number decreases with the distance from the abdomen, being, however, more numerous in the anterior half of the body. (8) The embryos penetrate into the interior of the separate muscular bundles, and here already, after fourteen days, acquire the size and organisation of the well-known Trichina spiralis. (9) Soon after the in- NEMATODA 155 trusion of the parasite the infested muscular fibre loses its original structure, the fibrillae collapse into a finely granular substance, whilst the muscular corpuscles change into oval nucleated cells. (10) The infected muscular bundle retains its original sheathing up to the time of the complete develop- meut of the young Trichinae, but afterwards its sarcolemma thickens, and begins to shrivel at the extremities. 11. The spot inhabited by the rolled-up parasites is converted into a spindle-shaped widening, and within this space, under the thickened sarcolemma, the formation of the well-known lemon- shaped or globular cysts commences by a peripheric hardening and calcification. This degeneration commences several months after the wandering. Immature muscle - Trichinae are not capable of producing infection. (12) The migration and deve- lopment of the em- bryos also take place after the transporta- tion of impregnated Trichinae into the in- testines of a new host. (13) The fur- ther development of the muscle-Trichinae into adult animals is altogether indepen- dent of the forma- tion of the calcareous shell, and occurs as soon as the former have reached their completion. (14) Males and females are already recog- nisable in their larval state. (15) The immigration of the Trichina-brood in masses produces very grave or even fatal consequences, such as peritonitis (from the embryos perforat- ing the intestinal walls), pain, and paralysis (resulting from the destructionof the infected muscular fibres). (16) The infection of man occurs especially through swine. (17) The^ muscle -Tri- chinae are so capable of resistance that they are by no means in all cases destroyed by the ordinary methods of roasting, cooking, pickling and smoking. (18) As a rule, swine obtain Trichinae from rats, to which latter we also as the natural bearers have to convey them. Microscopic examination of FIG. 37. Immature female Trichina from muscle. After Leuckart. 156 PARASITES OF MAN flesh is, therefore, urgently recommended as a public preventive against all danger from Trichinae." As a summary the above conclusions are well nigh exhaustive; but whilst I purposely avoid entering into mere clinical details, there are points of hygienic interest to which I must allude. Thus, as regards the number of larval Trichinae in any one " bearer " at a time, this, of course, must be extremely variable, but it may amount to many millions. In one of the cats on which Leuckart experimented, he estimated a single ounce of its muscle-flesh to harbour no less than 325,000 Trichinae. I find that a relatively similar degree of infection in an ordinary human " bearer" would yield thirty millions. In the case of one of my own experimental animals, a pig, I reckoned that there were at least sixteen millions of Trichinae. The larvae were about ten months old and enclosed within perfectly formed capsules ; nevertheless, the animal had never displayed any symptom of irritation. In a trichinised human subject, examined by Dr Thudichum, it was estimated that 40,000,000 parasites were present. My own estimate, calculated from specimens of muscle obtained from the same case, gave 100,000,000 as the approximate number of worms present. In the only outbreak of Trichinosis occurring in England, details of which will be given further on, I found that the flesh of the hog that had caused the local endemic contained upwards of 80,000 Trichinae to the ounce. The consumption of a pound of such flesh would be capable of producing a collective progeny of some- thing like 400,000,000 within the human " bearer." In the year 1865 I conducted a series of experiments upon upwards of a score of animals, including seven birds, the latter all yielding only negative results. So far as muscle-Trichinae were concerned my experiences accorded with those of Professors H. A. Pagenstecher and C. J. Fuchs, at the Zoological Institute in Heidelberg. These experimenters found that the ingested muscle- Trichinae acquired sexual maturity within the intestinal canal of their avian "hosts;" but they never found young Trichinae in the muscles of the birds, nor did they perceive any evidences of an attempt on the part of the escaped embryos to effect a wandering or active migration on their own account. Clearly, if the bird's intestinal canal were a proper territory for the residence of sexually mature Trichinae, we should have found abundance of wandering non-encapsuled flesh-worms and also sexually-immature muscle-Trichinae enclosed in well-formed NEMATODA 157 capsules. Not a few persons still entertain the notion that Trichinae are liable to infest all kinds of warm-blooded, and even also many kinds of cold-blooded animals, such as reptiles and fishes. Certain nematodes found in earth-worms have been described as TrichinaB ; and consquently, pigs and hedgehogs were said to become trichinous through eating these annelids. The minute flesh-worms described by Bowman from the muscle of the eel are not true TrichinaB, any more than the somewhat similar parasites which Eberth found to infest the muscles of the frog. The same may also be said of Dr Salisbury's urinary Trichinae, which are the larvae of Filaria Bancrofti. Deducting the seven birds, and also six other animals where no examination after death was possible, I ascertained the result of my worm-feedings in sixteen instances. Nine of the experiments were entirely successful, the infected animals comprising four dogs, two cats, one pig, one guinea-pig, and a hedgehog. Carnivorous mammals, especially those subsisting on a mixed diet, are the most liable to entertain Trichinae, but it is quite possible to rear them in herbivora. Thus, Pagenstecher and Fuchs succeeded in rearing muscle-Trichinae in a calf, and they found three female intestinal Trichinae in a goat, but apparently no muscle-flesh-worms, althougth twenty-seven days had elapsed since the first feeding with trichinised rabbit's flesh. In three sheep on which I experimented no trace of Trichinae could be found. There is no practical need for any further experi- ments on herbivora, for it is quite clear that, in their natural state, herbivorous mammals can seldom have an opportunity of infesting themselves, whilst the reverse is the case with swine, carnivorous mammals, and ourselves. Because many quadrupeds become trichinous, it does not follow that all mammals are liable to be infested. In the case of most parasites we find the species limited to a larger or smaller number of hosts. On the other hand, in not a few cases, the range of the entozoon is limited to a single territory or host. In conducting the experiments above mentioned I was assisted by Professors Simonds and Pritchard, of the Royal Veterinary College. As they were the only researches con- ducted on any considerable scale in England, I subjoin a few details of them. Dr Thudichum's experiments were, I believe, confined to rabbits. Exps. 1 and 2. On the 15th of March, 1865, an ounce of 158 PARASITES OF MAN flesh containing Trichinae was administered by myself to a black bitch. The dog being destroyed five days subsequently, neither intestinal nor muscle-Trichinae were discovered. It was thought that the dog had thrown up the bolus, which was strongly saturated with chloride-of-zinc solution. The bolus consisted of a portion of the pectoralis major of a subject brought to the dissecting-room at the Middlesex Hospital. The cysts were highly calcified, but the majority contained living embryos, which were quite unaffected by the zinc solution injected into the body to prevent decomposition. At the same date a small white puppy was experimented on and examined with precisely the same results. In either case it was too early to expect muscle-flesh-worms to have become developed. Exp. 3. Half an ounce of the same trichinous human flesh was given (at the same date) to a black-and-tan puppy reared at the Royal Veterinary College, a second " feeding" being administered on the 21st of March, or six days after the first. In this case Mr Pritchard, who fed the animal, took the pre- caution to chop the muscle into small pieces, and to mix it with other food, in order that the flesh might be the more readily retained in the stomach. The puppy was not destroyed until the 15th of the following June, when, on examination, numerous encysted but non-calcified muscle-Trichinae were found in all the voluntary muscles subjected to microscopic scrutiny. Exp. 4. An ounce of the same flesh was given to a dark- colored pig on the 15th of March, and again on the 20th, several other " feedings" being also administered during the month of April, 1865. It was destroyed on the 16th of May, but no Trichinae were detected. Exp. 5. An ounce of the same human muscle-flesh admi- nistered to a small sheep (which was subsequently killed on the 29th of June) also produced negative results. Exps. 6 and 7. " Feedings" were at the same time adminis- tered to a rat and mouse. The mouse died on the 2nd April, when I examined its muscles without success. On the follow- ing day the rat unfortunately made its escape, but whether trichinised or not cannot be said. Exp. 8. An ounce of trichinous human flesh was given to a donkey, in the form of " balls," on the 20th of March ; and during the month of June four other separate " feedings" with trichinous dog's flesh were also administered. The animal was removed from the College without the result being ascertained. NEMATODA 159 Exp. 9. From the 15th to the 20th March, 1865, inclusive, three small Trichina " feedings" were likewise administered to a guinea-pig. This little animal was not destroyed until the 15th of the following June, when a positive result was obtained. The pectoralis transversus and other muscles were found to harbour a considerable number of encysted Trichinae. Exp. 10. On the 20th March, and again on the 21st (1865), " feedings" from the same human subject were administered to a hedgehog. On the 26th of April the animal seemed to be attacked with symptoms of Trichinosis. It refused food, kept its head extended, and the eyelids closed. On the 27th it appeared much worse, and on the morning of the 28th it was found dead. On the 29th I examined the flesh, and found abun- dance of living Trichinae in the muscles. The capsules were very thin and transparent. A few days later Mr Simonds also examined the flesh, and confirmed this result. Exps. 11 and 12. Two chickens were fed, on the 21st of March, with the same material. One of the birds died on the 24th, when I examined the intestines and detected one or two very minute nematodes, which, at the time, I believed to be imperfectly developed Trichinae, but subsequently saw reason to alter my opinion. The other bird died on the 3rd of April, and certainly contained no muscle-Trichinae. Exp. 13. On the 22nd and 23rd of March "feedings," amounting to an ounce of flesh in all, were given to a mole. This animal was returned to the care of Mr Charles Land, who had previously sent it to the Veterinary College. He subse- quently reported that, after observing the mole to be "working" for two or three days, he lost all trace of it, and concluded that it had either escaped or was dead. Exp. 14. On the 1st and 2nd of May portions of the left fore extremity of the hedgehog (in which we had successfully reared Trichina from the Middlesex-Hospital subject) were offered by Mr Simonds to a cat. It ate the flesh very readily, consuming the entire limb. On the 15th of the following June the cat was killed, when living Trichinae were found within all the muscles which we examined. Exp. 15. At the same dates a young terrier dog was simi- larly treated, but did not take the " feeding" so readily. In this case the left hind extremity of the hedgehog was employed, and what was not eaten voluntarily was forcibly introduced. On the 1st of June the dog was attacked with " distemper," and 160 PARASITES OF MAN died on the 8th of the same month. On examination we found several living Trichinae in the sterno-maxillaris and other muscles. Some of the parasites were encysted. Exp. 16. From the 9th to the 12th of June inclusive four separate worm-feedings with the flesh of the trichinised terrier-dog were administered to a crow. The bird was killed some months afterwards and sent to me for examination. Its muscles were entirely free from Trichinae. Exp. 17. From the 9th to the 17th of June inclusive seven separate worm- feedings were administered to a pig. One of the " feedings " was with the trichinised guinea-pig's flesh, the others from the dog. This animal was not destroyed until the 4th of April, 1866, when all the muscles which I examined were found extensively infested with Trichinae. There were probably not less than 16,000,000 present, all being alive and enclosed within perfectly-formed capsules, none of which latter exhibited any traces of calcareous deposition. Exp. 18. Four separate feedings with trichinous dog's flesh were likewise, at the same dates as the foregoing, administered to a rat. This experimental animal, however, like the one previously mentioned, contrived to make its escape. I fear it was well trichinised. Exp. 19. About the same date trichinous "feedings " were given to a black puppy (bred at the Veterinary College). The dog was killed on the 18th of August, 1866, having also been made the subject of an echinococcus-f ceding, when I found abundance of encysted Trichinae within the voluntary muscles. Exp. 20. Four separate worm-feedings with the flesh of the trichinised guinea-pig were given to a sheep on the 15th, 16th, 17th, and 19th days of June, 1865. The experimental animal was destroyed on the 29th of the same month, but the result was negative. Exps. 21 and 22. " Feedings " with the guinea-pig's flesh four in the one case and three in the other were also ad- ministered by Mr Simonds (from the 15th to the 19th of June, inclusive) to a chicken and goose respectively. These birds were destroyed some months afterwards and sent to me for examina- tion, but the most careful scrutiny failed to detect any Trichinae within their muscles. The goose was cooked and eaten without the slightest hesitation. The chicken I found too tough for consumption. Exp. 23. On the 28th of March, 1866, I obtained a small NEMATODA 161 quantity of muscle from a highly trichinised German subject, who died from the effects of an accident at the London Hospital the day previous. The case was fully reported by Dr Thudichum in a new journal, called ' Scientific Opinion ' (No. 4, April 25th 1866, p. 55). During the same day (at 2.30 p.m.) I fed a dog with part of this human flesh. On the morning of the 31st I killed the dog, and examined the intestinal canal (at 11.30 a.m.), which revealed the presence of sexually -mature living Trichinae. The males (of one of which I retain an accurate figure) displayed the characteristic bilobed caudal appendage, leaving no doubt as to their source and nature. I have mentioned the precise time of the experiment, in order to show that a period of sixty-nine hours proved amply sufficient for the development of the young muscle-flesh-worms of the human subject into the sexually-mature adult Trichinae of the dog. Exp. 24. With another portion of this human flesh (taken from the muscles of the tongue) in which the Trichinae were extraordinarily abundant, I fed a cat. In about ten days the animal showed the most marked symptoms of trichinosis. It refused to eat ; the eye lost its lustre ; the body became very thin, and I thought the animal would die. By very great care, keeping it warm before the fire, and subsequently inducing it to take a little milk, the creature improved, gained flesh, and eventually recovered. About three months afterwards I de- stroyed this cat, when on examining the panniculus carnosus, latissimus dorsi, and other superficial muscles, I found great quantities of well-developed, capsuled Trichinae. Although the animal had swallowed scarcely a quarter of an ounce by weight of the infested flesh, yet thousands of parasites had been pro- pagated, and dispersed throughout its muscular system. In this way the helminthiasis nearly proved fatal to my cat. As has been already stated, Dr Thudichum, who I believe had an opportunity of examining the corpse of this trichinised German, estimated the number of parasites in his body at 40,000,000. I do not think this estimate likely to be exag- gerated, for if all the flesh had been infested to the extent I found to obtain in respect of the muscles of the tongue, I believe 100,000,000 would have been nearer the mark. In places the point of a needle could scarcely be thrust between the capsules, so closely were they agglomerated. Exp. 25. From the 19th to the 25th of April, 1866, inclusive, 11 l(te PARASITES OF MAN daily administrations of trichinous pork, in the form of bolus, were made to a sheep by Mr Pritchard. The Trichinae were obtained from one of our experimental animals at the Veterinary College, about two ounces of the flesh being given at each feeding. The flesh of this sheep (destroyed in the following November) failed to give any indication of the presence of parasites. Exps. 26 and 27. About the same time, and occasionally at intervals extending over a period of five weeks, Mr Pritchard also fed two young fowls with the same trichinous pork. Towards the close of October, 1866, both birds died, when Mr Pritchard carefully examined the flesh of them, but failed to find " any trace of Trichinae. Exps. 28 and 29. From April 2nd to the 9th of the same month, 1866, inclusive, feedings with trichinous pork were likewise given to two dogs. These animals were destroyed and examined by Mr Pritchard in November, 1866, but the result appears to have been negative. It is perfectly certain that the infection of man by Tri- china is invariably due to the ingestion of verminiferously diseased meat, and as remarked in my ' Lectures/ whenever the parasites are taken in large numbers unpleasant symptoms soon show themselves in the infested person. There is, first of all, restlessness, loss of appetite, and more or less prostration. This is succeeded by rheumatoid pains in the limbs, with the frequent accompaniment of considerable swelling. The pain is not situated in the joints, but in the intermediate soft parts. In severe cases the limbs are drawn up and half bent, as in instances of severe and continued cramp. Sometimes the suffering is excruciating and unbearable, patients having been known to request the surgeon to put an end to their lives. In the worst forms of the malady death rapidly ensues from diarrhoea and exhaustion. If the parasites have gained admis- sion to the muscles all hope of destroying them is at an end ; but if a person suspects himself to have eaten diseased or trichinised meat he should lose no time in seeking professional assistance, seeing that the administration of suitable anthel- mintics might be the means of saving his life, whereas a few days' delay would probably prove fatal. So long as the worms remain in the stomach or intestinal canal they can be got rid of, but when once the trichinal brood have invaded the flesh then they cannot be expelled. As remarked in my ' Entozoa/ NEMATODA 163 it is easy to perceive that although, in the majority of instances, Trichiniasis does not cause death, yet the percentage of fatal cases is by no means insignificant. The notion that particular breeds of swine are more liable to be infested than others is absurd, since infection must be due to the facilities offered for swallowing garbage, especially dead rats. According to Drs Belfield and Atwood 8 per cent, of slaughtered American swine contain Trichinae. In infested hogs they found from 35 to 13,000 parasites in a cubic inch of muscle, and by repeated feedings they succeeded in rearing about 100,000 Trichinae in the body of a rat. In regard to the disease in man let us glance at the phenomena that presented themselves in Plauen, a town of Central Saxony. Drs Bohler and Konigsdorffer, who first saw this disease and treated it, state, according to Leuc- kart, that "the affection began with a sense of prostration, attended with extreme painfulness of the limbs, and, after these symptoms had lasted several days, an enormous swelling of the face very suddenly supervened. The pain occasioned by this swelling and the fever troubled the patients night and day. In serious cases the patients could not voluntarily extend their limbs, nor at any time without pain. They lay mostly with their arms and legs half bent heavily, as it were, and almost motionless, like a log. Afterwards, in the more serious cases, during the second and third week, an extremely painful and general swelling of the body took place ; yet, although the fifth part of all the patients were numbered amongst the serious cases, only one died." Satisfactory as it may be to note the numerous recoveries which take place, this circumstance is very much marred by the fact that a large proportion of the patients suffer the most excruciating agony. In the main it will be observed that Bohler's and Konigsdorffer's experience, as recorded by Leuckart, corresponds very closely with that given by other observers. The symptoms, moreover, are very similar to those produced in the original case published by Zenker. In this case, which occurred in the Dresden Hospital (1860), the patient was a servant girl, aged twenty, and the principal symptoms were loss of appetite, prostration, violent pains, contraction of the limbs, and finally oedema, which, in association, perhaps, wibh a certain amount of pneumonia, terminated her career within a period of thirty days. The post-mortem appearances showed 164 PARASITES OP MAN that the larval Trichinae were the cause of death. The intes- tinal canal contained numerous sexually-mature worms. The effects produced by Trichinae on animals are similar to those occasioned in man. The phenomena were summarised by Davaine (in the journals quoted below) in 1863 as follows : " The first phase is characterised by intestinal disorder, pro- duced by the development of the larvae in large numbers, and their adhesion to the mucous membrane of the intestine. In this stage M. Davaine has seen rabbits die with intense diar- rhoea ; one of two cats which he fed with trichinised meat had diarrhoea for at least a fortnight, but survived. Of five or six rats fed on a similar diet, one only, which was pregnant, died of diarrhoea, after abortion, on the eighth day. According to M. Leuckart, the passage of the embryos of Trichinae through the intestinal walls sometimes produces peritonitis. This intes- tinal phase often becomes blended with the next ; it may be relieved by the expulsion of the worms by means of the diar- rhoea, or may cease with the natural death of the worms. " The second stage presents general symptoms muscular pains, &c. These phenomena are dependent on the introduc- tion of the Trichinae into the muscles; they rapidly acquire their maximum intensity, and have not a long duration. The appearance and duration of this stage are in complete relation with the development and length of sojourn of the Trichinae in the intestines ; in fact, in this entozoon, oviposition is not slow*" and of long duration, as in many nematoid worms ; the genital tube is rapidly formed, and the ova, in its whole length, are developed almost simultaneously, so that the embryos, arriving soon at maturity, are at once thrown out in large numbers into the intestine, and the mother Trichina dies exhausted. If it be remembered that the embryos do not escape before the eighth day, that a certain number of days are required for their arrival in the muscles, and that new ones are not produced after six or seven weeks, it will be understood that the first symptoms of this stage can scarcely appear until the end of a fortnight after ingestion of the diseased food, that they must continue four or five weeks, and that after this they may dis- appear. This course of events is observed in animals ; and in man the symptoms of this stage have shown themselves and become aggravated from the third to the sixth week after infection. Most animals die during this stage ; rabbits rarely survive ; rats, on the contrary, generally resist it. NEMATODA 165 " If the animals do not die of the general symptoms or local disturbances proper to these two stages, the inflammatory sym- ptoms cease, respiration becomes natural, and order is re-esta- blished. But, in some cases, the number of cysts formed in the muscles are sufficiently great to impede them in the proper exercise of their functions, and hence arises general debility, a kind of consumption which persists or becomes aggravated, and the animal dies of marasmus. M. Davaine has noticed this in rabbits, but especially in a rat. " Recovery from these phases of trichinal infection may be apparently perfect. A rabbit which M. Davaine kept during five months became large and fat, although it had a large number of Trichinae in its muscles ; a rat which had had these entozoa in considerable numbers during six months was, to all appearance, in good health. Hence he concludes that the Trichinae produce symptoms only when they are in the intes- tinal canal, and when they are entering the muscles. Having become lodged in their cysts among the muscular fibres, they may remain harmless for an indefinite time. In every case except one, down to 1859, Tri chinas have been found in the bodies of persons who have died of disease (generally chronic) or by accident ; or in the dissecting-room, in bodies regarding which the previous history could not be obtained. In most cases the cysts contained a cretaceous or fatty deposit, showing that they had probably existed several years. " The observations which have been made on the human subject, in regard to the symptoms caused by Trichinae, show that they belong, as in animals, to the initial period of infec- tion. They consist in intestinal and in muscular lesions ; the latter coincide with the entrance of the parasite into the muscles, and are truly traumatic. In Zenker's case the intestinal symptoms were swelling and pain ; in a case described by Friedreich diarrhoea was present. In all cases the most remarkable symptoms were violent rheumatoid pains in the muscles, not in the joints, which were considerably aggravated by attempts to extend the half-bent limbs. The other sym- ptoms have been variable, but have had a strong resemblance to those of typhoid fever. In several cases there has been abundant sweating ; and in one there was a very remarkable miliary and furuncular eruption. The animal heat was dimin- ished in Friedreich's case ; and in those observed in Voigtland by Freytag the temperature never exceeded 102 Fahr. 166 PARASITES OF MAX " The progress, duration, and severity of the disease in man are in relation to the number of Trichinae taken into the digestive canal. Of sixteen patients observed at Plauen by Drs Bohler and Konigsdorffer, eight, who were moderately affected, recovered in a month ; four, more severely diseased, were ill two months ; of four others, one died with ascites and colliquative diarrhoea at the end of two months, and three recovered slowly at the end of three or four months. Recovery does not imply the death of the Trichinae, it follows their enclosure in cysts. " The diagnosis of trichinal infection has several times been made in the living human subject by removing a portion of muscle. M. Davaine thinks it probable that, during the first six or eight weeks of the disease, the diagnosis may be con- firmed by searching for adult Trichinae in the alvine evacuations, produced naturally or by means of a purgative. " The prophylactic treatment consists simply in the avoidance of uncooked meat. The medicinal treatment must vary with the stage of the disease. At first, attempts must be made to expel the parasites from the intestines by purgatives and anthelmintics. Which amongst the latter is the most energetic is not yet determined. Calomel is, perhaps, M. Davaine thinks, the best. After six or eight weeks all treatment directed towards the intestines is superfluous. It is scarcely probable that any substance will act on the larvae disseminated through the muscles. Friedreich has recommended picronitrate of potash ; but, in the case in which he used it, live Trichinae were found in the muscular tissue after the patient was con- sidered to be cured/' In regard to the possibility of curing trichiniasis by the administration of drugs which should act as trichinacides upon the parasites in the condition of flesh-worms, the absurdity of the proposal only equals that which was made in reference to the destruction of hydatids by the administration of katnala. As has been shown in the record of my first experiment the flesh of a trichinised corpse may be thoroughly saturated with a strong solution of chloride of zinc, and yet the worms will remain quite unaffected. In reference to the dangers arising from the consumption of diseased meat, Professor Gamgee has very cogently put two questions : " Did Moses know more about pigs than we do ? }> " Was it a knowledge of the parasitic diseases of swine and man NEMATOBA 167 that led Moses to condemn pork as human food ? 3> Mr Gamgee answered both questions negatively, thus : " The wisdom of the Mosaic law can only be justly estimated with a knowledge of the accidents arising in warm countries from eating pork throughout long and hot periods of the year ; and there is no doubt that the direct evil results, as manifested by human sickness, led to the exclusion of pork from the list of Israelitish viands. The masses of measly pork which may be seen hanging from the butchers' stalls in Southern Europe prove that the long-legged swine which hunt the forests for acorns, and rove about to pick up all kinds of offal, are often unfit for human food, and that they were so to no less extent in the land of Israel is probable." As supplementing Pro- fessor Gaingee's argument, I may remark that, if Moses had been furnished with special knowledge beyond that of his con- temporaries, he would not, in the matter of meat-parasitism, have confined his restrictions to pork. Had he possessed any knowledge of measly beef, he would not have spared the ox on the ground that although " it divideth the hoof, yet it cheweth the cud." As regards home-reared animals, Professor Gamgee cogently remarked : ' ' It is interesting to observe that parasitic maladies in the pig specially abound in that section of the United Kingdom where swine live most amongst human beings. The Yorkshire and Berkshire pigs, in their native counties enclosed in the farmyards of their breeders, are free from worms which are likely to live in the body of man. The Irish pig is the one most commonly injured by entozoa, and the reason for this is evident when we know how much the cottager relies on rearing a porker which is permitted the free range of house and road, where every description of filth is devoured, charged with the ova of parasites expelled by man or some of the lower animals/' He also adds : " The conditions under which we live in the British isles are certainly much less favorable to the propagation of worms ; but we disregard, in our ignorance, the most common precautions to protect ourselves from loathsome diseases, and not only permit dogs to eat any kind of offal in and around slaughterhouses, but sanction the existence of piggeries where all kinds of garbage, charged with worms or their eggs, are daily devoured by swine. The majority of germs calculated to engender parasites are to be found in abundance in the contents of the alimentary canal of human beings and domestic quadrupeds. If pigs are permitted to eat 168 PARASITES OF MAN these, as in Ireland or in many British piggeries, we must expect hams, bacon, and pork sausages to be charged with the embryonic forms of human entozoa. Whereas in Iceland the dog is the victim of human negligence, and en revanche the cause of human disease, in the British isles the pig holds this unenviable position. We have good reason to believe, with Moses, that the pig is an unclean beast ; but without discarding him from the scanty list of animals to be eaten, it is evident that we can purify the race of swine, and thus prevent human as well as porcine maladies." On the authority of Rupprecht, as quoted by Davaine, I append a list of the principal epidemics observed in Germany during the first six years immediately following the discovery of trichinosis : 1. Two slight epidemics in 1860 in the Island of Riigen ; 10 to 20 patients (Dr Landois). 2. An epidemic at Stolberg, 1860 (Dr Fricinus). The number of trichinised persons was not stated with certainty. 3. Five epidemics during five summers, 1858 to 1862, at Magdebourg. The number of patients was 300, two only died (Dr Sendler). 4. An epidemic at Plauen in 1862, 20 patients (Bohler). 5. Gusten, 1861, 40 cases, all cured (Frankel). 6. Epidemic in the Province of Armsted (Mansfeld), 1861, 8 patients. 7. Hettstadt, January and March, 1862, 8 to 10 patients. 8. Blankenburg, 1862, 278 cases, 2 deaths. 9. Calbe (Prussia), 1862, 38 cases (9 men, 25 women, 4 children), 8 deaths (Dr Simon and Dr Herbst). 10. Burg, in Magdebourg, 1863, 50 patients, 10 deaths (Dr Klusemann). 11. Quedlinburg, 1863, 9 patients, 1 death (Dr Behrens). 12. Plauen, 1863, 21 patients (Konigsdorffer) . 13. Falkenstein, 1863, 4 patients (Drs Bascher and Pinter). 14. Posen, August and September, 1863, o7 patients (Dr Samter). 15. Hamburg, 1863, 2 patients (Dr Tiingel). 16. Blankenburg, 1863, 32 patients, 2 deaths; new cases in 1864 (Dr Scholz). 17. Hettstadt (Prussian- Saxony), October, 1863, 158 patients, 27 deaths (Rupprecht). 18. Eisleben, December, 1863, and January, 1864, 18 cases, NEMATODA 1 69 no deaths. This result was attributed to the employment of phosphoric acid (Kupprecht). 19. Hettstadt, February and March, 1864, 8 patients, no deaths. Two cats were also attacked, one of which died. Nearly 50,000 Trichina were counted in an infected leg of pork (Kupprecht) . 20. Quedlinburg, 1864, 120 patients, 2 deaths; benzine was employed (Dr. Wolf). 21. Hettstadt, January, 1865, 15 patients (Rupprecht) . 22. Berlin, 1864, 3 cases (Dr Cronfeld). Several butcher boys (Frischer). 23. Leipzig, 1864, 14 patients, 2 deaths ; 4 were infested after having eaten raw beef hashed on a block which had previously received the flesh of a trichinised hog (Dr E. Wagner). 24. Potsdam, 1864, 5 slight cases (Dr Mollendorf ) . 25. Celle (Hanover), 1864, 8 patients (Dr Scheller and Dr Baring) ; Trichina proven in the pork by Gerlach. In 1855, 12 Trichina (?) patients were treated by Schuchart. 26. Hedersleben, 25th October, 1865, a pig was killed and sold ; on the 28th the malady appeared amongst the workmen ; 350 patients, 100 deaths. Of 100 children infected, none died. Trichina found in the autopsies (Dr F. Kratz). Dr Davaine also adds the following outbreaks : In Massachusetts, 1867, 6 patients from having eaten raw ham, 1 death (' Medical Times/ 20th April, 1867, p. 431). Eavecchia (Bellinzona), 1868, 5 patients, 4 deaths (Dr Zang- ger (in Landbote of Winterthur). Up to a comparatively recent date no case of trichinosis had been recognised in England during the life of the victim. As regards diagnosis, what was happening every day on the Con- tinent was utterly unknown here. Whilst, however, not a single instance of Trichina- disease had been observed by British physicians in actual practice, as many as thirty or forty instances had occurred where the parasites in question had been found post mortem. I had myself examined the trichinised flesh taken from a dozen of these corpses, but in no instance had the faintest suspicion of trichinosis been entertained during life. The circumstances attending the only outbreak of tri- chiniasis that has been witnessed in England are very inter- esting. In the month of April, 1871, I received from Dr W. L. Dickinson, of Workington, Cumberland, specimens of pork which he requested me to examine ; and in complying with 170 PARASITES OF MAN his request I confirmed his opinion that the diseased meat was infested with Trichinae. A few days afterwards I announced the discovery in the pages of the ' British Medical Journal' for April 22, p. 435. It happened, also, that at the time I was delivering a course of lectures before the Society of Arts ; consequently, in my second discourse (which was devoted to the parasites of cattle) I gave full details of the facts that were obtained. Taking a small portion of the flesh which I judged to be affected to an average extent I addressed the audience as follows : " If you calculate from one portion only, you might, if you had stumbled upon a part which was more infested with parasites than another, be led to over-estimate the degree of trichinisation. Taking proper precautions I have calcu- lated that one scruple of this trichinous flesh would give us 4320 parasites, and two scruples would therefore, yield 8640. Without speaking so precisely to numbers, I do not hesi- tate to aver my belief that there are at least 5000 of these parasites inside this small piece of ham. The number is pro- bably close upon 8640. In one drachm that would give us 12,000, and in an ounce 103,000, according to the old apothecaries' weight. If, however, we calculate according to the ordinary weight used by butchers, we should say that one ounce contains 43 7g grains of meat, and therefore the number of parasites in one ounce would be 85,000. Thus, in one ounce of meat from this particular pig you have 85,000 Trichinae, calculated at the rate of 200 in the grain, for I have purposely cut off the odd numbers. You may say, if a person can survive 18, 20, 30, or 40 millions, he would not take much harm from eating a piece of flesh containing only 8640 parasites. Such a portion, however, would be quite sufficient to make any one of us extremely uncomfortable were we to eat it, for supposing its contained parasites to be alive, it might prove dangerous to life. Why ? The explanation is this : Half of those 85,000 parasites, at the very least, will, in forty- eight hours after ingestion, have become fully-developed females ; and from each of these 42,000 there will proceed at least 1000 as a brood, so that the entire progeny (and it is they that do the mischief by their independent migrations through our tissues) will eventually yield about 42,000,000 entozoa. If we should be so voracious as to eat a pound of such trichinised flesh, then there would be 400,000,000 as the result of a single meal. NEMATODA 171 " Having detailed these facts and inferences, I now wish to bring to your notice some other particulars connected with the Cumberland outbreak. " Dr Dickinson, of Workington, tells me that he was at first suspicious that his patients were suffering from fever, but was not quite able to make out what the disorder was. At length certain symptoms occurred, which suggested that it might possibly be the German flesh-worm epidemic making its appear- ance in this country for the first time, and, therefore, in view of verifying the facts of the case, he sent me portions of the flesh of the pig. He describes the symptoms, which in their character corresponded with those previously recorded as experienced by persons similarly attacked. Dr Dickinson remarks, towards the close of his communication, that the victims form a small family who have carefully reared their own swine. The British farmer is thus here introduced to us at his own table playing the part of ' host' at her own table, I should say, for, to be more pre- cise, it is a widow, her daughter, and a man-servant who are suffering. Dr Dickinson informs me that for two or three weeks before he was called to see them they had been eating sausages and boiled pork from one of their own home-fed pigs, which pig, by the way, turns out to have been an old sow. He brought away some sections of the leaner portions of the flesh for microscopic examination. You will observe that there can be no mistake about the source of the food on this occasion. Hitherto, Trichina has not been observed in our British-fed swine in more than one or two, or possibly three instances. Therefore it would be very interesting to ascertain how it hap- pened that this poor pig became trichinised. In my communi- cation addressed to the 'British Medical Journal/ I wrote as follows : " Dr Dickinson has at the present time under his care a family suffering from the so-called flesh-worm disease, resulting from the consumption of ham prepared from pigs reared by the family themselves. A portion of ham sent to me swarmed with recently encapsuled Trichinae. Dr Dickinson being thus the first person who has diagnosed trichiniasis in the living subject in England, I hope he may be induced to give us further particulars/ The editor, in commenting upon this letter, added a practical point, which I wish especially to bring to your notice. He says : ' The subject of parasitic diseases of domestic animals is one of widespread and increasing interest. 172 PARASITES OF MAN It is immediately related to the irrigation of fields with sewage/ The editor, of course, made this statement on independent grounds, and on his own responsibility. If he had said the subject bears an indirect relation to the sewage question, he would have said no more than is abso- lutely true, for, as I shall take occasion to explain, there is every reason to suppose that certain forms of parasitic disease may be propagated by means of sewage. In this connection some of you may be disposed to ask the question : f Are there any sources of comfort to be gathered from the facts V Or you may say, supposing that in future our British swine are not as free from Trichinae as they have been hitherto, can we possibly avoid the contingency of playing the part of host to those crea- tures ? Certainly, I reply, it is simply a question of properly cook- ing the food. If these farmers have not cooked their food at all, or scarcely at all, that will at once account for their being laid up. I should tell you that the lady and the daughter are recovering, and that they are convalescent, but the man-servant is very ill. If, during cooking, the flesh consumed by these persons had been raised to a persistent temperature of 170 Fahr., then, doubtless, the ingestion of trichinised pork would have done no harm. You observe that Dr Dickinson says in his letter that they partook of it roasted and boiled. Now, few of us are in the habit of eating underdone pork, although there are other meats that we devour very readily in an imperfectly cooked state. It must be remembered, also, that although the exterior may have been subjected to a temperature of 212 degrees, it by no means follows that the whole of the joint throughout must have been submitted to that temperature. Under rapid cooking, the centre of a large joint may remain much below even 140 degrees. If the man-servant ate only one ounce of the flesh with living Trichinae in it, he will probably have at this present moment at least 42,000,000 of these guests in his muscles. You will ask, ' Will he recover ?' ' Yes ; if he ate no more than that/ If he has eaten 2 oz. thoroughly underdone, depend upon it he has 80,000,000, and if he has eaten 3 oz. he will have over 100,000,000 of Trichinae in his muscles. Could he survive if he had eaten over 3 oz., and thus have 100,000,000 and upwards of these inhabitants ? I think he could. We have evidence on this point from the case in which I estimated that there were upwards of 100,000,000 of Trichinae present, and yet the man survived the attack. NEMATODA 173 " Incidentally I may remark that in the course of the last twenty years, although millions of parasites and their eggs have passed through my hands, I have almost entirely escaped infec- tion. It is something to know what you are either handling or looking at, because there are many parasites besides Tri- china which are dangerous. There are gregariniform entozoa residing in meat which we eat every day without any bad consequences. They are as harmless as cheese-mites. There is no need to be in the slightest degree nervous about flesh- food, provided it is properly cooked. I believe there will be no fatal issue in the case of any of the three individuals just alluded to, but the chief practical point before us arises out of the fact that we have here, for the first time in England, an epidemic of trichiniasis. By calling attention to the subject, it will, to say the least, suggest precautions by which future epidemics may be avoided." The above remarks form the substance of a lecture given on the 24th of April, 1871. A week later I delivered the third of the Cantor lectures for that year, when I took occasion to add the following particulars : " It has been asked whether the so-called muscle-Trichinae, after they have arrived at their destination within the flesh of man, are capable of producing any more unfavorable con- sequences ? The answer is, Certainly not. In the case of man it would be necessary that his muscles should be eaten in order for the Trichinae to become sexually-mature worms; and in those countries where cannibalism exists, the man- eater would himself become trichinised, and would certainly deserve his fate. I was very desirous to follow up the account of this outbreak by inquiries respecting the particular animal which had been the cause of the outbreak. I may therefore mention that my informant, Dr Dickinson, states that the family, including the man-servant, all fed together, and that they had for upwards of a fortnight eaten daily, and some- times twice a day, sausages made from the flesh of the trichi- nised animal. And he adds : The meat cut from the ham and flitches, and what is called the spare-rib, was roasted before the fire or in the frying-pan. Occasionally it was cooked in the oven. Dr Dickinson ascertained from the mother that she liked her meat to be underdone, and thus, therefore, there is very little doubt that the meat was generally undercooked. The man, a strong labourer, had a good appetite, and would 174 PARASITES OF MAN therefore get a large share. He is improving slowly. Dr Dickinson adds in a postscript, what is still more to the point, that the sausages would be most likely undercooked ; they would be cooked in the frying-pan, and if only brown on the outside would be eaten. It is probable that the outbreak was due therefore to eating underdone meat from this pig, cooked in various ways, and not alone from the ham itself." If the facts connected with this outbreak be honestly faced, it must be rendered clear to any unprejudiced observer that Dr W. Lindow Dickinson was the first person to observe, recognise, and treat the Trichina disorder in this country. No other English, Scotch, or Irish physician has encountered any similar case. If I lay stress upon this fact it is because I have learned from Dr Dickinson that another person has asserted priority in this relation. Sir Dominic Corrigan is stated to have told a gentleman in the House of Commons, "that he had often met with trichiniasis in his practice in Dublin," further averring that the disease " was quite common in many parts of Ireland." If Sir D. Corrigan merely desired it to be understood that he had repeatedly encountered the Trichina at post-mortem examinations, then there is nothing surprising in his statement, but if, on the other hand, the dis- ease itself has been frequently recognised in the living Irish human subject, one can only express astonishment that hitherto no single instance of the kind appears to have been recorded either in the public or professional journals. BIBLIOGRAPHY (No. 21). English Literature. Allman, 0. /., " Exhib. of Specimens," ' Micr. Jrn. and Structural Record/ 1842, p. 94,.Althau8, J., 'Essay on Trichinosis/ London, 1864. Idem, "On a Suspected Case," 'Med. Times and Gaz./ 1864, p. 161 ; see also pp. 362 and 390. Atwood, see Belfield. Ballard, E., " On Diseased Meat," ' Med. Times and Gaz./ 1864. Bel- field (with Atwood), "Trichinae in Pork;" 'New York Med. Rec./ Dec. 28, 1878 ; ' Med Times and Gaz./ Feb. 15, and ' Lancet/ Feb. 22, l87$.Bellingham, 0. ., 'Dublin Med. Press/ 1852. Bowditch, H. J., " Cases of Trichina," 'Boston Med. and Surg. Journ./ 1842-43-44. Bristowe, J. 8. (and Rainey), 'Trans. Path. Soc./ 1854. Chevers, N., " Sanitary Efforts in regard to Trichiniasis," 'Lancet/ 1864, vol. ii, p. ISS.Colbold, T. S., "On the Discovery of Trichina, in relation to the question of Priority," 'Lancet' for March 3, 1866, p. 244. Idem, 'Parasites, and the part they play in the Economy of Nature' (lecture), Manchester, NEMATODA 175 1873, p. 46 ; also in the ' Veterinarian/ March, 1874. Idem, Eemarks in the ' Journ. Soc. of Arts/ 1866, p. 399; also in 'Med. Times, and Gaz./ 1867, p. 24; also in ' Lancet/ Feb., 1864 and 1866, p. 538. Idem, ' Our Food-producing Kuminants and the Parasites which reside in them' (Cantor Lectures), 1871. Idem, "Experiments with Trichina/' ' Proceed. Linn. Soc./ vol. ix, p. 205, 1867; see ' Lancet ' for Jan. 13, 1866, p. 52; 'Brit. Med. Journ.' for Dec. 22, 1866, p. 713; also < Lancet' for Jan. 9, 1867, p. 91. Idem, "Worms" (I.e., Bibliog. No. 2, Lecture xviii), 1872. Idem, " Outbreak of Trichinosis in England," ' Brit. Med. Journ./ 1871, p. 435. Idem, " Trichinae in Fish " (alleged to have been found in a pike by Dr. Elendenen at Ostend), in the ' Lancet' (anonymous annotation) for Nov. 16, 1878. Curling, T. B., two cases, ' Lond. Med. Gaz./ 1836.Davaine, 0., quoted in < Brit. Med. Journ./ see foreign lit., below. Delpech, abstr. of his Report, 'Brit. Med. Journ./ 1866, p. 375. Dickinson, W. L., 'Brit. Med. Journ./ 1871. Elendenen, "Trichinae in Fish" (newspaper report respecting his " find") ; see Cobbold, above. Farre, A., "Observations," 'Lond. Med. Gaz./ 1835-36. Friedreich, N. (trans, by Ogle), 'Med.-Chir. Rev./ 1863, repr. in ' Edin. Vet. Rev./ 1863. Furstenburg, < Edin. Vet. Rev./ 1864, p. 513. Gordon (see Chevers). Gamgee, J., "On Diseased Meat," 'Pop. Sci. Rev.,' 1864. Goodsir, J. t ' Month. Journ. Med. Sci./ 1842. Harr, ' Bost. Med. and Surg. Journ./ 1866, p. 532. Harrison, " On a peculiar Species of Entozoon occasionally found in the Voluntary Muscles of the Human Subject," ' Rep. of Brit. Assoc./ Aug. 12, 1835 ; in ' Dub. Journ./ vol. viii, 1835-36 ; in ' Lond. and Edin. Phil. Mag./ and in ' Amer. Journ. Med. Sci./ vol. xviii, p. 187, 1836. Herbst, "Trichinae in the Badger," 'Assoc. Med. Journ./ 1853, p. 49 J. Hilton, J., "Notes on a peculiar appearance observed in Human Muscle, probably depending upon the formation of very small Cysticerci," 'Lond. Med. Gaz./ vol. xi, p. 605, 1833. Jackson, J. D., "Trichi- niasis," in ' Hay's Amer. Journ./ 1867, p. 82. Kiefer, H., cases, 'Bost. Med, and Surg. Journ./ 1866, p. 208. Kobelt, 'Micr. Journ. and Struct. Rec./ 1842, p. 147. Kratz, " On the Heder- sleben Epidemic," ' Brit. Med. Journ./ 1866, p. iQ.Krombein, " Trichiniasis in New York," 'Amer. Journ. Med. Sci./ 1864, and ' Med. Times and Gaz.,' 1864, p. 292. Kiichenmeister, F., Symptoms, &c., 'Lond. Med. Rev./ 1860, p. 457. Langenbeck, case, ' Edin. Vet. Rev./ Feb., 1864. Leidy, J., " Trichina in 176 PARASITES OF MAN the Pig/' ' Annals of Nat. Hist./ and ' Pr. Ac. N. S. Philad./ 1847. Leuckart, R. (translations from), in ' Ann. Nat. Hist./ 1860; in ' Qrt. Journ. Micr. Sci./ 1860; and in ' Bost. Med. and Surg. Journ./ vol. liii, p. 198, 1860-61. Liveing, R., "Path. Soc. Rep." in ' Med. Times and Gaz./ 1865, p. 374. Hosier, "On Trichinous Flesh/' 'Brit. Med. Journ./ 1864, p. 554. Idem, " On Benzine in Trichinosis/' ( Med. Times and Gaz./ Oct., 1864, p. 444. Nunneley, T., ' Brit. Med. Journ./ 1866, p. 252. Owen, R., " Description of a Microscopic Entozoon infesting the Muscles of the Human Body," 'Proc. Zool. Soc./ and ' Lond. Med. Gaz./ 1835; ' Trans. Zool. Soc./ vol. i, 1835. Idem, Remarks in ' Journ. Soc. of Arts/ 1866, p. 399. Paget, J., " Letter relating to the Discovery of Trichina/' 'Lancet/ March, 1866, p. 269. Rorie, J., Letter, 'Lancet/ Feb., 1864. &///*- bwy, J. H., On a supposed Species of Trichina (T. cystica) from the Human Bladder ; in his paper on " Parasitic Forms," in ' Hay's Amer. Journ. Med. Sci./ 1868, p. 376. Sanders, R., ' Edin. Month. Journ./ 1853. Sawer, A., 'Bost. Med. and Surg. Journ./ 1865, p. 16. Sutton, G., Report on Trichinosis; Indiana, U.S., 1874. Thudichum, J. W. S., 'Brit. Med. Journ./ Jan., 1864, repr. in ' Glasgow Med. Journ./ April, 1864, p. 116; also letter in 'Edin. Med. Journ./ Feb., 1864. Idem, " Rep. on the Parasitic Diseases of Quadrupeds used as Food/' pub. by the Med. Officer of the Privy Council, London, 1865. Idem, "The Diseases of Meat as affecting the Health of the People," ' Journ. Soc. of Arts/ April 20, 1866. Idem, "German Sausages and the Trichina Disease," 'Scientific Opinion' for April 25, 1866. Idem, 'Lancet 'for Jan. 6, 1866, p. 16. Turner, W., "On the Trichina spiralis," 'Edin. Med. Journ./ Sept., 1860; in the ' Year-Book/ p. 109, for 1860; in 'Med.-Chir. Rev./ 1862; and in 'Bost. M. and S. Journ./ vol. Ixiii, p. 294. Ude, "Rep. on the , Inspection of Pigs," ' Med. Times and Gaz./ Aug., 1868, p. 141. Valentin, 'Micr. Journ. and Struct. Rec./ 1842, p. 87. Virchow, R., Extr. from his brochure on 'Trichina* (by myself), in 'Gunther's Record 'for 1864, p. 611. Idem, "On the Cure of Trichinosis," 'Brit. Med. Journ./ April, 1866, p. 368. Idem, from " Comptes Rendus," in 'Qrt. Journ. Micr. Sci.,' 1861. Idem, from his 'Archiv/ 1860, Bd. xviii, Heft. 4, p. 330; in 'Brit, and For. Med.-Chir. Rev./ vol. xxvi, p. 515, I860. Wedl, Report, 'Brit. Med. Journ./ Dec., 1866, p. 618. Will;*, 8., " Letter respecting the Discovery of Trichina," ' Lancet,' NBMATODA 177 March 10, 1866, p. 269; see also the ' Times/ Feb. 13, 1866. Windsor, /., ' Brit. Med. Journ./ March 4, 1866, p. 319. Wood, H., case, ' Lond. Med. Gaz./ 1835. Foreign Literature : Ardenghi, E., " Sulla Trichina spiralis," 'Lo Studente Yeterinario/ 1876, p. 115. Behrens, " Bin Fall von Trichiniasis," ' Deutsche Klinik/ No. 30, 1863 (quoted by Davaine).- Bette, F., ibid., 1876. Bis choff, 'Path. Anat. des menschl. Korp./ 1845. Idem, ' Med. Annalen/ 1840. Bohler, 'Die Trichinenkrankheit in Plauen/ 1863. Boudin, "Des epidemies de Trichina spiralis observees en Allemagne dans ces dernieres annees," ' Journ. de Med. Yet. Milit./ August and September, 1864 (quoted by Davaine). Glaus, ' Wurzb. nat. Zeitschr./ 1860. Idem, ' Ueber die Trichine ' (a discourse), 1877. Oolberg, 'Deutsche Klinik/ 1864. Davaine, 0., ' Traite' (1. c., Bibl. No. 1), 1860, p. 672, 2nd edit., p 732 768. Idem, " Faits et Considerations sur la Trichine," ' Memoires de la Societe de Biologie' for the year 1862, torn, iv, ser. 3, 1863; in 'Gazette Medicale de Paris/ 1863; in 'British Medical Journal ' for April 25, 1863 ; and in my ' Entozoa/ p. 349. Idem, "La Trichine" (popular exposition), in ' Eevue des Deux Mondes ' for May, 1865. Dujardin (1. c., Bibl. No. 1), p. 24. Fiedler, ' Virchow's Archiv/ 1864. FlecUes, F., ' Die Trichinen und die Trichinenkrankheit ' (popular exposition), Prag., 1866 (quoted by Davaine). Friedrich, N., 'Virchow's Archiv/ 1862. Furs tenb erg, " Wochenblatt d. Ann. der Landwirthsch., in d. Konigl. Preuss. Staaten," 1865. Gerlach, C., 'Die Trichinen, M 866. Idem, ' Hanno- versche Zeitschrift/ 1864. Hagen, in ' Pharmaceutische Centralhalle/ 1862. Henle, 'Muller's Archiv/ 1835, s. 526. Herbst, ' Nachrichten v. d. Georg-Aug. Univ. zu Gottingen/ 1852; 'L'lnstitut/ 1852, p. 135. Eeschl, E. L., 'Ueber Trichinen, die Trichinenkrankheit und die Schiitzmassregeln dagegen/ Gratz, 1866 (quoted by Davaine). Kestner, "Etude sur le Trichina," ' Gaz. Med. de Paris/ 1864. Klusemann, " Die Erkrankung durch den Genuss von Nahrungsmittel aus dem Thierreiche," 'Deutsche Klinik/ 1864. Kobelt, 'Valentin's Repertorium/ 1841. Krabbe, " Husdyrenes Indvoldsorme," ' Tiddsskrift for Yet./ 1872,Kratz, ' Die Trichinenepidemie zu Hedersleben/ 1866. Kuchenmeister, ' Parasiten/ 1855.^ Leuckart, ' Untersuchungen ueber Trichina spiralis,' 1866. - Idem, " Die mensch. Par./ Bd. ii, s. 409. Idem, " Die neuesten Entdeckungen ueber menschliche Eingeweidewiirmer 12 178 PARASITES OF MAN und deren Bedeutung f iir die Gresundheitspflege," ' Unsere Zeit./ 1862. Lion, ' Zur Geschichte, Therapie, Prophylaxis, und Sanitatspolizei der Trichinen' (quoted by Pagenstecher) . Luschka, " Zur Naturgeschichte der Trichina spiralis/' * Zeit- schr. fiir wissenschaftl. Zool./ 1851. Meissner, ( Zeitschr. f. rat. Med./ 1855. Idem, " Ueber Trichinenkrankheit," ' Schmidt's Jahrbiicher/ 1863. Ordonez, E. L. t 'Note sur la Distinction des Sexes et le Developpement de la Trichina spiralis des Muscles/ Paris, 1863 ; and ' Compt. Rend. Soc. Biologie/ p. 61, 1863 (quoted by Davaine). Pagenstecher, ' Verhandl. d. Natur- hist.-Med. Vereins zu Heidelberg/ 1864. Idem (und Fuchs), ' Die Trichinen/ 1865. Perroncito, "La Trichina spiralis" in ' Italia. Estr. degli Annali R. Accad. d'Agric. di Torino,' vol. xx, 187*7. Reyher, 0., ( Die Trichinenkrankheit/ Leipzig, 1862. Rodet, H., ' De la Trichine et de la Trichinose/ Paris, 1865 (quoted by Davaine). Rupprecht, B., 'Die Trichinenkrankheit im Spiegel der Hettstedter Endemie betrachtet/ Hettstedt, 1864. Seidel, ' Jenaische Zeitschr. f. Med. u. Nat/ 1864. Siebert, f Ueber die Trichinenkrankheit und ihre Vermeidung/ Jena, 1863 Siebold, art. " Parasiten," 'Wagner's Hand- worterbuch/ 1844. Simon, O., "Eine Trichinen-epidemie in Calbe," 'Preussische Medicinal Zeitung,' 1862. Tommasi, ' La Trichina spiralis e la Malattia prodotta da esso/ Torino, 1863. Tilngel, ' Archiv von Yirchow/ xxvii, 3, 421, 1863 (quoted by Davaine). Virc h ow, 'Deutsche Klinik/ 1859; ' Cornptes Rendus de 1'Acad. des Sci./ torn. xlix. Idem, ' Archiv f. Path. Anat. und Physiol./ Bd. xviii. Idem, ' Dars- tellung der Lehre von den Trichinen ' (fur Laien und Aerzte), 1864. Vogel, ' Die Trichinenkrankheit/ 1864. Wag- ner, " Eine Trichinenepidemie in Leipzig/' ' Arch, der Heil- kunde/ 1864. Wunderlich, C. A., " Sur la diagnose probable de 1'affection trichinale," 'Gaz. Med. de Paris/ p. 311, 1863 ; ' from ' Wagner's Archiv der Heilkunde/ ii, 3, p. 269, Leipzig, 1861 (quoted by Davaine). Zcnlter, " Zur Lehre von der Trichinenkrankheit," ' Deutsches Archiv. fiir Klin. Med./ Bd. viii, s. 387. Idem, 'Virchow's Archiv/ 1855 and 1860. Trichocephalus dispar, Rudolphi. This well-known worm possesses a long filiform neck, occupying about two thirds of the entire length of the body. The surface of the skin though smooth to the naked eye is furnished on one side with a longi- tudinal band of minute wart-like papillae. The tail of the male NEMATODA 179 is curved, and emits at the extremity a short, tubular penis- sheath, armed with minute retroverted spines. The tail of the female is straight and bluntly pointed. The eggs measure 5^" to ~" in their long diameter. The whipworm infests the cascum, and also the upper part of the colon. Upwards of one thousand were found by Kudolphi in a woman. The original name of Trichuris, given to this worm by Buttner, could not, of course, be allowed to stand when it became evident that the so-called tail was in reality the head and neck. The Trichocephalus is not uncommon in England and Ireland. It is less frequent in Scotland. On the continent, however, it is so abundant that M. Davaine calcu- lates that not less than one half of the inhabitants of Paris are infested by it. From what Dujardin has said it can be scarcely less abundant in Northern France, for M. Duval, the distinguished director of the Eennes School of Medicine, supplied that helminthologist with numerous specimens on various occasions. The worm abounds in Italy and Egypt ; being scarcely less prevalent in the United States. The lamented Mr Noel, one of my old pupils at the Middlesex Hospital College, brought me specimens which he found post- mortem on three or four occasions. Dr Haldane, of Edinburgh, once or twice obtained large numbers (post-mortem). In Ireland, Bellingham found the worm in eighty-one out of ninety post-mortem examinations. Mr Cooper, of Greenwich, met with it, post-mortem, in eleven out of sixteen instances. When treating patients for tapeworm I have repeatedly expelled the whipworm. The organisation of Trichocephalus dispar has been investi- gated by Dujardin, Mayer, Yon Siebold, Eberth, Bastian, and others. Prof. Erasmus Wilson and myself have carefully studied the anatomy of the closely-allied whipworm of ruminants (T. affinis) which is discussed in my ' Entozoa/ The statement of Kiichenmeister that there ,re no external appendages in the female Trichocephalus comparable to those known to exist in the allied Trichosomata, is incorrect. Leuc- kart's, and especially Virchow's, researches disproved Kiicheii- meister's and Meissner's notion that Trichina were the young of Trichocephalus. The experiments of Davaine render it probable that the young get into the human body in a direct manner. He finds that the eggs undergo no development whilst yet lodged within the host's intestines. The eggs are 180 PARASITES OF MAN expelled per anum in the immature condition in which they first escape from the body of the parent worm. It further appears that, after their expulsion, a period of six months must elapse before embryonic formation commences. The fully-developed embryo measures g" in length, and resembles the parent to a certain extent. Whipworms rarely put their bearers to inconvenience; never- theless, both human and animal hosts occasionally suffer from their presence. Thus, Felix Pascal quotes a remarkable and fatal instance of cerebral symptoms from this cause in a girl of four years of age ; and Mr Gibson has recorded an instance in which these worms produced paralysis and loss of speech. According to Professor Axe, sheep suffer severely from the allied species. BIBLIOGRAPHY (No. 22). Bastian, H. C., " On the Anatomy of the Nematoids," ' Phil. Trans./ 1866, p. 54,5.Bellingham, 0. B., " On the frequency of Trichocephalus dispar in the Human Intestines/' ' Rep. of Brit. Assoc., in Dubl. Journ./ 1838, and in ' Med. Chir. Revi/ 1838; see also Bibliog. No. 33 (and the biography of Bellingham by Dr Mapother, in ' Dubl. Jrn. Med. Sci./ 1877, p. 471). Busk, G., " Anat. of T. dispar;' 'Ann. Nat. Hist./ vol. vii, 1841. Chioje, sul Tricocephalo disparo, &c., 1836.- Colloid, ' Entozoa/ pp. 69 and 329. Idem, ' Worms/ pp. 31 and 67. Davaine, 1. c., p. 205. Idem, ' Compt. Rend./ 1858, p. 1217, and 'Journ. de Physiol./ 1859, p. 296. Dubini, ' Entozoografia umana/ p. 83. Dujardin,}. c., p. 32. Eberth, " Die Generationsorgane von T. dispar," f Sieb. und Koll. Zeitschr./ 1860, s. 384. Gibson, D., " On a Case of Paralysis, with loss of speech, from intestinal irrita- tion (produced by T. dispar), ' Lancet/ Aug. 9th, 1862, p. 139. Goeze, ' Naturg./ s. 112. Gurlt, 'Path. Anat./ p. 350. Kuchenmeister, 1. c., s. 235 ; Eng. edit., p. 321. Leidy, ' Proc. j^.cad. Phil.,' viii, p. 53.-*-Leuckart, 1. c., s. 465. Mayer, Sieb. und Koll. ' Zeitsch. f. wiss. Zool./ Bd. ix, s. 367 ; Bd. x, s. 233, and s. 383, 18S8-60. Herat, 'Diet. Sc. Med./ p. 560. Von Siebold, 'Wiegm. Arch./ 1845. Wilson, E., 'The Veterinary Record and Trans.,' vol. ii, p. 47, 1846. Filaria Bancrofti, Cobbold. The history of the discovery of this entozoon is second only in interest to that of Trlchnm spiralis. Step by step the facts have been evolved by a slow process of observation, and from the data thus afforded a toler- ably connected narrative of the probable life-cycle of this NEMATODA 181 entozoon may now be offered. To place matters beyond all doubt much remains to be done ; yet that which has been accomplished is, or ought to be, of surpassing interest alike to the physician, the scientific pathologist, the epidemiologist, and the philo- sophic naturalist. In the case of Trichina, Owen's nomencla- ture was most properly allowed to stand; but for reasons stated below I have not hesitated to employ for this worm, in its adult state, a name differing from that originally given to the hsematozoon which turns out to be its representative larval state. Although the male parasite is at present unknown, the following characters will in the meantime suffice for a diagnosis of the species : Body capillary, smooth, uniform in thickness. Head with a simple circular mouth, destitute of papillae. Neck narrow, about one third of the width of the body. Tail of female simple, bluntly pointed ; reproductive outlet close to the head ; anus immediately above the tip of the tail. Length of largest females, 3| in. ; breadth, ^/' ; embryos, ~ " to T ^ 3 // in length, by ^y to ^" in breadth ; eggs, averaging ^' by ^' from pole to pole. The first discovery of this entozoon, in its embryo state, was made by Wucherer on the 4th of August, 1866. To use Dr Da Silva Lima's words : " At the moment when Wucherer was seeking for the Bilharzia htematobia, he found instead of it an unknown worm. Our illustrious collaborator/' adds Dr Lima, "has made his important discovery known under the modest title of ' Preliminary Notice on a species of Worm at present not described / and still more modestly Wucherer for- mulated in the following manner his judicious and prudent conclusions : It would be rash on my part to put forth a con- jecture on the coexistence of these worms of the haematochy- luria, and on the etiological signification which they might have. I shall therefore abstain until I have been able to make more ample investigations, and until I have been permitted to examine the corpse of a hsematuric, which has not yet been possible." (' Gazeta Medica da Bahia/ Dec., 1868, p. 99.) In the year 1868 Dr J. H. Salisbury referred certain ova which he found in the urine to a new and distinct species of nematode. Although he had no acquaintance with the adult parasite, Dr Salisbury at once placed the " species " in the genus Trichina. Here is what he says : " Trichina cystica (Salisbury). This is a small species which I have found in the 182 PARASITES OF MAN human bladder. In all my examinations I have met with this little entozoon in three cases only. In two of these it was only occasionally met with in the urine. In the other it occurred in great numbers. Frequently from ten to fifteen ova were found in a single drop of urine." It is important to remark, that there was no haematuria in the last-named case, which Dr Salisbury describes as one of " cystinic rheumatism/' or " severe cystinaemia associated with rheumatism and paralysis." The patient " had been insane for several years. Her urine was passed milky, with granular cystine, and was dense and scanty." It is likewise added : "No examination was made of the muscles after death to determine whether this species burrowed in the tissue, like the (Trichina) spiralis" So much for the principal facts recorded by Dr Salisbury. His paper is accompanied by two woodcut figures of the ova (X 300 diam.), and one representation of the embryo (X 1000 diam.). If these figures give the size correctly, the ova mea- sure only about 5^," in length, by-^" in breadth, whilst the embryo would be about 3^" from head to tail. On the 17th of May, 1872, I communicated to the Metro- politan Counties Branch of the British Medical Association a paper on f Bilhwrzia/ and in an Appendix to it I wrote as follows : " A most interesting circumstance connected with this case of ' Bilharzia' from Natal lies in the fact that I obtained from the patient some other urinary parasites in the egg-condition (fig. 38). On five separate occasions I obtained one or more specimens of the eggs or embryos of a minute nematode. In one instance there were about fifty of these ova in the urine, their contained embryos being well developed and in a state of activity. Usually they were all in this advanced condition ; but on the 25th of July, 1870, several were observed in much earlier stages of development. One of these was of a triangular form ; its shape, granular contents, and clearly defined limiting membrane, indicating separation from the rachis within the ovarian tube. Another early form was per- fectly spherical, with a well marked chorional envelope and double contour. These forms measured about -~^ f in diameter. The fully grown eggs observed at the same time gave a longitudinal measurement of ^ 5 by y^" in breadth. On adding any stimulus, such as diluted sulphuric acid, the embryos moved themselves freely within the egg. After allowing the NEMATODA 183 urine to stand for forty-eight hours, I found, on the 27th of July, that the shells of the ripe ova had dissolved, leaving the embryos dead, but still coiled within a fine transparent en- velope. In this state they were easily separated and examined, when they gave a measurement of " in length, by $" in breadth. On two occasions, whilst engaged in rearing the larvae of Bil- harzia in water, I noticed single speci- mens of these embryos lying dead; and one of the examples thus ob- FlG 38 _ Group of effgs and served gave a length of J/, by ^ 5 " in S^^T^^*' breadth." Knowing what errors of interpretation have often crept into helminthological literature I was more than usually cautious in pronouncing upon the source of these urinary parasites. Ac- cordingly, I remarked that " future discoveries might enable us to identify the species of nematode to which these ova are referable." I also added : " Notwithstanding discrepancies as to size, I am inclined to think that Dr Salisbury and myself have been made acquainted with nematode eggs and embryos referable to one and the same species of parasite. I do not care to speculate as to the origin of these ova. Long ago I gave in my adhesion to the determinations of Schneider in respect of the so-called Spiroptera hominis, but I am by no means certain that his position may not be disturbed by fresh discoveries. It is not a little remarkable that the parents of my patient should have averred that she passed three small vermiform entozoa by the urethra, corresponding, to judge from their verbal statements, very closely with the ordinary appearances of Filaria piscium." Having written thus much seven years back, it is with natural pleasure that I find my anticipations already verified. Knowing that I was dealing with parasites in their earliest larval stages, it never occurred to me to give a specific name to them, and I could not possibly approve of Dr Salisbury's nomenclature, for which there was no good ground. In the original discovery Dr 0. Wucherer procured the worms from the chylous urine of a female in the Misericordia Hospital at Bahia ; and on the 9th of the following October, 1866, he obtained similar worms from another female suffering from 184 PARASITES OF MAN hgematuria. He also afterwards found them in a man whose urine was slightly chylous, but not haematic. In all cases these sexually -immature nematodes were alive. In September, 1872, Dr A. Corre furnished a careful description of similar worms found by Dr Crevaux in a haemato-chylurous patient at Guade- loupe. Dr Crevaux frequently examined the blood of this patient but found no haematozoa. In like manner in Brazil, Dr J. Silva Lima sought in vain for worms in the blood of no less than five patients, all of whom suffered from haematuria, and whose urine contained numerous nematoid worms. Towards the close of the year 1872 the biological world was startled by the announcement of the discovery of minute Filariaa in human blood. Dr T. R. Lewis had found microscopic worms in the blood, and also in the urine, of persons suffering from chyluria. The worms could be obtained from day to day by simply pricking any portion of the body with a finely pointed needle. To this haematozoon Lewis gave the trinomial term Filaria sanguinis hominis, which thus fitly distinguished it from the Filaria papillosa hamatica canis domestici described by Grube and Delafond. Dr Lewis found the average size of the parasite to be y^" in length by 53^5" in breadth. He observed that while it exists in the blood the body is enclosed in a delicate transparent tunic or cyst. The worm was never absent from urine in chyluria. In a case in which there was a milky discharge from the eyes the worms were also detected. In one case Lewis calculated that 140,000 Filarias were present in the blood a number certainly not relatively large seeing that MM. Grube and Delafond estimated the verminiferous blood of their several dogs to contain numbers varying from 11,000 to 224,000. Lewis also found Filarise in the kidneys and supra-renal capsules of a woman who died of chyluria. It did not appear probable that the worms underwent further development in the huinan body. On this point Lewis remarks : " Not only may those haematozoa found in man live for a period of more than three years, but there is no evidence that they have any tendency to develop beyond a certain stage as long as they remain in the circulation." Dr Lewis judged that the form of chyluria associated with this condition of the blood was local and intimately related with a tropical climate. The milky condition of the urine comes on suddenly, not only at first, but on succeeding occasions also. It is frequently accompanied by more or less distinctly marked symptoms of various other NBMATODA 185 obscure diseases, including temporary swellings in the face or extremities. From certain appearances of intestinal ulceration Lewis thought that the parasites might gain access to the system by the alimentary canal, possibly from the tank-water or the fish inhabiting it. He considered the state of the urine to be due to the mechanical interruption offered to the flow of the nutritive fluids of the body. The accidental aggregation of the Hsematozoa might give rise to obstruction of the currents within the various channels, or occasion rupture of their extremely delicate walls, and thus cause the contents of the lacteals, lymphatics, or capillaries, to escape into the most conveniently placed excretory channel. Compressed into a small compass, I think the above is a fair statement of the leading facts and phenomena discovered by Lewis. The whole subject of haamatozoology immediately received additional impulse, the consequences of which have not yet terminated. In this country Welch was stimulated to investigate the structure of Filaria immitis in the dog, whilst others sought diligently for nematoid hgematozoa abroad. On the 20th of April, 1874, Dr Prospero Sonsino communi- cated to the Neapolitan Royal Academy his memoir entitled " Researches concerning Bilharzia hamatobia in relation to the endemic hsematuria of Egypt, with a notice concerning a nema- toid found in the human blood." In this brochure he made known the fact of his having discovered microscopic Filarias in a young Egyptian Jew, in the following words : " On the 1st of February last, having well washed the finger of the boy, I placed one drop of blood under the microscope, when with astonishment I discovered a living organism of the form of a nematode, resembling Anguillula, in the midst of the haematic corpuscles. The worms glided amongst the globules, which were tossed about by their lively movements, showing various appear- ances according as they presented themselves either from the sides, the edges, or the front of the disk" (''Ricerche/ &c., pp. 11, 12). Dr Sonsino took every precaution to prevent error, subse- quently verifying his "" find " from the same patient. Dr Sonsino directs attention to two of his own characteristic figures of the worm, and subsequently states not only that he found examples of the Filariae in the urine of this same youth, but also " in the urine of another patient." The parasites from these two sources being figured side by side, it was clear, from their resemblance, that they referred to one and the same species of entozoon. Dr 186 PARASITES OF MAN Sonsino having compared the facts supplied by these cases, was satisfied that the nematodes in question were specifically identical with those that I had previously obtained from my little African patient. However, Dr Sonsino was of opinion that his Filarise were not precisely the same as those that had been described by Lewis. On the 8th of April, 1876, I received from Dr William Roberts, of Manchester, some capillary tubes, charged with blood, obtained from a patient suffering from chyluria. The tubes had been transmitted by Dr Bancroft, of Brisbane, Queensland, Australia ; and in fulfilment of the donor's request, Dr Roberts afforded me an opportunity of examining their contents, he having himself verified Bancroft's statement that they contained Filariae. It was not until May 22nd that I found opportunity to confirm the observations of Drs Bancroft and Roberts. The contents of some of the tubes had by this time completely dried up ; but in others, to which diluted glycerine had been added, the blood appeared tolerably fresh. In what might be reckoned as the sixth part of the contents of one of the tubes, spread on a glass slide, I detected about twenty Filariae, three of which I sketched in situ, in order to compare them with the figures of Lewis, and also with others that I had procured from my Bilharzia- patient in the year 1870. There could not, I thought, be any doubt as to the identity of all these sexually-immature nematoids. One novelty, however, presented itself in the presence of a solitary and empty egg envelope, measuring about ~ 5 of an inch in its long diameter, and thus corresponding precisely with the ova that I obtained from the urine in my Bilharzia case. According to Bancroft, chyluria is somewhat common in Brisbane ; and the case here brought forward was not the only one of the kind which had already furnished Filariae in the blood. _ The patient was a little girl ten years of age. Thus stood the facts in the spring of 1876. Having informed Dr Bancroft that a nematoid egg had been detected in the Australian blood transmitted to England, he was induced to make further investigations. These happily resulted in the discovery of the adult worm; the circumstances attending the " find" being recorded by Dr Bancroft in a letter written to myself and dated from Brisbane, Queensland, April 20th, 1877. He wrote as follows : " I have labored very hard to find the parental form of the parasite, and am glad to tell you that I NEMATODA 187 have now obtained five specimens of the worm, which are waiting to be forwarded by a trustworthy messenger. " I have on record about twenty cases of this parasitic disease, and believe it will be the solution of chyluria, one form of hgematuria, one form of spontaneous lymphatic abscess, a peculiar soft varix of the groin, a hydrocele containing chylous fluid, together with some forms of varicocele and orchitis. These I have verified. In the colony there are no cases that I can find of elephantine leg, scrotal elephantiasis, or lymph scrotum ; but from the description of these diseases in the volume on skin and other diseases of India by Fox, Farquhar, and Carter, and from Wm. Roberts' article on the latter in his volume on urinary diseases, I am of opinion that the parasitic nature of the same will be established. " The worm is about the thickness of a human hair, and is from three to four inches long. By two loops from the centre of its body it emits the Filariae described by Carter in immense numbers. " My first specimen I got on December 21st, 1876, in a lymphatic abscess of the arm ; this was dead. Four others I obtained alive from a hydrocele of the spermatic cord, having caught them in the eye of a peculiar trochar I use for tapping. These I kept alive for a day and separated them from each other with great difficulty. The worm when immersed in pure water stretches itself out and lies quite passive. In this condi- tion it could be easily washed out of hydroceles through a large-sized trochar from patients known to suffer from Filariae." In July, 1877, I announced Bancroft's discovery in the ( Lancet,' naming the parasite Filaria Bancrofti, and in the following September I sent the editor an account of the results of my study of the adult worms received from Brisbane in the interval. These examinations supplied me with the diagnosis already given (p. 181). On the 29th of September, 1877, Dr Lewis published a paper in the ' Lancet,' wherein, after alluding to my previous announce- ment respecting the discovery of Filaria Bancrofti, he describes under the name of Filaria sanguinis hominis a mature worm, which was evidently the same parasite. Not unnaturally Dr Lewis put aside the nomenclature I had employed, on the ground that the name originally given by himself to the embryonal form ought to be retained, and that " a new name, if not necessary on anatomical grounds, would only lead to confusion." 188 PARASITES OF MAN Personally I have no objection to Lewis's specific name, but if the question of priority is to determine the nomenclature, then I fear we ought to call the species Filaria Salisburyii. Obviously the retention of Dr Salisbury's nomenclature (Trichina cystica) would be unsuitable and misleading. FIG. 39. Filaria Sancrofti. a, Female (iiat. site); b, head and neck (x 55 diara.); c, tail; d, free embryo (x 400 diani.) ; e, egg containing an embryo;/, egg, with mulberry cleavage of the yolk (X 36U diam.). Original. When (prior to Lewis's discovery of the haematozoa) I had myself encountered larval nematodes of the same character as those described by Salisbury, I, like Wucherer, was careful not to employ a special name for an immature form, which might or might not represent a worm hitherto known to science. The paper in which I described the adult worm from specimens NEMATODA 189 supplied by Bancroft appeared in the ' Lancet/ Oct. 6th, 1877, the facts being stated as follows : On the 28th of August, 1877, I received a small collection of entozoa. The box contained the promised Filariae, and also eight bottles filled with various intestinal worms taken from animals. The Filariae were enclosed in four small tubes and preserved in glycerine. Three of the tubes (marked 1, 2, 3) contained sexually-mature worms, the fourth being labelled " Sediment from adult Fil. sang. young and ova." I described their contents in succession. Thus, on the 6th of September, 1877, I examined the Filaria in tube No. 3. The specimen was injured and in four portions, these collectively measuring three inches in length. Although, to the naked eye, the worm had appeared to Dr Bancroft to be of the thickness of an ordinary human hair, yet I found it about ^" at the thickest part. It was a female. At the same time I examined the specimen in tube No. 1. This was also a female. Towards the centre of the body a hernial protrusion of the uterine horns and intestine had taken place. In a lithograph sent by Dr Bancroft this specimen was figured and described as the ' ' parent worm of the Filaria sanguinis, emitting young Filaria from two loops." Later on I examined the contents of tube No. 2. In it I found one tolerably perfect female Filaria, and also a delicate shred forming part of one of the uterine horns of another worm. This filament measured one inch and a half in length, and was coiled round the com- plete worm. On transferring it to a watch-glass containing water, hundreds of embryos made their escape. Owing to the transparency of the tissues I had much difficulty in finding the reproductive outlet, and the effort to find it was all the greater because Bancroft's figure had misled me. At length I found the vagina and its orifice close to the head (about " from it), the anal orifice being placed within the ~" from the extremity of the tail. The vaginal pouch, T J/' long, was crowded with embryos, and a constriction marked its junction with the uterus proper, which appeared to divide lower down at a distance of yL" from the head. Towards the tail a fold of the tuba Fallopii was seen to extend to within i" of the extremity. All sections of the uterine system were crowded with germs, eggs, and embryos in their usual relative situations. My examinations of the ova and embryos were chiefly made from the (( sediment " sent in a special glass tube. The fully formed embryos were jjj" in length by 5" in breadth. They 190 PARASITES OF MAN each showed a double skin, the outer envelope in the more advanced specimens leaving clear spaces at either end of the body, resulting from commencing ecdysis. I saw no trace of intestinal tube, but a central line of condensation marked an early differentiation of the somatic granular contents. The less advanced embryos were mostly enclosed in a chorional envelope, the smallest free embryos measuring only ~" in length by ^" in breadth. These had no double contour. The ova, whose yolk- contents were still in various stages of cleavage, gave an average long diameter of g~ to ^5 of an inch. Such are the facts I made out, and they enabled me to amend the characters of the species. As regards nomenclature, I associated Dr Bancroft's name with the sexually- mature worm as being in harmony with the binomial method and little calculated to mislead ; moreover, it helped to fix both the source and date of the discovery (Bris- bane, Dec. 21st, 1876). The use of this nomenclature detracts nothing from the high merits of Lewis, who first named the immature worm Filaria sanguinis hominis. As it now turns out, both Dr Salisbury and myself had previously been made acquainted with the young of Filaria Bancrofti ; but it was reserved for Lewis to discover the haematozoal character of the embryos of this worm, and actually to take them from the blood. It was a singular circumstance, that when I was engaged in treating my little African patient for trematode haematozoa, it never once occurred to me that the numerous nematoid embryos mixed with the Bilharzia ova were haema- tozoal. As before remarked, it was alleged that my patient had passed worms two or three inches long by the urethra. I therefore concluded that these were the parents of the eggs and embryos, and that all of them were urinary. The infer- ence was wrong, but it has instructively shown how near one may go towards a great discovery without really making it. As regards the larvae, notwithstanding some slight differences in regard to size and so forth, I have little hesitation in saying that all the embryo forms severally described by Salisbury, by myself, by Lewis, Sonsino, Wucherer, Crevaux and Corre, Silva Lima, Bancroft, Hanson, and others, are referable to one and the same species. Into the clinical bearings of this subject it is impossible for me to enter at any length, but I may remark that these para- sites appear to be associated with, if not actually the cause of, NEMATODA 191 several distinct morbid conditions. To one of these Bancroft has given a separate name (Helminthoma elastica). This is a highly elastic form of growth to which I have already alluded under the title of " lymphatic abscess of the arm." In the first valuable report on Haematozoa, by Dr Patrick Manson, of Amoy, China, this careful observer gives interesting particulars of no less than fifteen cases in which hsematozoa were found. Two of these patients had Elephantiasis scroti, two had lymph- scrotum, two were lepers (one having scrotal disease), two had enlarged inguinal glands, one had anasarca; and of the remain- ing six, spoken of as having no concomitant disease, one had enlarged glands and abscesses, and another suffered from marked debility. It would thus appear that what is ordi- narily termed " good health " is rarely associated with a haema- tozoal condition of the blood in the human subject. The cases given by Lewis and Manson, where absolutely no recog- nisable disease existed, must be regarded as exceptional. Dis- ease, moreover, may exist without any palpable symptoms being exhibited by the f( bearer," and thus perhaps it was with the hsematozoal dogs of Gruby and Delafond to which I shall again have occasion to allude. Even those animals that carried upwards of two hundred thousand microscopic Filarise in their blood appeared to suffer no inconvenience whatever. In the autumn of 1877 Dr Da Silva Lima published an article in the ' Grazeta Medica da Bahia/ in which he dwelt upon the labors and merits of Wucherer, and, judging from an omission in one of my memoirs, he supposed that I had insuffi- ciently acknowledged Wucherer's claims. A translation of this article appeared in the ' Archives de Medicine Navale/ with an important appendix by Dr le Eoy de Mericourt. In this addendum the French savant showed that the omission on my part was unintentional, and had been corrected by me in a later memoir. Not only had I been amongst the earliest in England to enforce Wucherer's claims in respect of the micro- Filarise, but I had first announced his discoveries in connection with Anchylostoma duodenale. In my translation of Wucherer's memoir (' Ueber die Anchylostomum Krankheit ') I spoke of the melancholy satisfaction I had in knowing that the memoir in question was " among the last that appeared from the pen of that gifted and amiable physician." Some notice of Dr Lima's paper and its appendix by Dr A. le Eoy de Mericourt appeared in the ' Lancet ' for Jan. 5th, 1878, and I also published a full 192 PARASITES OF MAN traoslation of it, with explanatory notes, in the ' Veterinarian ' for Feb., 1878. Later on, in the 'Lancet' (March 23rd, 1878), Dr Da Silva Lima published an interesting letter correcting a misconception that had incidentally arisen in the mind of a commentator (on the Helminthological work of 1877), and at the same time he pointed to the original facts connected with the discovery of Wucherer's Filaria. As my views are in perfect accord with those of Dr Da Silva Lima, I can only regret that errors of interpretation should have crept into the discussion, Dr Lima honorably recognises the nomenclature (Filaria Ban- crofti) which I proposed for the adult worm, and only claims for Wucherer that which is fairly due. On the 4th of January, 1878, I received from Dr Patrick Manson a manuscript in which he announced the discovery of the Iarvs9 of Filaria sanguinis hominis in the stomach of mosquitoes. Already, in April, 1877, Dr Bancroft had in- formed me of his expectation of finding that these insects sucked up the larvae of the Filaria whilst engaged in their attacks on man. Dr Bancroft's supposition was a very natural one, but it remained for Manson to make the actual discovery of the existence of human hsematozoa, or parasites that had been such, within the stomach of Culex mosquito. I lost no time in making the principal facts public (' Lancet,' Jan. 12th, 1878). Dr Manson at the same time forwarded for publication a record of thirty-five additional cases of haematozoa occurring in Chinese subjects, together with additional particulars of one of the cases already published in the c Customs Gazette.' These were afterwards published as separate contributions in the ' Medical Times and Gazette.' Dr Manson likewise for- warded materials for a paper entitled " Further Observations on Filaria sanguinis hominis." In this communication he gave an analysis of the cases (sixty-two in all) in which he had observed the haematpzoa, and he added valuable statistical evidence as to the prevalence of Filariae in the Amoy district, dwelling especially on the influence of age, sex, and occupation in determining the presence of the parasite. He also described the morbid states with which these entozoa were commonly associated. On the 7th of March, 1878, I formally communicated to the Linnean Society a detailed account of Hanson's investigations relating to the metamorphoses undergone by the Filariae within the body of the mosquito. In this paper Manson pointed out NEMATODA 193 that the female mosquito, after gorging itself with human blood, repairs to stagnant water for the purpose of digesting the blood, and also for the purpose of depositing its eggs. During this period, which lasts four or five days, the Filariae undergo remarkable changes. Subsequently, in a more perfect state, they escape into the water, and in this advanced stage they are conveyed to the human body along with the water as drink. Dr Manson persuaded a Chinese, whose blood was previously ascertained to abound with Filarise, to sleep in a " mosquito house. " In the morning the gorged insects were captured and examined under the microscope. A drop of blood from the mosquito was found to contain 120 Filariae, but a drop taken from the man's hand yielded only some thirty specimens. Further stages of development are accomplished within the human host, ending in the sexual maturity of the parasite. After fecundation successive swarms of embryos are discharged by the female worm, a part of whose progeny eventually gains access to the blood. Before I proceed to summarise the whole body of facts I must in the next place state that Manson and myself con- tributed a joint communication to the Medical Society of London on the 25th of March, 1878. In this memoir I especially dealt with the question of priority in connection with the dis- covery of the adult worm. I then restated that the adult parasite was discovered by Dr Bancroft on December 21st, 1876. The discovery was verified by Dr Lewis on August 7th, 1877, by Dr Silva Araujo October 16th, 1877, and by Dr F. dos Santos November 12th, 1877. I gave these dates unhesi- tatingly, without, however, in any way prejudicing the question already raised in respect of the identity of the worms found in each case. My own mind was fully made up on that point, and affirmatively so. Dr dos Santos' find was made in conjunc- tion with Dr J. de Moura in a case of lymphatic abscess of the" arm. Clinically viewed, the case published by Dr Araujo must be regarded as unique. Not only were adult and embryonic Filariae found in the same patient, but, what was far more sur- prising and interesting, the patient displayed in his own person several of the disorders hitherto found apart ; and he was more than once attacked by one or two of the diseases. He expe- rienced a first attack of chyluria three years ago, then attacks of craw- craw commencing a year ago, the latter being attri- buted to bathing in a particular lagoon. He had a second 13 194 PARASITES OF MAN attack of chyluria six months back, at which time lymph- scrotum appeared, and also scrotal elephantiasis. Dr Bourel- Ronciere pronounced this case to be unique, and attributed nearly all the disorders to the presence of Wucherer's em- bryonic FilariaB. In a very elaborate analysis of and com- mentary on Dr da Silva Lima's second memoir, Dr Bourel- Ronciere warmly claims for Wucherer the supreme honor in all these discoveries. A number of affections hitherto regarded as distinct, and all of which appear to be due to the action of Filarise, are regarded by Dr Bourel-Ronciere as mere phases of one and the same disorder. This affection he terms Wucherer' s helminthiasis. Dr Manson had indeed arrived independently at a similar conclusion, and I am confident that Wucherer, were he alive, would in this particular aspect of the question be the last to claim priority either to Lewis, to Bancroft, or to Manson. In this place I may observe that Dr Pedro S. de Magalhaes, of Rio de Janeiro, detected free microscopic nematodes in the potable waters of Rio (agua da Carioca), which from their similarity he supposes may have some genetic relation with Filaria Bancrofti. In this opinion I cannot share. As regards the metamorphoses of the embryo, Manson states that for a little while after gaining access to the stomach of the mosquito the embryo undergoes no change (Fig. 40, a). In a very few hours changes commence, resulting in wider separation of the outer skin and an appearance of transverse markings on the body within (b). In the next stage oral movements occur; the striation becomes more marked, and the outer envelope is cast off (c). Then the striated lines disappear and a dotted appearance is substituted (d). From this condition the embryo passes to what Manson calls the chrysalis stage, in which nearly all movement is suspended and the large spots gradually dis- appear (e, f, g, h, i, j y fc) . The tail continues to be flexed and extended at intervals and the oral motions cease. By the close of the third day the embryo becomes much shorter and broader; but the finely pointed tail retains its original dimen- sions, projecting abruptly from the sausage-shaped body (w, n). Large cells next appear in the interior of the body, and by a little pressure one may detect indications of a mouth (o, p, q, r) . At this period the embryo begins to elongate, and at the same time to diminish in width ; but the growth takes place chiefly at the oral end of the body. The mouth becomes four-lipped, NEMATODA 195 FJG. 40. Larval Filarise in various stage of growth from the mosquito ; a to d, repre- senting the first stage of metamorphosis during the first 36 hours; e to o, the changes occurring during the second stage, to the close of the third day; p to t, forms seen during the third stasje of metamorphosis from the fourth day onwards. The figs, u, v, represent the head and tail only, whilst t shows the young Filaria in an advauced stage, and drawn to a much smaller scale, than the others which are here magnified about 125 diameters. Much reduced from Mansou's original figures. 196 PAEASITES OF MAN open, and funnel-shaped, and from it a delicate line can be distinctly traced passing to an opening near the caudal extre- mity, the tail itself gradually disappearing (s, t). Speaking of the most advanced stage Manson says : ' ' A vessel of some sort is seen in the centre running nearly the whole length of the body and opening close to one extremity. This end is slightly tapered down and is crowned with three or perhaps four papillae, but whether this is the head or tail, and whether the vessel opening near it is the alimentary canal or the vagina, I cannot say/' Now it is quite evident, I think, from Hanson's figures that he has here faithfully represented the head and tail, the former (u) to the left, the latter (v) to the right. In his manuscript (from which I am now quoting) there is no special reference to these two figures ; but it is easy to see that these terminal sections of the body of the advanced embryo closely correspond with the head and tail of the adult worm (Filaria Bancrofti). The curved line passing to the left (u) evidently indicates the commencement of the partially-formed vagina. How completely Manson took the initiative in this part of the work is evident even from Lewis's own later observations. In a paper published in March, 1878, Dr Lewis, writing from Calcutta and speaking of the role of the mosquitoes, says : " I had repeatedly examined, in a cursory fashion, these and other suctorial insects, but had not observed any parasites suggestive of these einbryo-haematozoa, hence, when, on receipt of a com- munication from Dr Manson a couple of months ago, a renewed search was made, I was surprised to find that four out of eight mosquitoes, captured at random in one of the servants' houses, harboured specimens of haematozoa to all appearances identical with those found in man in this country. After this, however, several days elapsed before any mosquitoes could be obtained which contained these embryo-nematoids, and the specimens obtained on the next occasion were devoid of the enveloping sheath, which appears to characterise the kind found in man out here, and apparently, according to Dr Manson, in China also." Further on Lewis also remarks, " When the insect is caught shortly after feeding and the contents of its stomach examined microscopically, the haematozoa, if present, will be observed to manifest very active movements, which may pos-' sibly continue for several hours on the slide. If the insect be kept for twenty-four hours before examination it is probable NEMATODA 197 that the movements of the parasites will be more sluggish, and their form probably altered owing to irregular contractions and dilatations of their substance changes which may also occasion- ally be observed when embryo-haematozoa are preserved on a glass slide, and they may sometimes be kept alive thus, if in suitable media, for two or three days. When the insect is not examined till the third day, the contained parasites will pro- bably manifest marked signs of disintegration and possibly every indication of life will have disappeared from many of the specimens. After the third or fourth day I have not seen any active specimens of these entozoa in the stomach or in any part of the alimentary canal of the mosquito ; those which remain have undergone more or less fatty degeneration, and are readily stained with eosin, which, as far as my experience goes, is not the case so long as they are alive and active. After the fourth or fifth day it is very rare that traces of any haeinatozoa-like objects can be detected at all, so that it must be inferred either that they have succumbed to the digestive action of the insect's stomach or been disposed of along with the excreta." An important addendum by Lewis records a fortunate incident as follows : " It was observed that nearly all the mosquitoes captured in one of the servants' houses contained haematozoa, so that the supply of suitable insects in all the stages of their growth became amply sufficient for all requirements. The result of the examinations under these favorable conditions has shown that although the stomach digests a great number of the ingested haematozoa, as mentioned above, nevertheless others actually perforate the walls of the insect's stomach, pass out, and then undergo developmental stages in its thoracic and abdominal tissues." I may here observe that Sonsino has instituted a comparison between the embryos of this Filaria and those of Anchylostoma, by which it appears that the former measure 0'218 to 0*330 mm. in length, and those of Anchylostoma 0*430 mm. The haema- tozoa are about forty times longer than broad, and the larval anchylostomes only fourteen times longer. The tail of Filaria is conspicuously longer. In the ' Lancet ' for June 22nd, 1878, an announcement appeared from the pen of Mr D. H. Gabb, of Hastings, stating that a patient under his care formed the habitat of Filaria sanguinis hominis ; and in the autumn of the same year a paper which I read to the Linnean Society in the spring 198 PARASITES OP MAN was published. In that paper the following summary was offered : 1. Filaria Bancrofti is the sexually- mature state of certain microscopic worms hitherto obtained either directly or indirectly from human blood. 2. The minute haematozoa in question hitherto described as Wucherer's Filariae, Filaria sanguinis hominis, Trichina cystica, Filariose dermathemaca, and so forth are frequently associated with the presence of certain more or less well-marked diseases of warm climates. 3. The diseases .referred to include chyluria, intertropical endemic hsematuria, varix, elephantiasis, lymph scrotum, and lymphoid affections generally, a growth called helminthoma elastica, a cutaneous disorder called craw-craw, and also leprosy. 4. It is extremely probable that a large proportion, or at least that certain varieties of these affections are due to morbid changes exclusively resulting from the presence of Filaria Bancrofti or its progeny within the human body. 5. It is certain that the microscopic haematozoa may be readily transferred to the stomach of blood- sucking insects, and it has been further demonstrated that the digestive organs of the mosquito form a suitable territory for the further growth and metamorphosis of the larval Filariae. 6. The character of the changes undergone by the micro- scopic Filariae, and the ultimate form assumed by the larvae whilst still within the body of the intermediate host (Culex mosquito), are amply sufficient to establish the genetic relation- ship as between the embryonal Filaria sanguinis hominis, the stomachal Filariae of the mosquito, and the sexually-mature Filaria Bancrofti. In the month of September, 1878, I received a letter from Dr da Silva Lima announcing the fact that Dr Araujo had verified the existence of the embryos of Filaria Bancrofti in mosquitoes, at Bahia. These mosquitoes had, I understood, attacked a French priest in whose blood Dr Araujo also detected Filariae. Thus, it fell to the lot of Araujo, through his untiring zeal, to verify in Brazil all the separate discoveries of Bancroft, Manson, and Lewis. In the October issue of the f Pathological Society's Transac- tions ' for 1878 Dr Bancroft records numerous cases of filarious disease, and he gives a succinct account of the circumstances connected with his original discovery. NEMATODA 199 In a clinical lecture published October 12th, 1878, Dr Tilbury Fox seeks to diminish the value of these discoveries, characterising helminthological investigators as merely " recent writers/' Dr Fox denies that Filariae are a cause of true elephantiasis, but admits the occurrence of ff elephantoid in- flammation and inflammations due to Filariae." Dr Fox's state- ment that " Filariae have not been found in uncomplicated elephantiasis, that is, in disease without chylous exudation," seems to me to be directly at variance with Hanson's recorded experiences. I hold that Manson has confirmed the truth of Lewis's views, and that he has thoroughly proved that (to use his own words) " varicose groin glands, lymph scrotum, elephantiasis, and chyluria are pathologically the same disease." In the first instance I was myself led to conclude that some of the forms of elephantiasis might be due to other causes than obstruction of the lymphatics caused by the presence of Filariae ; but the explanations of Lewis, of Bancroft, and of Manson more especially, have almost entirely removed this doubt. Those who seek to explain away the connection between genuine elephantiasis and Filariae will do well to study Hanson's last important memoir. He shows that " elephantiasis and allied diseases are much more frequently associated with the parasite than are other morbid conditions." This fact is brought out very clearly in his table of 670 cases, from which it appears that 58 per cent, of cases of Filaria are associated with elephantoid disease. When this opposition to Hanson's views is likely to cease (on the part of those who do not happen to have been in any way instrumental to the discoveries in question) it is not easy to say. In a brief communication which appeared in the last number of the 'Hedical Times and Gazette' for 1878, Dr Hanson successfully combats the doubts that have been enter- tained respecting the role of the mosquito. Because Lewis found that canine haematozoa were digested, and thus perished in the stomach of mosquitoes, it had been argued that human haamatozoa must necessarily undergo similar processes, and consequently die. Those who oppose the views of helmintholo- gists in respect of the intermediary host-function of insects on such grounds can have very little general, and still less special knowledge of the phenomena of parasitism. It is the old story. When any new discovery is made, it must always pass through the ordeals of denial and doubt before it can be gene- 200 PARASITES OF MAN rally accepted as true ; and, as in the case of Jenner's immortal discovery, there will always remain a certain number of peculiar people who show themselves hostile to every advance in science. Dr Manson may take comfort from this consideration, and rest assured that the value of his discovery is quite unaffected by the opposition referred to. Since I communicated the results obtained by Manson, Lewis, myself, and others to the Linnean Society, an even more exhaustive summary of the facts has been published by Dr Bourel-Ronciere, in the ' Archives de Medecine Navale/ The distinguished author does full justice to the writings of English helminthologists, and dwells, with emphasis, upon the finds and interpretations of Lewis, Manson, and Bancroft. Incidentally, also, he comments upon Sir Joseph Fayrer's early recognition of the etiological identity of haemato-chyluria and elephantiasis, on other than helminthic grounds. The frequent concurrence of the two affections had especially struck Sir J. Fayrer as pointing to a probable common origin. He had also surmised that the disorders might be due to parasites. Dr Bourel-E-onciere, alike with the caution, precision, and logical reasoning of a cultured savant, concludes his elabo- rate review in the following terms : " There are the facts. Certainly, many points remain obscure, many problems await a solution, and the last word has not been said on the actual part which the parasite plays in the pathogenesis of the affections above enumerated its mode of action, the importance of its role, the extent of its pathological domain, the habitat of its progenitors, their identity, and so forth. All these questions will only be elucidated by necroscopic researches, which at present remain absolutely wanting." " However, notwithstanding the doubts which hover over the future value of these curious discoveries, it is difficult not to recognise their importance in' the study of certain tropical diseases which up to the present time have been attributed to vague and undetermined causes haemato-chyluria and ele- phantoid affections principally. Apart from the interest which attaches to the natural history of the nematoids, they raise, in effect, etiological and prophylactic questions, the extreme im- portance of which we believe it would be needless to demon- strate. It is greatly to be desired that the researches should be taken up in other parts of the globe, where endemicity and perhaps greater facilities for necroscopic investigation would NEMATODA 201 render them fruitful Cochin-China, Tahiti, &c. Fresh ob- servations are necessary to confirm the first and to fill up notable gaps. The way has been brilliantly opened by the English and Brazilian physicians. Let our colleagues in the French colonies put their shoulders to the wheel ; they have before them a vast field of study to explore." Since the above remarks were written I have received several communications from Dr Bancroft, and also others from Drs da Silva Lima, Araujo, Assis Sousa, Paterson, Hall, of Bahia the two last named being English physicians in practice there. I regret that I can do little more than refer to the writings of these authors in the Bibliography below ; but I may observe that Drs Paterson and Hall have ascertained that the proportion of the population of Bahia affected by Filaria is 8~ per cent. Out of 309 persons examined, 26 had haematozoa, which is, roughly, one in twelve, or more strictly, 8*666 per cent. Amongst recent memoirs that by Sir J. Fayrer, read to the Epidemiological Society on the 5th of February, 1879, deserves especial attention. In regard to its significance, I have only space to remark that, much as we may regret the little interest shown by our hospital physicians and surgeons in this subject, it is particularly gratifying to see experienced Indian officers like Sir J. Fayrer, Mr Macnamara, and Dr John Murray, com- ing forward both to aid and render homage to their junior colleagues in Eastern parts, who are successfully labouring to advance the cause of helminthology and scientific medicine. In concluding this subject I may observe, that one of the greatest hindrances to the due recognition of the remarkable part played by parasites in the production of human endemics and animal epizootics arises from the circumstance that no incon- siderable number of minute worms may infest a host without obvious injury. This immunity proves nothing. If, for example, we take the case of Trichina we find that several millions of entozoa may exist in the human, or, at all events, in the animal bearer, without producing any symptom of discomfort. In such cases it is not possible to determine the strict limits of health and disease ; nevertheless, were we to double the amount of infection, the imaginary line of demarcation is at once bridged over and the parasites become acknowledged as directly responsible for grave symptoms which may even prove fatal to the bearer. Again, the relative strength and size of the infected host constitute factors that materially limit the power of the 202 PARASITES OF MAN parasite for injury. Where the entozoa are of minute size, and where their injurious action is primarily due to the mechanical obstructions they set up, it is clear that the virulence of the helminthiases, or resulting diseased conditions, will mainly depend upon the number of intruders. Another consideration of the highest value in relation to epidemiology generally, and more especially in regard to the practical question as to the best methods of stamping out para- sitic plagues, is that which refers to the life-history of the entozoon itself. It must be obvious that in all cases where the intermediate host can be captured and destroyed, the life-cycle of the parasite can be broken and interrupted, and if thus broken, there is an end to the further propagation of the species. The knowledge that we have acquired by experi- mental research in this connection has already enabled us to set a limit upon the prevalence of certain well-known disorders, such as Trichinosis, Cestode-tuberculosis, and so forth. In the case of epizootics, however, which are indirectly due to the action of intermediary hosts that cannot be readily captured or destroyed, then our power of arresting the disease is com- paratively limited. In the present case it is probably not necessary either that a dead or living mosquito should be swallowed to insure infection ; but it is necessary that the parasitic larvae should have dwelt within the mosquito in order to arrive at the highest stage of larval growth prior to their re-entrance within the human territory. Undoubtedly, the larvae are swallowed with potable waters. Perfect filtra- tion before use would certainly check, if in course of time it did not totally extinguish several of the many virulent diseases that now afflict the inhabitants of warm climates. It is with reluctance that I terminate this article, but in the closing pages of this work (Book II, Section V) I hope to add a few more particulars in reference to Lewis's latest researches. BIBLIOGRAPHY (No. 23). Araitjo, A. J. P. da Silva, "Me- moria sobre a Filariose," &c., Bahia, 1875 ; see also ' Arch, de Med. Nav./ 1875 and 1878. Bancroft, J., "Cases of Filarious Disease/' in 'Pathological Soc. Trans/ for 1878, vol. xxix, p. 407. BOUT el- Bonder e, "Resume of and Commentary upon the writings of Silva Lima, Silva Araujo, and others," in ' Arch, de Med. Nav.' for March, 1878. Idem, " Pathologie exotique. De Phematozoaire neinatoide de Fhoinme et de son NEMATODA 203 importance pathogenique, d'apres les travaux Anglais et Breziliens des dernieres annees ;" ibid.; for August and Sept., p. 113-134 and p. 192-214, 1878. Oobbold, T. 8., "Discovery of the Adult Representative of Microscopic Filariae," f Lancet/ July, 1877, p. 70. Idem, ' On Filaria Bancrofti,' ibid. Oct., 1877, p. 495. Idem, " Verification of Hasmatozoal Discoveries in Australia and Egypt," ' Brit. Med. Journ./ June, 1876. Idem, " Obs. on Haematozoa," ' Veterinarian/ October, 1873. Idem, " Remarks on the Ova of another Urinary Parasite (in the paper on 'Bilharzia') from Natal/' ' Brit. Med. Journ./ July 27th, 1872, p. 89 ; see also Bibl. No. 12. Idem, " Entozoa in Relation to the Public Health " (various papers), ' Med. Times and Gaz./ Jan. and Feb., 1871. Idem, < Worms > (1. c, p. 151), 1872. Idem, " Hsematozoa ; Fresh Discoveries by Lewis," ' Lancet ' for Feb. 6, 1875. Idem (brief notice), the ' Veterinarian/ p. 209, March, 1875. Idem, " On the Discovery of the Inter- mediary Host of Filaria sanguinis hominis," ' Lancet/ Jan. 12, 1878, p. 69. Idem, " On the question of Priority of Discovery," Rep. of Med. Soc. of Lond., in ' Lancet/ March 30, 1878, p. 465. Idem, ' Mosquitoes and Filariae ' (explanatory note), in 'Brit. Med. Journ./ March 16, 1878, p. 366. Idem, "On the Life-history of Filaria Bancrofti, as explained by the discoveries of Wucherer, Lewis, Bancroft, Manson, Sonsino, myself, and others," " Report of the Proceed, of the Linnean Soc." for March 7, 1878, in 'Pop. Science Rev./ April, 1878; and afterwards published in extenso in ' Journal Linn. Soc./ Oct. 31, 1878. Idem, " On Filaria Bancrofti," in Part iv of a series of papers on the Parasites of Man, in the 'Midland Naturalist/ August, 1878. Idem, "On Filaria sanguinis hominis," in a letter to the 'Lancet/ July 13, 1878, p. 64. Idem, "Filaria) and Leprosy" (case from Bancroft) ; 'Lancet,' Feb. 1, 1879. Corre, A., " Note sur Thelminthe rencontre dans les urines hemato-chyleuses," 'Rev. des Sci. Nat./ 1872. Cosse, "Sur 1'helminthe rencontre par Wucherer et Crevaux," &c., ' Rev. Montpellier/ torn, i, p. 190. Couto, A., "These de concourso," Bahia, 1872. Crevaux, J., ' De Fhematurie chyleuse, &c.," 1872; also in L'Union Medicale/ 1872 (abs. in 'Brit. Med. Journ./ July, 1872, p. 100); also in 'Arch, de Med. Nav./ 1874; and in 'Journ. de FAnat. et de la Physiol./ 1875 (see also Silva Lima). Davaine, C., ' Traite/ 2nd edit., p. 944; ' Haematozoaires/ supp., 1877. Fayrer, Sir J., " Filaria sang, horn.," ' Lancet/ March 16, 1878, p. 376. Idem, " Elephan- 204 PARASITES OF MAN tiasis Arabum," ' Med. Times and Gaz./ Dec. 1, 1877, p. 588; " On the Relation of Filaria sanguinis hominis to the Endemic Diseases of India," in the 'Lancet/ Feb. 8 and 15, and re- printed from the 'Med. Times and' Gazette' (same date), 1879. Oabb, D. H., letter in ' Lancet/ June 22, 1878LeucJcart, 1. c., s. 638, 1876. Lewis, T. K., "On a Haematozoon in Human Blood," 'San. Comm. 8th Rep./ Calcutta, 1872 ; 'Med. Press/ 1873, p. 234; 'Indian Ann. Med. Sci./ 1874; ' Lond. Med. Rec.' (abs. by myself in vol. i, p. 5), 1873. Idem, "Patho- logical Significance of Nematode Haematozoa/' 'Tenth Ann. Rep./ 1873, Calcutta (reprint), 1874; 'Ind. Ann./ 1875. Idem, " Remarks regarding the Haematozoa found in the Stomach of Culex mosquito/' ' Proc. Asiatic Soc. of Bengal/ March, 1878, p. 89. Idem, "Flagellated Organisms in the Blood of Rats " (being portion of a paper on " The Microscopic Organisms found in the Blood of Man and Animals," in ' 14th Annual Report of the San. Comm. with the Govt. of India'), in the ' Quart. Journ. of Micr. Science/ Jan., 1879. Idem (pub- lished since the present article was written), " The Nematoid Haematozoa of Man," ibid., April, 1879. Lima, J. F. da Silva (with Orevaux), ' Memoria sob re hematuria chylosa ou gordurosa des paizes quentes / extrahida da ' Gazeta Medica da Bah in/ 1876; repr. in 'Arch, de Med. Nav./ Dec., 1878 (see also Le Roy de Mericourt). Magalhaes, Pedro 8. de, " Filarias em estado Embryonario, encontradas n'agua tida como potavel (agua da Carioca)," '0 Progress Medico/ Dezembro, 1877, p. 57. Idem, " Nota sobre os nematoides encontrados no sedimento deposito pela agua (potavel) da Carioca," ' Prog. Med.,' 1 de Setemb., 1878, p. 577. Idem, " Caso de filariose de Wucherer/ ibid., 15 de Setemb., 1878, p. 589. Makina, M.D., " Filar ia in Chyluria," letter in 'Lancet/ Feb. 22, 1879, p. 286. Hanson, P., " Rep. on Haematozoa," ' Customs Gazette/ No. 33, Jan. March, 1877; see also 'Med. Times and Gas.' for "Nov. 10, p. 513, Nov. 17, p. 538, and Nov. 24, p. 563; Dec. 1, p. 589, 1877; also Jan., 1878. Idem, "Additional Cases;" ibid., March 2, 9, 23, 1878. Idem, " On Filaria sanguinis homing, and on the Mosquito considered as a Nurse," 'Proc. Linn. Soc/ March 7, 1878; see also report in 'Nature/ March 28, 1878, p. 439. Idem, " On Filaria sanguinis hominis, clinically considered in refe- rence to Elephantiasis, Chyluria, and allied Diseases," ' Rep. of Med. Soc. of Lond./ in 'Lancet/ March 30, 1878. Idem, " Further Observations on Filaria samjuinia hominis," "Med. NEMATODA 205 Rep." for April Sept., 1877, in ' Customs Gazette/ Shanghae, 1878. Idem, "The Development of the Filaria sanguinis homi- nis," 'Med. Times and Gaz.' for Dec. 28, 1878, p. 731. Men- court, A. Le Roy de, in Appendix to an art. entitled " Nouvelle phase de la question relative a la nature parasitaire de la chylurie. Decouverte du representant adulte de la ' Filaire de Wucherer/" par le Dr da Silva Lima, from the ' Gaz. Med. da Bahia/ Sept., 1877; see also the ' Lancet/ Jan., 1878, p. 22 (editorial notice). Moura, J. de, ( These de Concourso/ 1877. O'Neill, " On Craw-craw," ' Lancet/ Feb., 1875. Pareira, A. P., " On Bilharzia and Chyluria," ' Gazeta Med. da Bahia/ No. 9, 1877 (noticed in ' Lancet/ Feb. 2, 1878). Salisbury, J. H., " On the Parasitic forms developed in Parent Epithelial Cells of the Urinary and Genital Organs," ' Hay's American Journ./ vol. iv, 1868, p. 376. Santos, F. dos, in ' Gaz. Med. da Bahia/ March, l877.Sonsino, P., ' Eicherche/ &c., 1874; ' Delia Bilharzia/ &c., 1876; ' Sugla Ematozoi/ &c., 1876 (see Bibl. No. 12). Idem, "On the Diagnosis of Embryos of Filaria/' in his paper ' Sull' Anchylostoma duodenale / ' Estr. dall Impar- ziale/ 1878. Sousa, M. de A., ' Memoria sobre a Elephantiasis do escroto/ Bahia, 1878. Wucherer, 0., " Noticia Preliminar," &c., 'Gaz. Med. da Bahia/ Dec., 1868. Idem. ' Sobre Hema- turia no Brazil/ ibid., Sept., 1869; see also " Mericourt's trans. (De Fhematurie intertropicale observee au Brezil)," ' Arch, de Med. Nav./ p. 141, 1870, and the fuller references quoted in my memoir ; ' Linn. Soc. Journ., Zool./ vol. xiv, p. 368. Filaria Loa, Guyot. Although further examinations of this worm will probably result in placing it in some other genus than Filaria , yet it is by no means clear that Diesing was right in placing it with the genus Dracunculus. I therefore abandon the nomenclature adopted in my previous treatise. According to the surgeon, Guyot, who made seven separate voyages to the coast of Angola, these worms cannot be confounded with the Dracunculus. They are quite white, and relatively much thicker than guinea-worms. Under the title of Filaria oculi Moquin-Tandon has spoken of certain small nematodes as "not uncommon in the negroes of the Angola coast ;" and he gives other localities where it occurs. The worms are identical with those described by Guyot as dwelling beneath the conjunctivas of negroes at Congo and in the Gaboon region generally. The parasite is rather more than an inch and a quarter in length, being pointed at one end and blunt at the other. It is termed 206 PARASITES OF MAN Loa by the natives, who state that after a period of several years the worm voluntarily quits the organ. The disease is thus naturally cured. This parasite enjoys a tolerably wide geographical distribution, as it has been observed by Clot Bey in a negress who had come from the town of Monpox, situated on the banks of the Eiver Magdalena ; by Sigaud, who saw one in the eye of a negress in Brazil; by Blot, at Martinique, who saw two in a negress originally from Guinea ; by Bajon, who met with one in a little negro girl who had come from Guade- loupe ; by Mongin, wh.o found one in a negress who had been living in the Island of San Domingo ; and by Lestrille, who removed one from beneath the conjunctiva of a negro who came from Gaboon. BIBLIOGRAPHY (No. 24). Davaine, 1. c., p. 839. Guy on, ' Gaz. Med. de Paris/ p. 106, 1841, and in ' Micr. Journ. and Struct. Record/ p. 40, 1842, and in ' Dublin Journ./ vol. xxv, p. 455, 1839.Idem, ' Compt. Rendus/ torn, lix, p. 743, 1865. Guyotj in 'Mem. par Arrachait/ p. 228, 1805. Kuchenmeister, 1. c., s. 322. Lestrille, in Gervais and Van Beneden's ' Zool. Med./ 1859, also quoted by Davaine, 1. c., 2nd edit., p. 840. Leuckart, 1. c., s. 619. Moquin-Tandon, J../Zool. Med./ Hulme's edit., p. 363, 1861. Filaria lentis, Diesing. This is a doubtful species. The worm was first discovered by Nordmann, in a case of lenticular cataract under the care of Von Grafe, and it was afterwards found by Jungken in a similar case, as recorded by Sichel. There is also the instance described by Gescheidt, in which Von Atnmon operated, and from which brief descriptions of the worm have generally been taken. In this case there were three worms, two measuring about 5" and the third ^' in length. In Jiingken's case (exhibited by Quadri, of Naples, at Brussels) the worm was more than f" long. In another case, reported by M. Fano, the worm was somewhat less than " long. There is no certain evidence that any of these various worms had developed sexual organs in their interior. It is true that the reproductive organs were described in two of the worms observed by Gescheidt; but after a due consideration of all the facts I fear we must conclude that all the worms in question were sexually-immature and wandering nematodes, possibly referable to Gurlt's Filaria lacrymalis, as Kiichenmeister long ago suggested. BIBLIOGRAPHY (No. 25).Cobbohl, ' Eutozoa/ p. 332. Da- NEMATODA 207 vaine, 1. c., p. 821 et seq. Diesing, t Syst. Helm./ p. 625. Fano > f Traite des Malad. des Yeux/ torn, ii, p. 498 ; and in ' Rec. de Med. Yet./ p. 140, 1869 ; quoted by Davaine, p. 831. Gescheidt, Ammon's ' Zeitsch./ 1833, s. 435. Leuckart, 1. c., Bd. ii, s. 622. Nord 36. Idem, " On the Nervous System of Nematoda," from the German by Busk, ' Quart. Journ. Micr. Sci./ 1863. Schultze, " Case of Stuttering occasioned by Worms," from 'Med. Zeit./ in ' Med.-Chir. Rev./ 1837. Sheppard, "Case of A. lumbr. extracted from an Abdominal Abscess," ' Brit. Med. Journ./ 1861. Smith, J. N., " Thirty-nine Specimens of Ascaris lumbricoides in a Child," ' Bost. M. and S. Journ./ 1856. Spalding, P., " Case of Worms (100 Lumbrici), ibid., 1839. StocJcbridge, T. G., " Worm-trap (hooks and eyes), a New Remedy," ibid., vol. xxvii, p. 73, 1842-43 ; see also Anon., A. M. Stochbridge, W., "Mechanical Expulsion of Worms (by metallic buttons)," ibid., vol. xxviii, p. 419, 1843. Van Beneden, ' Animal Parasites/ 1. c., p. 95 ; see also Gervais. Villemin, " Case of Death from Worms (about 18 specimens of A. lumbr.), from ' L'Union Med.,' in the 'Lancet,' and rep. in 'Dubl. Med. Press/ vol. xxxv, p. 327, 1856. Weinland, in his ' Essay/ 1. c., p. 88, and in ' Troschel's Arch./ 1859, s. 283. Welsh, T., " Curious Facts respecting (symptoms produced by) Worms (A. lumbricoides")," art. ix in the ( Med. Papers communicated to the Massachus. Med. Soc./ vol. i, p. 87, 1790. Wendelboe, " Case of discharge of Worms (Ascarides ?) through the Skin," from ' Rep. of Roy. Soc. Copenhagen/ in ' Lancet/ 1836 ; see also Neilson. Williams, H. W., " Exhibition of a Lumbricus with a dress-hook attached," f Rep. of Bost. Soc. for Med. Improv./ in 'Bost. M. and S. Journ./ vol. Ivi, p. 163, 1857. Wilson, J., " On the prevalence of Lumbrici in China," in his ' Med. Notes on China/ London, 1846. Woodman, W. B., " Case of Convulsions, &c., arising from Lumbricoid Worms," 'Med. Times and Gaz./ 1863. Young, W., "Cases in which Lumbrici were evacuated by Ulceration through the Parietes of the Abdomen," 'Lond. Med. Gaz./ from ' Glasgow Med. Journ./ 1828 ; rep. in ' Lond. Med. and Surg. Journ./ vol. i, p. 564, 1828. 256 PARASITES OF MAN SECTION IV. PART I. ACANTHOCEPHALA (Thornheaded worms). Echinorhynchus gigas, Goeze. There is but one recorded instance of the occurrence of this entozoon in the human body. This is the oft-quoted case by Lambl, given in the ' Prager Yierteljahrschrift' for 1859. Lambl, indeed, described it as a separate species (E. hominis), but as the worm was a sexually- immature female, its identification with E. gigas, notwith- standing Schneider's great authority, can hardly be regarded as absolutely certain. The worm was found in the small intestine of a boy of nine years, and measured only rather more than the fifth of an inch in length. As Leuckart hints, the worm may be Echinorhynchus angustatus, or possibly the E. spirula, a species found in various South American apes (Cebus and Jacchus), and also in the Barbary ape (Inuus). In 1872, Welch, unaware of Lamb I' s case, announced the discovery of " the presence of an encysted Echinorhynchus in man/' The minute parasite found by him occurred in a soldier, thirty-four years of age, who died at Netley, but who had contracted the worm in India. " It was situated in the jejunum, immediately beneath the mucous coat, and formed an oval prominence in the interior of the gut." Speaking with great confidence, this able microscopist further remarks : " The character and arrangement of the booklets unequivocally shadowed forth a species of Echinorhynchus for the first time discovered as a representative of the Acanthocephala in the human body." Along with his elaborate description Welch gives several figures ; but these, so far from producing con- viction as to the accuracy of his inferences, have unfortunately led me to believe that the parasite in question would be more properly referred to the Pentastomidce. But for Heller's acquiescence I 'might have more fittingly noticed this worm elsewhere. Davaine falls into the same view, and moreover accepts Lewis's " Echinorhynque du Chien," which I have shown to be a nematode (G heir acanthus robustus). It is thus that serious errors creep into the literature of parasitism. In the adult state the female Echinorhynchus gigas is a huge species, occasionally reaching two feet in length, with a breadth of one third of an inch. The male rarely exceeds three inches. This worm is common in swine, both wild and ACANTHOOEPHALA 257 domesticated. According to Schneider the embryos take up their residence in the grubs or larvae of the cockchafer (Melo- lontha vulgaris), a discovery which very readily explains the manner in which hogs become infested. Whether E. gig as be a human parasite or not, it is certainly very injurious, not to say destructive, to swine. Although this parasite must be quite common in England I have experienced great difficulty in procuring specimens. In the second book of this work I shall give some interesting particulars furnished by the memoir of Prof. Yerrill and privately by Mr George Wilkins. (See ' Parasites of the Pachydermata'.) BIBLIOGRAPHY (No. 35). Blanchard, in ' Cuvier's Eegne Animal/ tab. 35 (good fig.), and in ' Ann. d. Sci. Nat./ ser. xii. Bremser, ' Icones/ tab. vi. CobboJd, " Parasites of the Hog," the ' Veterinarian/ 1875. Idem, ' Manual/ 1. c., p. 123. Davaine, 1. c., ' Syn./ p. 83. Diesing, 1. c., ii, p. 2. Dujardin, 1. c., p. 503. Goeze, 1. c., s. 143 (good figs.). Gurlt, 1. c., s. 367. Heller, ' Darmschmarotzer/ 1. c., s. 663. Lambl, 1. c., supra; Feb., 1859Leuckart, 1. c., Bd. ii, s. 729; also in ' Bibl. Univ.' for March, 1863, and in ' Ann. Nat. Hist./ vol. xii, 1863. Owen, 1. c., in ' Todd's Cyclop/ (figs, after Cloquet). Rudolphi, ' Synops./ pp. 63 and 310. Schneider, in ' Arch. f. Anat. und Phys./ 1868. Idem, in ' Sitzungsb. der Oberhess. Gesellsch. f. Nat./ &c., 1874 (quoted by Leuckart) ; see also ' Ann. Nat. Hist./ 4th series, vol. vii, p. 441, 1871. Verrill, ' The external and internal Parasites/ &c., 1. c., p. 109. Welch, " The presence of an Encysted Echinorhynchus in Man," ' Lancet/ Nov. 16, p. 703, 1872. Westrumb, < De Helm. Acanth.' (good figs.), 1821. SECTION IV. PAKT II. SUCTOEIA (Leeches) As explained in the Introduction we must regard the Leeches and many allied forms of Suctorial Annelids as creatures pos- sessed of semi-parasitic habits. They are, perhaps, something more than what Van Benedeii styles "free parasites " an expres- sion which almost looks like a contradiction of terms. I cannot here, however, stop to discuss questions which lie, as it were, on the border-land of parasitology. Three species of leech are more or less commonly employed in medicine. These are the grey leech (Sanguisuga mcdicinalis, Savigny), the green-leech (8. officinalis, 17 258 PARASITES OF MAX Sav.), and the dragon-leech (8. interrupta, Moq.-Tandon). The two former abound in Central and Southern Europe, being also present in North Africa, the last named inhabiting Barbary and Algeria. So abundant are leeches in the country bordering the Mediterranean that during the invasion of Egypt by Napo- leon the French soldiers suffered seriously from their attacks. When the men lay down to drink, the leeches (Htemopis sangui- sorba, Sav.) affixed themselves to their mouths and nostrils, producing serious distress. They also attacked horses, camels, and cattle. In like manner the Ceylon and Philippine Island leeches (8. ceylonica, Moq.-Tand., or 8. tagalla, Meyen), of which there are several varieties, prove exceedingly troublesome to Europeans. These leeches, not being aquatic forms, occupy woods and damp places. Unless the limbs of travellers are well protected, the presence of the blood-suckers is soon dis- covered by the trickling of blood from the limbs and lower part of the body. The leeches even sometimes creep up to the neck and other adjacent parts. These " free parasites " also attack horses, causing much loss of blood. Terrestrial leeches abound more or less in all warm countries. Sir J. Hooker encountered them in the Himalayas, and they are common in China, Japan, Java (8. Javonica, Wahlberg), and other eastern parts. They likewise abound in Brazil and Chili. The Ameri- can leeches for the most part belong to the genus Hsementeria (H. Mexicana, H. officinalis, and H. Ghiliani, Filippi). The last named is common in Brazil, the other two being Mexican forms. Another species, which is blind, has been found in Brazil by F. Miiller (Cyclobdella lumbricoides) . Not only the above-named species, but also many other kinds of leeches are in the habit of attacking man and the domestic animals, but the subject is too extended and special to be fully dealt with in this work. Almost a legion of species are known as exter- nally parasitic upon Fishes, Chelonian and Batrachian reptiles, Crustaceans, and Echinoderms. BIBLIOGRAPHY (No. 36). Blainville, 'Diet, des Sci. Nat./ torn, xlvii, p. 257. Brandt (und Ratzeburg), ' Medicin. Zoo- logie/ Bd. u.Brightwell, 'Ann. and Mag. Nat. Hist./ ix, 1842. Diesing, ' Syst./ vol. i, p. 465, and " Revis. der Myzelminth. (Abth. Bdellideen)," in ' Sitzungsb. der math.-nat. Cl. d. k. Akad. der Wissensch./ Bd. xxxiii, s. 473. Ebrard, '' Compt. Rend./ 1856, p. 1012. Idem, 'Monogr. des sangues Med./ 1857. Filippi, De, ' Mem. Accad., &c., Torino/ and in ' S. und AOANTHOOEPHALA 259 K. Zeitsch./ 1829. Idem, " Nuovo genere," &c., in ' Gaz. Med. Lombard/ 1849. Grille, o Womb (?) 1 Abdominal cavity. 1 Situation not recorded. ~ & 03 ;5 ^= .s a II Total annual deaths. 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 17 6 10 4 19 17 21 29 23 5 8 2 6 3 3 10 7 1 8 1 1 1 1 2 1- 1 2 2 7 1 4 1 2 6 2 4 200 2(0 33 22 17 15 29 29 41 47 36 38 1 i 1 1 2 "2 1 "a i 1 1 ... 3 1 3 i 1 1 Totals 166 53 7 5 2 3 2 1 1? 13 31 99 aa 307 inlOyrs (a) Lungs and kidneys. (i) In two instances liver and lungs; in the third case liver and brain. (c) Lungs and liver. (d) Lungs and abdominal cavity. (e) In three cases liver and lungs; in one kidney and abdomen; in another liver, lungs, omentum. (/) Liver and lungs. (g) One liver and lungs ; the second case lungs and heart. (A) Three cases liver and lungs; one liver and kidney. . (i) Liver and lungs. Such are the returns as recorded by Dr Thomas. If a com- parison be instituted between the data supplied by his decade- report and those supplied by the decade-report which I have previously adduced (p. 123), it will be seen that as regards the returns for the years 1868-72, inclusive, both reports are in perfect agreement. Of still more interest also is the circum- stance that whilst, on the one hand, out of the total of 307 deaths given in Dr Thomas's table, 116 occurred during the first semi-decade (i.e. from 1868 to 1872, inclusive), on the other hand, no less than 181 deaths occurred during the second semi- decade (i.e. from 1873 to 1877, inclusive). This increase of 45 deaths during the later semi-decade is very significant. It points either to the fact of more careful returns having been made, or to an actual increase in the fatality of the disorder. Possibly both the causes alluded to operated to affect the returns. Be that as it may, Dr Thomas's record is highly instructive, and should stimulate the profession in England to supply our Registrar- General with more precise data wherewith to construct his annual reports. BOOK II. PARASITES OF ANIMALS. IN dealing with this division of the subject it will be impos- sible to give more than the faintest outline. Let it be borne in mind that quite as much information might be offered by me respecting the parasitism of each of the commoner domestic animals as has been already advanced in regard to the helmin- thism of man. That would by no means exhaust the subject. Thus treated, a score of volumes, each equal in size to this, would barely suffice to cover the whole ground of Parasitology ; and yet there are not wanting intelligent persons who regard Helmin- thology as unworthy of their attention. These persons form a far too prevalent type of educated ignorance, and unfortunately, it is just this class of people who enjoy the prerogative of edu- cational responsibility. Even our metropolitan scientific insti- tutions, expressly raised for the purpose of diffusing useful knowledge, shrink from the revelations of parasitism. Domi- nated by the miserable conception which judges that the life-history of a worm cannot prove either interesting or instructive to their audiences, they let slip the acquisition of scientific data, a knowledge of which might enable them to combat successfully some of the most terrible evils to which human flesh, in common with that of animals, is heir. In the following few pages many new points of departure for fresh scientific work will inevitably be suggested ; and if I only succeed in conveying to the working student an adequate grasp of the whole subject, especially in its bearings on the welfare of the higher domesticated animals and man, I shall have accomplished all that I can reasonably hope to do within the restricted limits of space at my command. QUADRUMANA 289 SECTION I (MAMMALIA). In dealing with this class of hosts, exclusive of man, I shall notice the entozoa of the various orders successively, taking the arrangement which I employed many years since when writing the Mammalian Division of a popular treatise called the ' Museum of Natural History/ The internal parasites of those orders which happen to embrace important domesticated animals will necessarily receive more attention than the others; some notice of the ectozoa being likewise added. PAET I. QUADKUMANA (Monkeys). Monkeys are less afflicted with flukes than most animals. The species known to me are Distoma laciniatum , found by Brongniart in the pancreas of Simia maimon ; D. orbiculare and Amphistoma emarginatum, from the intestines of Cebus trivir- gatus ; and Bilharzia hcematobia, a single specimen of which I obtained from Cercopithecus fuliginosns. The monkeys of the Old World rarely harbor full-grown tapeworms, but Cysticerci are abundant (Cyst, tenuicollis, C. cellulosa, C. pileatus, C. crispus). The common hydatid (Echinococcus polymorphous) has been found in many of the Simiae, and by myself in a Madagascar lemur (L. macaco). Dr Leidy also obtained three hydatid cysts from a large monkey. On the last day of the year 1857 I obtained some polycephalous hydatids (Coenurus lemuris) from a ring- tailed lemur. They infested the liver, being more abundant in the lungs. They occupied both sides of the chest. Loose and detached specimens also existed in the cavity of the right pleura. Most of those occupying the chest were connected to the pleura, forming vesicular, semi-transparent masses, varying in size from a filbert to a large walnut, many being united in bundles of much larger size. One of these masses is here drawn (1, fig. 54). It consists of four large Coenuri, their combined pedicles forming a single stalk. A fifth hour-glass-shaped rudimentary Coenurus is also visible. Every Coenurus supports a variable number of lobules, each lobe sup- porting one or more papillae. Here and there the papillae resemble chains of beads. No trace of tapeworm heads could be seen, but under a half-inch objective glass, I found some flat papillae presenting oval depressions at the surface (2, fig. 54). 19 290 PARASITES OF ANIMALS On examining some of the larger papillaa they were found to consist of membranous layers folded one within the other. These were carefully dissected and examined with the aid of needles, when each one showed in the centre a well-formed FIG. 54. Ccenurus lemuris. 1, Coleny; 2, portion of the ectocyst (enlarged) ; 3, scoler- heutl (magnified 40 diameters) ; 4, hooks (magnified 260 diameters). Origin*!. tapeworm head with four characteristic suckers, and a promi- nent rostellum supporting a double coronet of hooks, thirty-two of the latter in all (3, fig. 54). The hooks displayed a marked disparity of size and form. Each hook showed conspicuous anterior and posterior root-processes, the larger set of hooks individually measuring about $" and the smaller . campanulatum) , besides which there is the winged species occupying the small intestines (Holostoma alatum). This latter is also found in Canis azarce. The tapeworms of the dog are not only numerous, but also particularly injurious, alike to their bearers and to mankind. By experimental research we have ascertained the sources of most of the Tanice. The serrated species (T. serrata) is derived from Cysticercus pisiformis infesting hares and rabbits. This is common in sporting animals, owing to the careless practice of allow- ing gamekeepers and kennel masters to throw the fresh viscera of the inter- mediate hosts to the dogs. I have witnessed this stupid habit in the field. The cucumerine tapeworm (T. cucume- riiui) is, by most observers, considered to be identical with the T. elliptica of the cat. I regard it as a variety. This delicate species is excessively common and is now, through Melnikow's dis- covery, known to be derived from the louse of the dog (Trichodectes latn*). This circumstance affords a curious illus- tration of the fact that an ultimate host may carry the intermediate host upon its back. As regards the relative prevalence of these tapeworms in England, it may be said that whilst T. serrata occurs almost entirely in our harriers, greyhounds, sheep-dogs, and lurchers (taught to "pick up- hares), the T. cucumerina is liable to infest any variety of dog, and probably infests nearly 70 CARNIVOBA 301 per cent. According to Krabbe the prevalence of the last-named species is 57 per cent, in Iceland and 48 per cent, in Copenhagen, whereas the T. serrata is almost absent from those countries. The gid tapeworm (T. coenurus) is derived from the ordinary gid hydatid infesting the brains of sheep and lambs. The polycephalous bladder-worm (Coenurus cerebralis), so familiar to agriculturists and veterinarians, is often confounded with the ordinary hydatid infesting ruminants. Ccenuri infest the soft parts of rabbits, but it remains to be shown whether they are the same species. Possibly the Gcenurus cuniculi is merely a variety. The gid tapeworm is not very abundant in England. In Denmark it appears to be rare, occurring in 1 per cent, only ; but in Iceland Krabbe found it in 18 per cent. In common with other helminthologists, I have frequently reared this and the serrated species by worm feedings administered to dogs. The lettered tapeworm (T. Utter ata) is very commonly spoken of as the Tanm canis lagopodis. It was so named by Viborg, but I prefer the more distinctive nomenclature of Batsch. We know nothing, for certain, respecting the source of this entozoon. It is rare if not altogether wanting in Denmark, but abundant in Iceland (21 per cent,). I have obtained specimens from a cheetah ( Canis jubatus) which died at the Zoological Gardens, and Mr W. H. Jackson, of Oxford, found it in a cat. The worm is certainly not confined to the Arctic fox (0. lag opus.). A well-known tapeworm infests the fox which has not yet been noticed in the dog. This is the Tcenia crassiceps, whose scolices (Cysticercuslongicollis) reside in the viscera and soft parts of field mice and voles (Arvicola arvalis, A. terrestris, A. amphibius) . This relationship was pointed out by Leuckart. Another tapeworm (T. opuntioides) mentioned by Rudolphi as occurring in the wolf,*seems to be of doubtful authenticity. A formidable and not uncommon tapeworm is Ttenia marginata. This large species occurs in at least 25 per cent, of English dogs, whilst in Iceland its prevalence reaches 75 per cent. In Den- mark about 14 per cent. only. It is well known that the larval or scolex stage (Cysticercus tenuicollis) of the margined tapeworm resides in the sheep and dog. In a feeding experiment with five examples of this bladder worm I reared five strobiles of ten days' growth. These imma- ture tapeworms were each one inch long. By far the most important tapeworm of the dog, however, is the hydatid-forming species (T. echinococcus) . This remarkable entozoon is the sole 302 PARASITES OF ANIMALS cause of the terrible echinococcus disease, so prevalent in Iceland and elsewhere. Experimental research, initiated by von Siebold, has explained its origin ; Van Beneden, Zenker, and others have also experimented successfully. Rarely attaining a length of J" , the perfect strobile is made up of only three proglottides in addition to the head, the lowermost segment being sexually mature. As hydatids (Echinococcus veterinorum or E. hominis) are found in a great variety of animals as well as in man, and as these bearers form so many kinds of intermediate hosts, it is easy to understand how readily dogs and wolves may acquire the sexually-mature tapeworm. I am in possession of hydatids from the liver of a clouded tiger (Fells macroscelis). In England the Tcenia echinococcus is excessively rare, and has not been seen in any dog which had not previously been subjected to a feeding experiment. Mr Nettleship succeeded in rearing large numbers. In Iceland, Krabbe found dogs to be infested to the extent of 28 per cent., a proportion fully explaining the prevalence of hydatid disease in that country. The remaining tapeworms of the dog belong to the genus Bothriocephalus ; of these, the broad tapeworm (B. latus) is best known, because it infests man. Diesing has described a variety found in the Pomeranian dog as a separate species (Dibotlirium serratum). The museum of the Royal Veterinary College contains a very perfect specimen of B. latus from an English dog, but the parasite is of rare occurrence in this country. It is generally supposed that this tapeworm is derived from the consumption of fish belonging to the salmon and trout family, but Dr Fock, of Utrecht, thinks that the bleak (Leuciscus albumus) is the usual intermediate host. I have already discussed this question at some length. Experimental proof is still wanting. In addition to B. latus the dog is liable to harbor B. cordatus, B. f'uscuSj and also two varieties of the last-named species (7?. dubius and B. reticulatus t Krabbe). Taking the pit-headed tapeworms as a whole, their prevalence in Iceland is not con- siderable, amounting to about 5 per cent. only. Lastly, it may be mentioned that instances are recorded of the occurrence of the hog-measle (Cysticercus celluloses] in the dog. Though many have felt sceptical on this point, Grurlt's authority is not to be lightly set aside, confirmed, as it has been, I believe, by MM. Megnin and Leblanc. Passing to the round worms it may be said that Ascaris mar- ginata is, at the best, a mere variety of A. mystax of the cat, CARNIVOBA 303 with which must also be placed A. leptoptera of the lion and other felines. The lateral appendages noiT only vary in breadth in these three forms, but also in the specimens obtained from each host. I have encountered examples in a dog, which measured more than six inches in length. The worm is excessively common in England, occurring in probably not less than 75 per cent., whilst in Denmark it occurs in about 24 per cent. According to Krabbe it is rare in Iceland. Its presence is at all times more or less injurious to the bearer, being a frequent cause of sickness, colic, convulsive fits, and paralysis. Occa- sionally the worms prove fatal to dogs by wandering into the trachea. At the Eoyal Veterinary College, in 1864, a litter of six puppies, of only three weeks growth, died rather suddenly in consequence of the presence of these worms in the stomach and small intestines. So far back as. the year 1684 Redi de- scribed round worms from the walls of the oesophagus of a dog. These were afterwards noticed by various observers in tumours of the mucous membrane of the stomach. Owing to their red color, derived from the ingested blood of the host, the species was named Spiroptera sanguinolenta. In 1867 I suggested that the minute Filariae found by Grube and Delafond in the blood of dogs would probably turn out to be referable to this species. The researches of Lewis have proved that this suppo- sition was correct. To be sure, other nematoid hsematozoa, of microscopic dimensions, occur in the dog, but those described by Grube and Delafond may be referred to Spiroptera. These authors estimated their number in the canine host to vary from 11,000 to upwards of 200,000. In one instance Messrs Grube and Delafond found six worms lodged in a clot occupying the right ventricle of the heart. Four were females and two males. Although they were described as representing an altogether new species, which they termed Filaria papillosa hcematica canis domestici, I think there can be little doubt that they were examples of Spiroptera sanguinolenta not fully grown. The writings of Lewis abound with interesting details respect- ing the structure and development of this worm, and as much may be said of the writings of Manson and Welch concerning the cruel threadworm (Filaria immitis, Leidy) occupying the right cavities of the heart. I was first made acquainted with this entozoon in 1853, by examining specimens in the possession of Prof. Hughes Bennett of Edinburgh ; at which time also I was put in possession of a valuable MS. (since lost) describing 304 PATCASTTES OF ANIMALS the ravages of this entozoon in the dogs of China. I have since received numerous vermini- ferous hearts both from China and Japan, and also some heart-worms from Charleston, U. S , sent by Mr M'Innes. In a recent communica- tion, Dr Manson has spoken of this worm as if it were comparatively harmless, but all the evidence I long ago received through the late Mr Swinhoe, formerly H. B. M. .-niaria im^iiu Tail of male. Consul at Amoy, through Mr Dare's Enlarged. Original. . , i -r^ ^ , i i letters enclosing Dr Urton s valu- able observations (addressed to the editor of the ' Field'), through the lost MS. above alluded to, through Dr Lamprey's statements, and through many other sources, lead to the very opposite conclusion. No doubt the canine hosts do for a time appear to be little inconvenienced by their nematode guests, but sooner or later the most distressing symptoms set in. As in Hoysted's case (quoted below) the convulsive spasms may occasion death in a few minutes, but frequently they last for hours or days, with more or less prolonged intervals of relief before the final struggle. Some other filariform nematodes have been imperfectly described. Of these, Gescheidt's Filaria oculi canini (F. iris- pinulosa, Diesing) was probably a sexually-immature worm, and the same may be said of the encysted worms found by Mr Mather in the mucous coat of the intestines and in the liver ducts and acini (Filaria hepatica, Cobbold). Of more interest is Leisering's haBmatozoon (Strongylus sululatus). These minute worms occupy the veins, the largest females not exceeding '' in length. They are viviparous, and thus form another source of embryonic haematozoa. A single drop of infected venous blood commonly carries from four to six mature worms. In this place may be mentioned Dr Osier's Strongylus canis bronchialis. The largest males measure J" and the females fully \" . In the worms sent to me by Prof. Osier I saw no evidence of strongyloid structure, and in his description he avoids all mention of the presence of any caudal hood in the male. I regard the worms as Filariae (F. Osleri, Cobbold). Very great interest attaches to them from the fact that they produce a destructive canine epizooty, resembling the ordinary CARNIVORA 305 " husk " or parasitic bronchitis of calves, lambs, and other domesticated animals. The only other genuine strongyle known to infest the dog is Eustrongylus gigas. This is a very common parasite in wolves. I have already spoken of this parasite at some length (Book I, p. 207), and can only further refer to the recently published case by Megnin (quoted below, and at full length in my paper in the 'Veterinarian' for April, 1879). The Museum of the Royal Veterinary College contains three fine examples of this worm coiled within the kidney of a dog, or rather within the renal capsule, for the substance of the organ is almost entirely wanting. These are from Bickford's case. Amongst the many good " finds " made by Lewis in India, not the least interesting is that appertaining to Cheir -acanthus robustus. Lewis, indeed, supposed that he had detected Echi- norhynchi in chestnut-sized tumours of the walls of the stomach, but, as I pointed out at the time, the parasites were entirely destitute of Acanthocephalous structure. As is well known, this curious nematode infests various felines, such as the wild cat, puma, and tiger. In addition to the above canine nematodes we have the wrinkled threadworm (Trichosoma plica) infesting the bladder. This is of much more frequent occurrence in the fox. In the list Trichina spiralis must also be included, although, so far as I am aware, it has only been seen in dogs that have been subjected to feeding experiments. Another nematode common to the fox and dogs, and infesting the caecum, is the whipworm (Trichocephalus depressiusculus). It is very rare in the dog. Lastly, there is the important little strongyloid worm generally known as Dochmius trigonocephalus. At the hands of Leuckart the general structure and development of this entozoon have received complete elucidation. It infests the small intestines, and is found alike in the fox, wolf, and cheetah. It has also been obtained from Canis lag opus and 0. azarae. Dr Krabbe did not encounter this worm in Icelandic dogs ; nevertheless, he obtained it in a blue fox which died in Kjoerbolling's menagerie, and which had come from Iceland. In Danish dogs it occurred in less than 2 per cent. The embryos of this worm are rhabditiform and possess three long bristle-like teeth, the slender tail being furnished with a distinct appendage at the tip. They develop in moist situations, where they feed freely, grow rapidly, and change their skins, throwing off the caudal tip with the first month. It seems evident that they do not require a change of hosts, since Leuc- 20 30G PARASITES oi- ANIMALS kart succeeded in rearing the sexually-mature DocJimii by introducing the rhabditiform larvse into the stomach of the dog ; moreover, his experiments upon water-snails belonging to the genus Phy$a gave negative results. Of Arachnidan parasites (Trachearia) infesting the dog, by far the most interesting is the well-known Pentastoma tanioides, shown by Leuckart to be the adult condition of the still better known Pentastoma denticulatum. It resides in the nasal sinuses. As already mentioned in a former part of this work, these parasites present four marked stages of growth, namely (1), the embryo, (2) the pupa, (3) the active larva (P. denticu- latum), and (4) the sexually-mature worm. As the eggs and their embryonic contents are lodged in the nasal mucus of the dog, and are commonly distributed by the act of sneezing on the part of the animal, the sources of infection are not far to seek. Clearly the larvaB usually get introduced to the bodies of man- kind and herbivorous animals by the ingestion of unclean vege- table matter. The embryos set free in the stomach bore their way to the liver and other viscera, in which organs encystation and moulting subsequently take place. The fondling of dogs infested by pentastomes may prove dangerous by a more direct transference of the eggs to the hands and mouth. As regards the dog, the adult parasite has been known to prove fatal. A very striking instance of this kind was recorded by Prof. Dick, where the worms wandered into the trachea producing asphyxia. The ectozoa of the dog, though not numerous as species, are of importance in relation to mange. The follicle-mites form a family by themselves (Demodicidce) , and, as already observed, those infesting the dog and cat are, alike, mere varieties of the human species (Demodex folliculorum, var. caninius and var. cati). Whilst the human parasite restricts itself to the face, the canine variety (fig. 52) will occupy any part of the dog's body. The follicle-mite of the cat, however, usually confines itself to the ear. According to Megnin, to whose beautiful monograph we owe so much, two or three dozen of these parasites may be found occupying a single follicle of the dog. Acne-like pustules are thus formed, and when they are very numerous death may result from the excessive irritation, which is usually accom- panied with depilation. An interesting example of this kind recently occurred at the Royal Veterinary College. In regard to the ordinary mange-mite (Sarcoptes canis, Gerlach) M. Megnin points out that it is in all respects identical with the human CARNIVORA 307 itch-insect. In the wolf and fox, however, the same species forms well-marked varieties (S. scabiei, var. lupi and var. vulpis) . As regards true insect parasites and tormentors of the dog, I can only allude to a few of them, In tropical America dogs are said to be attacked by the larvae of a species of gad- fly (CEstrus canis), whilst in Africa they are often fatally bitten by the tsetse (Glossina morsitans). In addition to the flies (Diptera), several kinds of fleas (Aphaniptera) frequently prove troublesome (Pulex canis, P. martis, and P. penetrans), and the same may be said of certain lice (Hemiptera). The common louse of the dog (TricJiodectes latus) proves especially noxious to young puppies. Of the two other species, namely, Hcemato- pinus piliferus and H. canis, the former is tolerably common, whilst the latter is comparatively rare. This species is also found on the ferret. A new form of mite (Chorioptes ecaudatus), infesting the ears of the ferret, has recently been described by M. Megnin. I have already referred to several of the parasites of the cat- tribe (Felidae), but some others require notice. Only two flukes (Amphistoma truncatum and Hemistoma cordatum) have been described as infesting the cat. Of the tapeworms, Taenia crassicollis is the best known. This is derived from Cysticercus fasciolaris of the mouse and rat. It is not uncommon to find this scolex in the sexually- immature tasnioid state in the liver, measuring six or seven inches in length. An exceedingly interesting communication by Dr Romano, of Gemona (Frioul), demonstrates the possibility of severe feline epizooty as due to this entozoon. As I gather from an account given in the journal quoted below, " during the summer of 1876, Dr Romano was informed by his confrere Dr Leoncini, a physician practising at Osoppo, that for about a fortnight most of the cats in a certain hamlet of the town had died without appreciable cause after presenting the following symptoms : Gradual wasting, with complete loss of appetite, retracted abdomen, slight diarrhoea at first, then constipation, abundant saliva, contraction of the elevating muscles of the upper lip in some subjects, great pros- tration of strength, loss of the visual faculty. Some of the feline patients no longer heard or appeared no longer to hear their master's voice ; some vomited and seemed to experience relief, for the appetite improved, but they soon died like the others. Nervous phenomena, epileptiform convulsions, and more frequently colic, also showed themselves. Having visited the 308 PARASITES OP ANIMALS locality (of the outbreak), Dr Romano could not at first pro- cure any corpses for the post-mortem examination, for the children had thrown them into the Tagliamento, which flows at the foot of the fortress of Osoppo. It was only after the lapse of some days that he was able to open one of the animals which had just succumbed. The principal evils were remarked in the stomach, the walls of which were retracted and formed the seat of a catarrhal inflammation, from the products of which a long, white, flat worm was removed with care for examination. All the other organs were in good condition. The examination of the helminth in the stomach, made with the help of Dr Leoncini and Fachini, showed that the flat worm (white, and with the body divided into rings, 12 centimetres long, and 5 or 6 millimetres broad) had all the characters of the taenias, and this was confirmed by a microscopic examina- tion of the head. A few days later Dr Romano made an autopsy of two other cats. In one of the corpses he noted the alterations described above, and found a taenia smaller than tho first ; in the other the same lesions without any helminth. This negative circumstance very naturally disconcerted Dr Romano, but several people of the place came to assure him that they had seen their cats, during the course of the malady, after violent and repeated efforts at vomiting, throw up a sort of white cord, which they recognised as corresponding with the taenia he showed them. Thus confirmed and reassured in his diagnosis, Dr Romano sought to identify the species." In this connection it is specially interesting to note that " during the whole summer the inhabitants of Osoppo had been over-run by bands of rats proceeding from the fortress. They were com- bated by means of cats, and it was the best hunters among the felines that succumbed. Here was, therefore, a striking relation of cause and effect which could not be gainsayed." Dr Romano communicated his observations to the National and Royal Veterinary Society, but by an error in the report the species appears to have been described as Tcenia tenuicollis instead, of T. crassicollis. t In this connection I have only further to add that the wild cat is infested by a tapeworm scarcely an inch in length (Tania lineata). A species of Bothriocephalus (B. decipiens) likewise infests the domestic cat, in common with most of the wild felines, such as the tiger, puma, ounce, and jaguar. Dr Bancroft brought me a specimen from an Australian cat. The nematodes of the cats are very CABN1VORA 309 abundant. Dr Bellingham found a trichosome (T. felis cati) in the urinary bladder of the wild cat. This is probably identical with T. plica. A. tolerably common nematode is Dochmius tubaformis, which occurs not only in the cat but also in the leopard, puma, jaguar, ounce, panther, and also in Felis tigrina and F. mellivora. In the last-named and in other Brazilian felines an echinorhynchus (E. campanulatus) was found by Natterer. A strongyle (Sclerostoma dispar) infests the lungs of the puma. A species of spiroptera (S. subcequalis, Molin) infests the oesophagus and stomach of the lion and tiger. Redi also noticed a species of Filaria beneath the skin of the lion. Physaloptera terdentata (Molin) and P. digitata (Schneider) infest the stomach of the puma. I can only allude also to Tania laticollis of the lynx, Pentastoma recurvatum, occupying the frontal sinuses and air-passages of the ounce, and Ligula reptans the subcutaneous tissues of the leopard. Lastly, there is the Olulanus tricuspis of the domestic cat. I have examined the lungs of three cats containing this parasite, which was first described as an entirely new species by Leuckart. The adult worms, only ' in length, occupy the walls of the stomach. Thence they are apt to migrate or stray into the lungs and liver, where they encyst themselves. When myriads of them are thus encysted a kind of nematode tuberculosis is set up. This disease I have elsewhere called olulaniasis. Ordinarily, however, the encysted condition of olulanus is to be found in the muscles of mice, which are thus said to be olulanised. Clearly, as Leuckart's experiments substantially prove, the domestic cat acquires the adult worm by catching and devour- ing olulanised rodents. Every now and then the disorder thus created produces a virulent and fatal feline epizooty. BIBLIOGRAPHY (No. 45). (Anonymous), "Curious Note on two Taenia from the Dog (asserting that neither strong whisky nor boiling water would kill them)," f Med. Commentaries/ vol. xvi, p. 370, 1791. Araujo, A. J. P. 8., "A Filaria immitis e F. sanguinolenta no Brazil/? f Grazeta Medica da Bahia/ Julho de l878.Baillet, G., " On Dochmius, and on a Worm found in the Heart and Vessels of a Dog," from ' Journ. Yet. du Midi/ in the ' Veterinarian/ p. 549, 1862. Baird, W., " Note on the Spiroptera sanguinolenta found in the Heart of Dogs in China," ' Proc. Linn. Soc./ vol. ix, Zool. Div., p. 296, 1867. Balbiani (1. c., Bibl. No. 28). Beneden (see Van Beneden, below). Bickford (1. c., Bibl. No. 28). Chapman, 310 PAEASITES OF ANIMALS " On Ascaris mystax (leptoptera) in the Tiger and American Wild Cat/' 'Proc. Acad. Philad./ 1875, pp. 14 and 17. Cherry, E. F., " Worms in the Stomach of a Dog/' in the ' Farrier and Naturalist/ 1829, vol. ii, p. 303. Glamorgan, J. de, " Serpents dans les reins/' in his 'La Chasse du Loup/ 1570; see also Bibl. No. 28. Gobbold, " On the Prevalence of Entozoa in the Dog, in relation to Public Health/' ' Journ. Linn. Soc./ vol. ix (Zool. Sect., No. 37, p. 281), 1867; also in 'Lancet/ April 27, 1867, p. 521 ; and in supp. to ' Entozoa/ 1869. Idem, " Observ. on Entoaoa, with experiments in regard to Tania serrata and T. cucumerina," ' Linn. Trans./ 1858. Idem, " On some new Forms of Entozoa," 'Linn. Trans./ 1859. Idem, "Further Observ. on Entozoa, with Experiments," 'Linn. Trans./ 1861. Idem, " On Filaria immitis," ' Proc. Zool. Soc. of Lond./ Nov. 18, 1873, p. 736. Idem, " Observ. on Haematozoa," in the 'Veterinarian/ Oct., 1873. Idem, "Parasites of the Dog," in 'Manual/ 1874, 1. c., chap, ix, p. 86. Idem, "Description of a new generic type of Entozoon (Acanthocheilonema) from the Aard Wolf (Proteles)," 'Proc. Zool. Soc. of Lond./ Jan. 13, 1870. Idem, "On Distoma compactum," in 'Linn. Trans.,' vol. xxii, p. 363, 'Proc. Zool. Soc.,' March, 1861. Idem, various letters on " Canine Epidemics in relation to Lumbricoid Worms in Dogs," in the 'Field/ Dec., 1872. Idem, "Remarks on the Life-epochs (biotomes) of T. coenurus and T. echinococcAis," in a paper on ' Animal Individuality/ ' Journ. Linn. Soc./ Zool. Div., vol. viii, p. 163. Idem, " Worms in the Heart (Mr. M'Innes' specimen from Charleston)/' the 'Veterinarian/ Feb., 1875. Idem, "Note of Lewis' Discoveries," in 'Nature/ March 11, 1875, vol. ii, p. 363. Idem, "Remarks on Eustron- gylus gig as " in the 'Veterinarian/ April, 1879. Coles, E. C., " Worms in the Heart and (Esophagus of a Dog," ' Path. Soc. Rep./ March, 1878. Dare, J. J., " Death of Dogs from Worms in the Heart," the 'Field/ Feb. 24, l872.Davaine, 'Traite/ 1. c., 2nd edit., p. 290 (for refs. to lit. of Strongylus gigas). Delafond (with Grube), " Note on a Verminiferous kind of Blood of a Dog, caused by Haematozoa of the genus Filaria," from ' Ann. de Chimie et de Physique/ in ' Ann. of Nat. Hist./ vol. xi, 1843, and ' Comp. Rend./ in 'Lond. Phys. Journ./ p. 28, 1843; also from ' Gaz. Med./ in 'Med.-Chir. Rev./ vol. xxxv, p. 393, 1843-44 ; see also ' Edin. New. Phil. Journ./ vol. lii, p. 233, 1852, and 'Veterinarian,' vol. xviii, p. 216, 1845. Dick, "Worms the cause of Sudden Death in a Dog," the ' Veterinarian/ vol. xii, GARNI VORA 311 p. 42, 1840 (Pentastomes). Diesing, ' Syst. Helm./ vol. ii, p. 327 (Eustrongylus) . Ercolani, G. B., " Osservazione elmin- tologiclie sulla dimorfobiosi nei Nematodi, sulla F. immitis e sopra una nuova specie di Distoma del cani," ' Mem. Accad. Bologn., v, 1874-5. Frank (see Bibl. No. 28). Gay, /., Speci- men of Olulanus in Hunterian Museum, and marked in the ' Catalogue' "No. 1814A, Lung of Cat, pneumonic, from the presence of parasites." Gay, " Nematodes of Panther," in < Bering's Report./ 1873, from 'II. Med. Vet/ Herbst, "On Trichinae in the Badger," from ' Ann. des Sci. Nat./ in ' Assoc. Med. Journ./ 1853, vol. i, p. 491. Hoysted (and Sir J. Fayrer), "On Filaria sanguinis (really F. immitis)," ' Lancet/ March 1, 1879, p. 317. Jamieson (see Manson). Jardine (see Manson). Klein, J. T., " Worms found in the Kidneys of Wolves," 'Phil. Trans./ Vol. xxxvi, 1729,Krabbe, " Husdyrenes In- voldsorme," ' Tidsskrift for Veterinairer/ 1872. Leblanc, " Subcutaneous Tumour in the Dog, due to the presence of Strongylus gig as/' from f Recueil de Med. Vet.,' in ' Ediii. Yet. Rev./ Dec., 1863 ; see also Bibl. No. 28. Idem (see Megnin). Legros, " Haematozoa of Dogs," in ' Rec. de Med. Vet./ i, p. 947. Leisering, " On H0m. subulatum," in ' Virch. Archiv/ 1865 . Leuckart (see Bibl. Nos. 28, 29). Idem, (for development of T. serrata, &c.), ' Die Blasenbandwiirmer und ihre Entwicklung/ Giessen, 1856. Idem, ' Bau und Ent- wicklungsgeschichte der Pentastomen (especially P. ttenioides and P. dent.),' Leipzig, 1860. Idem, f In relation to the genus Dochmius/ see his standard work, 1. c., s. 433, and also 'Arch, f. Heilkunde/ Bd. ii, s. 212 (see also Parana). Lewis, T. R., f( On Nematoid Hasmatozoa of the Dog," ' Quart. Journ. Micr. Soc./ 1875, vol. xv. Idem, " On Filaria sanguinolenta, Echi- norhynchus, &c., from the Dog," in his oft-quoted ' Memoir/ Calcutta, 1874. Linstow, 0. von, " Ueber die Muskulatur, Haut und Seitenfelder von Filaroides mustelarum, v. Ben.," 'Arch, f. Naturg./ xl, s. 135 (with figs.). Idem, " Einige neue Nema- toden," &c., 'Arch. f. Naturg./ p. 293, Bd. xxxix. Manson, P., " On F. sanguinolenta and F. immitis/' in his ' Report on Haematozoa/ in the ' Customs Gaz./ No. xxxiii (with numerous figs.), Jan. March, Shanghai, 1877. (N.B. The same journal, Rep. No. 12, Gaz. No. xxx, contains remarks on worms in the heart of dogs by Dr A. Jamieson. The subject is also discussed by Dr Jardine.) See also ' Med. Times and Gaz.,' Oct. 20, 1877, p. 480. Mather, T., " Filaria found in the 312 PARASITES OP ANIMALS Intestines of a Dog/' ' Veterinarian/ vol. xvi, p. 434, 1843. McConnell, " On D. conjunctum," ' Lancet/ March 30, 1878, p. 476. Megnw, P. " On Myobia," 'Abhandl. ueber eine neue Gruppe von Acariden (u. s. w.)/ in ' Eevue f. Thierheilkundc/ Oct., 1878, p. 149. Idem, " Sur un parasite des oreilles chez le furet," ' Rec. de Med. Vet./ Oct., 1878. Idem (avec C. Leblanc), " Note sur le Cysticercus celluloses developpe chez le chien," ' Bullet, de la Soc. cent. vet. de Paris/ 1873. Idem, " Sur le 8trongylus gigas," Bullet, de la Societe Entom. de France, No. 3, 1879. Melnikow, N., "On Tania cucumerina," in 'Arch. f. Naturg./ 1869, p. 62. Miller, E., 'Six Cases of Strongyle in the Kidney of Putorius vison ' (quoted by Davaine from Museum of Boston, U.S.). M'Innes (see Cobbold). Molin, ' Nuovi myzelmintha/ s. 34, 1859. Idem, 'Una monog. del gen. Physaloptera (P. terdentata) / 1860, s. 17. Idem, 'Una monog. del gen. Spiroptera (8. subaqualis) ,' 1860, s. 13. Nettleship, E., " Notes on the Rearing of Tania ecliinococcus in the Dog from Hydatids, with some observations on the anatomy of the adult worm/' ' Proc. Roy. Soc./ 1866, No. 86, p. 224, with figs. Noseda, B., " Six Strongyles in the Kidney of the Agouara-gouazura or Puma," in Don F. de Azara's ' Qua- drupedes du Paraguay/ Paris, 1801 (see also Azara, Bibl. No. 28). Osborne, T. C., "Worms found in the Heart and Blood-vessels of a Dog (with symptoms of hydrophobia)/' ' Western Med. Journ.,' rep. in ' Bost. Med. and Surg. Journ./ vol. xxxvii, p. 448, 1847-48. Osier, W., "Verminous Bron- chitis in Dogs (from Strongyles)," 'Veterinarian/ June, 1877, p. 387. Owen, " On the Anatomy of Linguatala tanioides," 'Trans. Zool. Soc./ .vol. i, 1835, and in ' Lond. Med. Gaz./ 1835. Idem, "Anatomical description of two species of Entozoa, from the Stomach of a Tiger, one of which forms a new genus, Gnathostoma," ' Proc. Zool. Soc.,' part iv, 1836. Parona (and Grassi), " On a new Species of Dochmius (D. balsami)" ' Reale Institute Lombardo di Scienze e Lettere, Rendiconti/ vol. x, fasc. vi, 1877. Raynold, T. M., " Tapeworm in the Pointer and Spaniel," 'Veterinarian/ vol. xiv, p. 694, 1841. Romano, " Epizooty amongst Cats from Tcenia crassicollis," ' Giornale di med. vet. practica/ Aout, 1877, and in ' Journ. de Med. Vet./ Avril, 1878. Schuppert, M., "Mechanical Obstruction of the Heart (of a Dog) by Entozoa, causing Death," 'New Orleans Med. News and Hosp. Gaz./ Jan., 1858, also ' Bost. Med. and Surg. Journ./ vol. Ivii, 1857-58, and in ' Med.-Chir. Rev./ CAEN1VORA 313 1858. Stirling, " On the Changes produced in the Lungs by the Embryos of Olulanus tricuspis," ' Quart. Journ. Micr. Sci./ 1877, p. 145. Van Beneden, " On the Transmigration of the Entozoa " (in answer to MM. Pouchet and Verrier), from the French/ by Busk, in ' Quart. Journ. Micr. Sci./ 1862. Idem, " Researches on the Intestinal Worms/' from Van der Hoeven's abstr. in the f Nederlandsch Tijdschrift voor Geneeskunde/ in ' Ann. Nat. Hist./ vol. iii, 3rd ser., 1859. Idem, "New Obs. on the Development of the Intestinal Worms," from ' Compt. Bend./ in ' Ann. Nat. Hist./ vol. xiii, 2nd ser., 1854. Idem, " On Filaroides mustelarum," ' Mem. sur les vers intest./ J858, p. 267. Welch, "On Filaria immitis," ' Lancet/ March 8, 1873 ; also in ' Month. Micr. Journ./ Oct., 1873, p. 157 (with three plates). Wilson, W., " A Parasitic Worm infesting the Air Sinuses of the Weasel," ' Midland Naturalist/ May, 1878. Wright, " On Worms found in the Pulmonary Artery of a Dog," ' Lancet/ 1845, and in ' Veterinarian/ vol. xviii, p. 52, 1845. Youatt, " On Tumours (containing Entozoa) in the Stomach of a young Tiger," 'Veterinarian/ vol. x, p. 619, 1837; see also Owen on f Gnathostoina/ Idem, " Worms (Ascaris marginata) in the Nose of a Dog," ' Veterinarian/ vol. v, p. 337, 1832. PART V (PINNIPBDIA). Following the order of classification adopted in my descrip- tion of the Mammalia in the ' Museum of Natural History/ I proceed to speak of the internal parasites of the seals (Phocidce) and walruses (Trichecida). From their piscivorous habits one would naturally expect the seals to be largely infested with entozoa, and yet, though sufficiently victimised, they are not liable to entertain so great a variety of helminths as the fishes themselves on which they feed. The flukes observed in Phoca vitulina are Distoma acanthoides and Amphistoma truncatum, the latter occurring also in P. groe.nlandica. In another seal (P. barb at a) we have D. tenuicolJe. The nematodes are more numerous. The best-known is the maw-worm (Ascaris osculata), which seems to be always present in full-grown seals of every kind. In the years 1862-64 I conducted a series of experiments with the eggs of this worm. I reared embryos both in salt and fresh water, but the adminis- tration of the young worms to various animals led to no result. 314 PARASITES OF ANIMALS However, I succeeded in watching the growth of the embryos until they had acquired well-marked digestive organs and a length of -L", their size when emerging from the egg-shell in the water having been about jjg" only. The large strongyle (Eustrongylus gigas) has been found in various organs of the common seal. Of more interest are the Filarice found in the heart of seals, which in many re- spects resemble those obtained from the same situation in dogs. Professors Joly, Leidy, and myself, have each described a species, but ap- parently our descriptions all refer to one and the same parasite. It has also been seen by Camill Heller. The close correspondency in size and other characters of Leidy's Filana spirocauda and my Filaria hcbetata leaves little doubt as to their identity. As the worms were both originally noticed by Leidy and Joly in 1858, I cannot pronounce upon the question F.O. 59.-^m ". of priority of discovery. By Joly the worm ml?e. a i'r e H\ *;i[e" was called F. cordis phoccB. In Leidy's and Original - in my own specimens the males were four inches long, and the females six inches ; they extended up to 8" in some of the American examples. The worms found by Prof. Joly were all females. Professor Millen Coughtrey, who furnished me with the seal's heart, stated that it was obtained from a male hoodcap (Stemmatopus cristatus), a rare visitant of our British coasts. This seal was captured on the Cheshire side of the Mersey river. Leidy and Joly obtained their specimens from Phoca mtulina. In the common seal have also been found Ligula crispa, Schistoceplialus dimorphus, and Echinorhynchus strumosus. In other seals a not uncommon tapeworm of the Bothriocephalous type is that called Dibothrium Mans by Diesing. To Prof. Krabbe I am indebted for a specimen of Bothriocephalus fasciatus taken from Phoca hispida. There is a nematode of frequent occurrence in P. hispida and P. grcpnlan- dica. This is the Ophiostoma dispar of Rudolphi. In addition to the above I can only add that P. barbata is infested by Liorhynchus gracilescens, occupying the stomach, and by a tape- worm, Tetrabothrium anthoccphalum, which is found in the lower part of the large intestine. BIBLIOGEAPHY(NO. 46). Cobbold, "Description of F. hcbetata," EODENTIA 315 in ' Notes on Entozoa/ part i, sp. 3, ' Proc. Zool. Soc./ Nov. 18th, 1873, p. 741. Idem, " On Ascaris osculata," in ' Eeport of Experiments respecting the development and migrations of the Entozoa;' ' Brit. Assoc. Trans./ 1864, p. 114. Heller, C., in ' Schrift der zool.-botan. Gesellsch., 3 Wien, 1858, s. 83. Joly, " On a new Species of Hsematozoon of the genus Filaria, observed in the heart of a seal ; " from ' Compt. Rend. Acad. Sci./ 1856, p. 403, in ' Ann. Nat. Hist./ vol. i, 3rd ser., 1858 ; also abstr. in the ' Year Book/ 1859. Leidy, J., (E. spirocauda) in ' Proc. Philad. Acad./ 1858, p. 112. PART YI (RODENTIA). Though very numerous, the parasites of this order are chiefly interesting as embracing those of the hares and rabbits, moles, mice, rats, squirrels, and beavers. Some slight notice, however, will be given of the entozoa of each of the eleven families into which the order may be divided. The squirrels (Sciuridce) are liable to be infested by the common liver fluke (F. hepatica), and also, it is said, by a cysticercus (G. tenuicollis). I have never encountered this bladder worm, but in 1864 I described some polycephalous hydatids (Ccenuri) which I obtained from the viscera of an American squirrel. I think the host was of the same species (Sciurus vulpinus) as that from which Mr Chapman has since obtained an example of Echinorhynchus (E. moniliformis] . This worm also infests the hamster. A very small female round worm, probably a strongyle, was described by Rudolphi as Ascaris acutissima. It infests the caecum of the common squirrel, in which host a species of tapeworm is tolerably frequent (Taenia dendritica). The common European marmot is infested by T. pectinata, so abundant in hares and rabbits. I have also noticed it as occurring in the Canadian porcupine (Hystrix dorsata). The dormice (Myoxidte) are not much troubled with parasites, at least I have not encountered any in our common Myoxus avellanarius. In M. glis y however, a tapeworm, and at least one species of strongyle (S. gracilis), have been observed. Dujardin described very fully another strongyle (8. l&vis) from M. nitela, from the long-tailed field-mouse (Mua sylvatica), and from Arvicola subtcrraneus. The other species are Trichosoma myooci nitclte, and Opldostoma cristatum from 316 PARASITES OF ANIMALS Myoxus dry as, and M. muscardinus. The jerboas (DipodicUf), in common with the hamster and several species of true mice, are apt to be infested by Ascaris tetraptera ; and a small nematoid, apparently immature, was noticed by Otto in the intestines and in the abdominal walls and cavity of Dipus tetradaciylus. Mice, properly so called, are largely infested, as is also the hamster (Oricetus vulgaris), which I include in the Muridce. In addition to the parasites already mentioned, the hamster is infested by Tania straminea. Along with examples of this tapeworm I have received from Dr Murie some acepha- locysts found in a hamster which died at the Zoological Gardens. Flukes exist in the long-tailed field-mouse (Distoma vitta and D. recurvum), but I have not seen any in our common mice and rats. However, Dujardin describes a distome (D. spiculator) in the brown rat (Mus decumamis). One of the tapeworms observed in the mouse (M. musculus) is Tania pusilla, also found in the rat (M. rattus) and long-tailed field-mouse. The house- mouse likewise harbors T. microstoma and T. leptocephala ; and an immature cestode has also been seen in the abdomen, probably a species of Ligula. Various species of rat also harbor T. diminuta. In regard to the round worms one of the most common species is Ascaris oxyura. This not only occurs in rats and mice, but also in voles, water-rats, and many other rodents. The rodents' whip worm (Trichocephalus nodosus) is yet more common in the lemmings, rats, voles, and mice; another species (T. unguiculatus) , taking its place in hares and rabbits, and yet another (T. affinis) in the porcupine. Another nematoid, very common in mice, is Spiroptera obtusa, occupying the stomach. I have seen a mouse with its abdomen so dis- tended by their presence that the animal could scarcely run along the pathway where it was killed by being trod upon. According to Marchi, the young of this entozoon dwell in the fat surrounding the alimentary canal of the larva of an insect (Tenebrio molitor). When noticing the parasites of the cat I referred to Leuckart's interesting discovery of the relations subsisting between the adult Olulanus tricuspis, found in the stomach walls of that feline, and the immature encysted worms, found not only as wanderers in the cat itself but also in the muscles of mice. The olulanised mouse is thus an intermediate host. Rats and mice also play the part of intermediary bearers in the case of two other species of entozoa, namely, Trichina *>i rails and Tania crassicollis, the tsenioid scolex or larval EODENTIA 317 condition of the cat's tapeworm being familiarly known as Cysticercusfasciolaris. This sexually -immature tapeworm infests many other rodents, especially the voles (Arvicolidce) . In regard to Trichina it must not be forgotten that their presence in rats is not uncommon in some parts of Europe; and this circumstance may explain the recurrence of trichinosis (first in hogs and then in man) in certain outlying districts. Only in this way' can the Cumberland outbreak in this country be accounted for. Here I cannot dwell upon the subject, but in this connection I may observe that Bakody has in a very con- vincing manner described a new variety or species of Trichina, found by him infesting the walls of the stomach and intestine of rats. In the first instance he detected the worm in associa- tion with the ordinary T. spiralis, but afterwards separately. He also obtained it in fowls. The species should be called Trichina Bakodyii. Possibly the nematodes observed by Colin in 1863 also refer to this worm. They occupied tubercles in the liver of a rat. In regard to the beavers (Castorida) it appears that they harbor many species of round worms, and also several flukes, but they do not appear to have been very much studied. In Morgan's work on the American beaver there is a notice in which it is stated that Dr Ely found a very fine filamentous worm 40"' in length. This does not seem to correspond with Ascaris castoris (Rud.). He also speaks of large numbers of a slender white worm, 3" to 5" in length, found in the peritoneal cavity, and referable to the genus Filaria. This cannot be confounded with Trichocephalus castori (Bud.). Moreover, he describes a strongyle (Sclero- stoma) as infesting the colon, and especially the caecum. These all appear to be new to science. The Fasciola hepatica is occasionally found in the liver, but the most common helminth of beavers is Amphistoma subtriquetrum. Specimens of this worm may be seen in the British and Hunterian Museums. As regards the porcupines (Hystricidce) I have already men- tioned the occurrence of a tapeworm in the common species. The larval Pentastoma denticulatum has been found by Otto attached to the surface of the lungs, and R-edi, about two cen- turies back, noticed small nematodes lodged in tubercles of the oesophagus. The late C. M. Diesing obtained Trichocephalus affinis from the intestines. So far as I am aware, little or nothing has been said respecting the helminths of the Octo- dontida, Chinchillida, and Cavidce. Like other European 318 PARASITES OF ANIMALS investigators I have dissected guinea pigs (Cavia apercea) with- out finding any parasites ; but in Brazil a small species of ascaris (A. uncinata) was found by Natterer in this animal and also in the paca (Ccelogenys paca) The agoutis (Dasyprocta) harbor Trichocephalus gracili*. The entozoa of the duplicidentate rodents (Leporida) acquire importance from the fact of their abundance and from the intimate relation which some of them bear to parasites infest- ing the dog and other animals. Thus, the two commonest kinds of fluke infesting cattle (Fasc. hepatica and Dist. lanceo- latum) also attack hares and rabbits ; the former parasite often producing the rot disease, which is almost as fatal to the rodents as it is to the ruminants. Mutual infection occasionally results from this circumstance by the distribution of germs. All experiment-conducting helminthologists have reared Tania serrata from the Cysticercus pisiformis ; nevertheless, several English Manuals of Zoology persist in propagating the old error of Von Siebold, who supposed he had reared this tape- worm by the administration of Ccenuri. So far as I am aware, no feeding experiments have been conducted with the Coenuri of rabbits (C. cuniculi). These bladderworms infest the soft parts of the body, often producing tumours having a very unsightly appearance. For details I must refer to the papers quoted below. The Norfolk warreners call the infested hosts " bladdery rabbits/' Though apparently most abundant in the eastern counties of England, these diseased rabbits are by no means confined to that quarter. Through Mr Alston's help I have received specimens of Goenurus cuniculi from Ayrshire, Scotland. Probably this form of Coenurus occurs wherever rabbits live. In Italy a case is recorded by Perroncito from the abdominal cavity of a rabbit (coniglio). Every experi- menter is more or less familiar with the cestode larvae (C. pisi- formis) found wandering in the abdominal cavity. These were regarded as flukes by Kuhn (Monostoma leporis). I need hardly remark that the developmental and structural changes undergone by these Cysticerci during their residence within the rabbit have been exhaustively followed out and treated of by Leuckart. Without dwelling on this subject, I must in justice add that in this relation the special labors of Kiichen- meister, Van Beneden, Haubner, Wagener, Roll, Eschricht, and Moller played no inconspicuous part. My own efforts in 1857, and subsequently, were not unattended with success. It EODENTIA 319 therefore seems to ine, without prejudice to the recent experi- ences of De Sylvestre and others, that further experiments in this immediate connection are .unnecessary. As regards the nematodes of leporine rodents, probably the most important is Strongylus commutatus. This parasite, like its husk-produc- ing congeners, infesting calves and lambs, occasionally sweeps off great numbers of hares. Such an epizooty occurred in Thuringia in 1864. The most frequent intestinal parasite of rodents is probably Oxyuris ambigua, but Strong, retortaformis is tolerably abundant in the hare, and Trichocephalus unguiculatus is liable to occur in all leporines. I know nothing of the so-called Strong, strigosus of rabbits, but Bellingham found it in Ireland. Olfers and Natterer obtained a small ascaris (A. veligera) from Lepus braziliensis ; but I cannot help thinking that the large measle (Cysticercus macrocystis) described by Diesing as three inches in length, and obtained from the same rodent, must either have been Coenurus cuniculi or else another form of poly- cephalous hydatid. In reference to the ectozoa of rodents it may be said that they are very numerous. Acari infest rats and mice, and espe- cially leporines. Thus, in the mouse are found Sarcoptes notoedre, Bourguignon, var. muris, Megnin, Sarc. musculinuSj Koch, and Myobia musculi, Claparede. It is not very gene- rally known that wild rabbits are apt to be attacked by the common autumnal spider (Leptus autumnalis) , whence, as once happened with myself, they may be transferred to the human body. The ears of tame rabbits are sometimes covered with acari, which are easily destroyed by the cautious application of a mixture of carbolic acid and olive oil (one of acid to six of the oil). Kodents also harbor fleas. At a meeting of the Ento- mological Society in 1875 Mr Vernall showed living specimens from the ears of a rabbit, and Messrs Cole and W. A, Lewis stated that they had obtained fleas from the hedgehog and European marmot respectively. BIBLIOGRAPHY (No. 47). Beneden (see Van Beneden below). Capelle, /., Extr. from a letter, in which the author states that he had " found worms of the tgenia kind in the liver of sixteen out of eighteen rats," ' Med. Commentaries/ vol. xix, p. 139, 1794; see also ' Trans. Coll. Phys. of Philad./ vol. i, part ii, p. 60, 1793. Chapman, H. C., " Echinorhynchus in Squirrel/' ' Proc. Acad. Philad./ 1874, p. IQ.ColMd, " Note on Ccenurus (from a squirrel)/' ' Proc. Linn. Soc./ May 5, 1864. Idem," On the 320 PARASITES OF ANIMALS occurrence of Tania pectinataiu the Porcupine (Hystrix dorsnfti)," in a letter to Dr. Lawson in the ' Canadian Naturalist and Geologist/ 1862. Idem, ' On T. scrrata,' Ac. (see Bibl. No. 45). Colin, " On the presence of a Nematode Worm in certain Tubercles of the Liver of a Rat/' from ' Rec. de Med. Vet./ in 'Edin. Vet. Rev./ Oct., 1 863. Leuckart, 'Die Blasenband- wiirmer (u. s. w.)/ 1858 (contains numerous details and figs, in ref. to Cysticercus pisiformis and T. serrata, &c.). Marchi, P., 'Mem. della R. Accad. d. Sci. di Torino/ xxv. Peacock, " Remarks on the Liver of a Mouse with Cysts containing Cysticerci," ' Lancet' and ( Trans. Path. Soc./ 1855. Perroncito, E., " Sopra un caso di Coenurus (in the abdominal cavity of a rabbit)/' Giornale Med. Veter./ 1876. Siebold (see Von Siebold, below). Sylvestri, De, " Experiments with C. pisi- formis," ' II. Med. Veterinario/ 1871. Van Beneden (see Bibl. No. 45). Idem, " On Sciurus glacialis and its Parasites/' from 'Bull, de 1'Acad. de Belgique/ in 'Ann. Nat. Hist./ vol. xiii, 1854. Verrall, in ' Proc. Ent. Soc. Lond./ Feb. 15, 1875, p. 3. Von Siebold, ' Ueber die Band- und Blasenwiirmer/ Leipsig, 1854, and Huxley's edit, for Syd. Soc., 1857. Idem, "Experi- ments on the Transformation of the Cystoid Worms into Taenias," from 'Ann. des Sci. Nat./ in 'Ann. Nat. Hist./ vol. x, 1852. Idem, " Helminthology," trans, by Busk and pub. in 'Ray Soc. Rep. on Zool./ 1843-44, p. 446, London, 1847. Idem, "On the Transformation of Cysticercus pisiformis into Tcenia serrata," from ' Zeitsch. f. w. Zool.,' in 'Quart. Journ. Micr. Sci./ 1854. PART VII (EDENTATA). The entozoa of the edentulate mammals are not very numerous. So far as I am aware only one species has been described from the scaly ant-eaters (Manida). This is the small and probably immature ascaris noticed by Whitefield in the walls of the stomach of the badgareit or short-tailed pan- golin (Manis pentadactyla). Amongst the true ant-eaters (Myrmecophagida) a single round worm has also been observed, but not adequately described. I allude to Marcgrav's "find" in the little ant-eater (Myrmecophaga didactyla). I observe that Rudolphi distinctly refers to this edentate as the tamandua. Diesing does the same. The ant-eaters are much infested by a EDENTATA 321 thorn-headed worm (Echinorhynchus echinodiscus) . On the 1st November, 1875, I received from Prof. Flower a jar labelled as follows : " Entozoon found attached to intestine of tamandua ant-eater/' The parasite was procured from the society's gardens on August 12th, 1871. Natterer originally obtained this worm from Myrmecophaga jubata and M. bivittata. Creplin described it from a M. didactyla from Surinam (' Wiegmann's Archiv/ 1849). I presume that M. tam.andua answers to the M. bivittata of Geoffroy, as well as to the tridactyle and tetra- dactyle species of Linnaeus. The parasite in question was a female, measuring exactly 10 inches long, and had its proboscis firmly anchored within the gut. The armadillos (Dasypidas) entertain a variety of nematodes. In 1858 I obtained several examples of Ascaris retusa from the rectum of a poyou or weasel-headed armadillo (Dasypus sexcinctus). The worm was first pro- cured by Natterer from the black armadillo (D. peba), which host also harbors Penta- FlG 60> _ Tdil of the stoma subcylindricum. According to the " finds " of Natterer and the subsequent descriptions by Diesing, the two most common helminths of the Brazilian armadillos are Aspidocephalus scoleciformis and Trichocephalus subspiralis. As regards the sloths (Bradypidtf) it would seem that they are particularly liable to entertain round worms. The Ai (Bradypus tridactylus) is infested by Stron- gylus leptocephalus, Spiroptera gracilis, Sp. anterohelicina, and Sp. br achy stoma; whilst the unau (Cho.loepus didactyius) harbors the last-named species and also Sp. spiralis. All these worms have been described by Molin, and, with the exception of the two first named, were new to science when he wrote his well- known monograph on the genus. They were collected by Natterer. All the species infest either the stomach or intes- tines, with the exception of 8p. spiralis. This singular worm, like the closely allied Sp. helicina, infesting the feet of birds, has the habit of coiling itself amongst the tendons of the digits of the hind limbs more especially. BIBLIOGRAPHY (No. 48). Cobbold, " On some new Forms of Entozoa," 'Linn. Trans./ vol. xxii, p. 365, 1859. Idem," List of Entozoa," &c., ' Proc. Zool. Soo./ March 26, 1861. Idem, " Notes on Entozoa," part iii, ' Proc. Zool. Soc./ Feb. 1, 1876, p. 202. Marcgrav, in his ' Historia rerum nat. Brasil./ 1648, 21 322 PARASITES OF ANIMALS p. 226, and in ' Rudolphi's Synopsis/ p. 186.Molin, " Una Monografia del gen. Spiroptera," 'Aus dem Sitzungsb. d. m.-nat. 01. d. k. Akad. d. Wissensch./ Bd. xxxviii, 1859, s. 911, Wien, I860. Whitefield, in ' Edin. New. Phil. Journ./ edited by Jamieson, 1829, p. 58. PART VIII (RUMINANTIA). In the matter of parasites this order of mammalian animals stands second in importance. An entire volume of the dimen- sions of the present would barely do justice to the subject. Although in the article " Ruminantia " in ' Todd's Cyclo- paedia/ and in my popular treatise on the mammalia, I have described the oxen (Bovida) and sheep (jEgoscerida) as separate families, I shall here speak of their entozoa together ; and, at the same time, I shall introduce occasional reference to the helminths of the antelopes and gnoos (Aniilopida) , also of the giraffes (Camelopardida), the deer tribe (Cervidce), the camels, and the llamas (Camelidce). The parasites of the last family, however, will necessarily stand somewhat apart. Almost all ruminants harbor the liver fluke (Fasciola Ticpa- tica). This worm has been found in every variety of the common ox and zebu (Bos taurus, var. Indicus), in the sheep, goat, and argali (Ovis aries, Gapra hircus, and G. argali) r in the antelopes and gazelle (A. dorcas), in red-deer, roe, and fallow (Gervus claphus, G. caprcoluSj and G. dama), and in the two-humped camel (Gamelus bactrianus). A closely-allied but much larger species of fluke (F. giganted) infests the giraffe (Gamelopardalis). All these animals are more or less liable to suffer from the "rot" which is produced by these flukes. Into the history of the affection the space at my command does not permit me to enter, but as regards the development of the common fluke I believe the following conclusions to be tolerably well founded. I had long entertained the opinion that our common Planorbis plays the role of intermediate bearer, and this view has at length received confirmation. 1. The liver fluke, in its sexually-mature state (Fasc. hepatica), gives rise to the disease commonly called rot; this affection being also locally termed coathe (Dorsetshire, Devon), lies (Corn- wall), and bane (Somersetshire). In France it is known as the Gachexie aqueuse, and more popularly as pourriture. In EUMINANTIA 323 Germany the epidemic disease is called egelseuche, and in a more limited sense either die Fdule or die Leberkrankheit. 2. The rot is especially prevalent during the spring .of the year, at which time the fluke itself and innumerable multitudes of the free eggs are constantly escaping from the alimentary canal of the bearer. The germs are thus ordinarily transferred to open pasture- grounds along with the faeces of the bearer. 3. As it has been shown by dissections that the liver of a single sheep may harbor several hundred flukes, and as, also, a single adult fluke is capable of throwing off several thousand eggs, it is certain that any rot-affected flock is capable of distributing millions of fluke germs. 4. Such flukes as have escaped the host per anum do not exhibit active powers of locomotion. Their slight contractile movements, how- ever, serve the purpose of concealing them in the grass, and probably aid in the further expulsion of eggs, which pass from the oviduct in single file. 5. After the death of the escaped flukes the further dispersion of the eggs is faci- litated by the subsequent decomposition of the parent worm, and also by its dis- integration, partly occasioned by the attacks of insects. It has been calculated that the uterus of a full-grown fluke may contain upwards of forty thousand eggs. 6. By the agency of winds, rains, insects, the feet of cattle, FIG. 61.- Fasciola hepatica. Enlarged. After Blanchard. 324 PARASITES OF ANIMALS dogs, rabbits, and other animals, as well as by man himself, the freed ova are dispersed and carried to considerable distances ; and thus it is that a considerable proportion of them ultimately find their way into ponds, ditches, canals, pools of all kinds, lakes, and running streams. 7. At the time of their expulsion the eggs exhibit a finely segmented condition of the yolk. The egg-contents continue to develop whilst outside 'the parent's body, the granular matrix finally becoming transformed into a ciliated embryo, which when set free follows the habit of infusorial animalcules in general by swimming rapidly in the water. The escape of the embryo is effected at the anterior pole of the egg-shell, which is furnished with a lid that opens in consequence of the action of prolonged immersion, aided by the vigorous movements of the contained embryo. 8. The ciliated, free-swimming embryo, at the time of its birth, exhibits the figure of an inverted cone, its anterior extre- mity, which is broad and somewhat flattened, supporting a central proboscis-like papilla. A small pigment spot placed dorsally, and having the form of a cross, is supposed to be a rudimentary organ of vision. After the lapse of a few days the cilia fall off, the embryo then assuming the character of creeping larvae (planulae). 9. Notwithstanding its abridged locomotive powers the non- ciliated larvae sooner or later gain access to the body of an intermediary bearer, within or upon whose tissues it becomes transformed into a kind of sac or sporocyst. In this condition the larva is capable of developing, agamogenetically, other larvae in its interior. The sporocysts are highly organised, forming redice. According to Willemoes-Suhm, the redia of Fasciola hepatica lives on the body of Planorbis marginata. This organised nurse, which is about a line in length, is the Cercaria cystophora of Wagener. The progeny of this redia consists of armed Cercariae, which after a time quit the nurse to pass an independent existence in the water. 10. In the cases of some species of fluke there is reason to believe that before the Cercarice gain access to their final or definitive host they re-enter the bodies of the mollusks. This they accomplish by means of a boring apparatus, and having previously cast off their tails they encyst themselves beneath the surface of the skin. In this new situation they develop into the so-called pupa, which is at length passively transferred KUMINANTIA 325 with the fodder, or drink, to the digestive organs of the host. In the case of Fasc. hepatica, as probably obtains also with many other flukes, I think there can be no doubt that the Cercarige pass directly into the bodies of ruminating animals. The cir- cumstance that flukes of this species have been found beneath the human skin shows how considerable are the boring powers of the armed Cercarise. In regard to the possibilities of fluke development, that will be best understood by glancing at the constitution of the zoolo- gical individual. The sum total of the products of a single germ may be tabulated as follows : Zoological individual (Fasciola hepatica). a. Ovum in all stages. "1 ,,. , ee .. , ,..,..*. -u f First "biotome." b. Ciliated free-swimming embryo, J c. Nurse, germ-sac, sporocyst (redia),} Second "biotoine." d. Active, migrating, tailed larva (cercaria) ,~\ ^i e. Encysted, resting larva (pupa), > (( biot ^ me f. Sexually-mature fluke (fasciola). J This is a fair representation of the life-phases of the fluke. The life-phases are rarely less numerous or complicated than here indicated, but Pagenstecher's researches tend to prove that under certain climatal conditions the number of larval forms may vary considerably. In other words, the fluke individual does not comprise any definite number of " zooids," although the kinds of zooids are limited. I recognise three (C biotomes." The first includes ,only one temporary, independent life-phase, this is the ciliated animalcule, which I call a " protozooid." The second "biotome" may comprise only a solitary simple sporocyst or germ- sac (deuterozooid), but an almost indefinite multiplication of new and independent germ-sacs, as well as other more highly organised "nurse formations," may also be developed from the primary sporocyst (secondary and tertiary "deuterozooid"). The third " biotome " embraces a large but variable number of " tritozooids " (cercaria), an equal number, whatever that may be, of " tetartozooids " (pupae), and, there- fore, also, a similar number of " pemptozooids " (flukes). Practically, other curious results arise out of the foregoing con- siderations. For example, a single sheep may harbor 1000 flukes. Each fluke will develop 10,000 to 40,000 eggs. Each egg may give rise to 370 zooids. It thus appears that, if all the conditions were favorable, a single fluke might originate between 326 PARASITES OF ANIMALS three and four millions of individualised life-forms, whilst the solitary sheep itself would, under the same circumstances, be the means of causing the production of at least 3,000,000,000 fluke zooids ! Happily, no such results as this can possibly occur in nature, since interfering agencies reduce the favorable conditions. However, the balance of parasitic forms from all sources is usually sufficient to destroy thousands of sheep annually. The virulence of rot-epizooty is entirely due to the presence of con- ditions favoring the development of fluke larvae. As regards the injurious action of this parasite on animals, it is well known that in particular years, in England alone, hundreds, and even thousands, of sheep have been destroyed in a single season. A writer in the ' Edinburgh Veterinary Review ' for 1861 states that in the season of 1830-31 the estimated deaths of sheep from rot was between one and two millions. This would, of course, represent a money loss of something like four million pounds sterling. As affording additional striking instances of the disastrous effects of rot, I may cite the statements of Davaine. Thus : " In the neighbourhood of Aries alone, during the year 1812, no less than 300,000 sheep perished, and at Nimes and Montpellier 90,000. In the inner departments, during the epidemic of the years 1853-54, many cattle-breeders lost a fourth, a third, and even three fourths of their flocks." In like manner our English authority, Prof. Simonds, fur- nished a variety of painful cases. Thus, on the estate of Mr Cramp, of the Isle of Thanet, the rot epidemic of 1824 "swept away 3000 worth of his sheep in less than three months, com- pelling him to give up his farm." Scores of cases are on record where our English farmers have individually lost three, four, five, six, seven, and even eight hundred sheep in a single season ; and many agriculturists have thus become completely ruined. Remarkable periodic outbreaks of this disease are recorded by Simonds as occurring in England in the successive years of 1809, '16, '24, '30, '53, and '60; whilst, for France, Davaine mentions 1809, '12/16, '17, '20, '29, '30, '53, and '54, as the most remark- able years. It would be interesting to know how far these out- breaks tally with the similar outbreaks which have occurred in Holland, Germany, and other European districts. The disease was prevalent during four separate years in France and England at one and the same time. This, indeed, is no more than we would naturally expect, considering that the extent of the RUMINANTIA 327 development of the larval forms must, in a great measure, be dependent upon atmospheric conditions. A warm and moist season would alike prove beneficial to the development of the larvae and their intermediate molluscan hosts. Their numbers would also multiply enormously; for, as already remarked, the degree of non- sexual production of trematode larvae within their sporocysts is materially affected by climatic changes. On the other hand, a fine, dry, open season will tend to check the growth and wanderings of the larvae, and thus render the flocks comparatively secure. Considerations like these sufficiently explain many of the crude theories which were early propagated concerning the causes of this disease, and in particular, the very generally pre- valent notion that water, and water alone, was the true source of the disease. Intelligent cattle-breeders and agriculturists have all along observed that the rot was particularly virulent after long-continued wet weather, and more especially so when there had been a succession of wet seasons. They have likewise noticed that flocks grazing in low pastures and marshy districts were much more liable to invasion than sheep which pastured on higher and drier grounds, but noteworthy exceptions occurred in the case of flocks feeding in the salt-water marshes of our eastern shores. The latter circumstance appears to have suggested the common practice of mixing salt with the food of sheep and cattle, both as a preventive and curative agent ; and there can be little doubt that this remedy has alwaysbeen attended with more or less satisfactory results. The intelligible explana- tion of the good effected by this mode of treatment we shall find to be intimately associated with a correct understanding of the genetic relations of the entozoon, for it is certain that the larvae of Fasciola hepatica exist in the bodies of fresh-water snails. As already hinted from Willemoes-Suhm's observations, it is not improbable that the larvae are confined to gasteropod mollusks belonging to the genus Planorbis. The symptoms produced by rot are very striking. When the disease has far advanced it is easy to know a rotten sheep, not only by its very look, but still more convincingly, as I have myself tested, by slightly pressing the hand over the region of the loins. In this region the diseased animal is particularly weak, and the pressure thus applied instantly causes it to wince. At the same time the hand feels a peculiar sensation very unlike that communicated by the spine of a sound animal. In bad 328 PARASITES OF ANIMALS cases the back becomes hollow, and there is a corresponding pendulous condition of the abdomen. The spinal columns ulti- mately stick out prominently, forming the so-called "razor- back." As Professor Simonds has well observed, in an earlier stage of the disease, " an examination of the eye will readily assist in determining the nature of the malady. If the lids are everted it will be found that the vessels of the conjunctiva are turgid with pale or yellowish colored blood, the whole part presenting a peculiar moist or watery appearance. Later on, the same vessels become blanched and scarcely recognisable." The skin also becomes harsh and dry, losing its natural tint, and the wool is at length rendered brittle, either becoming very easily detached or falling off spontaneously. The first thing noticeable in dissecting a rotten sheep is the wasted and watery condition of all the tissues. There is a total absence of that firm, fresh, carneous look which so dis- tinctively characterises the flesh in a state of health. Not only is the. rigidity and firm consistency of the muscles altogether wanting, but these structures have lost that deep reddish color which normally exists. When the abdominal cavity is opened a more or less abundant, clear, limpid, or yellowish fluid will make its escape, and the entire visceral contents will, at the same time, display a remarkably blanched aspect. These pathological changes are also shared by the important organ especially affected, namely, the liver. This gland has lost its general plumpness, smoothness, and rich, reddish-brown color, and has become irregularly knotted and uneven both at the surface and the margins, its coloring being either a dirty chocolate brown, more or less strongly pronounced at different parts, or it has a peculiar yellowish tint, which in places is very pale and conspicuous. To the feel it is hard and brawny, and when incised by the scalpel, yields a tough and, in places, a very gritty sensation. On opening the gall-ducts a dark, thick, grumous, biliary secretion oozes slowly out, together with several distomes, which, if not dead, slowly curve upon them- selves, and roll up like a slip of heated parchment. On further slitting open the biliary passages, they are found distended irregularly at various points, and in certain situations many flukes are massed together, having caused the ducts to form large sacs, in which the parasites are snugly ensconced. The walls of the ducts are also much thickened in places, and hard- ened by a deposit of coarse calcareous grains on their inner RUMINANTIA 329 surface. Mr Simonds says, that the " coats of the ductus hepaticuSj as also of the ductus communis choledicus, are not unfrequently so thick as to be upwards of ten times their normal substance, and, likewise, so hard as to approach the nature of cartilage." Respecting their numbers, the greatest variation exists. The presence of a few flukes in the liver is totally insufficient to cause death ; consequently, when a sheep dies from rot, or is killed at a time when the disease has seriously impoverished the animal, then we are sure to find the organ occupied by many dozen, many score, or even several hundred flukes. Thus from a single liver Bidloo obtained 800, Leuwenhoeck about 900, and Dupuy upwards of 1000 speci- mens. Even the occurrence of large numbers only destroys the animal by slow degrees, and, possibly, without producing much physical suffering, excepting, perhaps, in the later stages. Associated with the above-described appearances, one also not unfrequently finds a few flukes in the intestinal canal, whilst a still more interesting pathological feature is seen in the fact that the bile contained in the liver ducts is loaded with flukes' eggs. In some cases there cannot be less than tens or even hundreds of thousands. Not a few may also be found in the in- testinal canal and in the excrement about to be voided. Occasion- ally dead specimens become surrounded by inspissated bile, and gritty particles deposited in the liver ducts, thus forming the nuclei of gall-stones. Mr Simonds mentions a remarkable instance, " where the concretion was as large as an ordinary hen's egg, and when broken up was found to contain about a dozen dead flukes. It was lying in a pouch-like cavity of one of the biliary ducts/' In respect of treatment we all know that "prevention is better than cure." Moisture being essential to the growth and development of the fluke-larvae, it is clear that sheep cannot be infected so long as they remain on high and dry grounds, and even in low pastures they can scarcely take the disease so long as they are folded, and fed on hay, turnips, and fodder pro- cured from drier situations. When once the malady has become fairly developed, internal remedies are of little avail, at least, in view of producing a thorough cure. Palliative treat- ment may undoubtedly do good, especially in cases where the disease is not very strongly pronounced. The most important thing is the transference of the rot-affected animals to dry ground and good shelter, supplying them, at the same time, 330 PARASITES OF ANIMALS with a liberal quantity of manger food, such as beans, peas, and other leguminous seeds. The fodder, of whatever kind, should be frequently changed, and many other hygienic measures adopted, all tending to promote the appetite and general health of the animal. An admixture of salines is a matter of essential importance, especially in cases where the disease is not far advanced. The beneficial effect of salt is one of those few points on which nearly all parties are agreed, and its preserva- tive influence in the case of sheep fed upon salt-water marsh- land has been previously explained. In regard, however, to the legion of remedies which have from time to time been pro- posed, all I need here say is, that most of them when fairly tested have been found to fail ignominiously. Every year we hear of the adoption, often with enthusiasm, of new so-called specifics, or of ancient medicines whose employment had long fallen into disuse. T.hus, for example, in the April number of the ' Journal des Veterinaires du Midi ' for 1 860, we find M. Raynaud strongly recommending soot, in doses of from one to three spoonfuls, to be followed up by the administration of a grain of lupin for tonic purposes. In like manner, we received from France wonderful accounts of the medicinal virtues of a certain foetid oleaginous compound, the value of which was put to a fair test by our distinguished veterinarian, Professor Simonds. Having with infinite care and trouble undertaken a series of experiments with the remedy in question, Mr Simonds writes in the ' Scottish Farmer and Horticulturist ' to the effect that, as a result of his inquiries, he fears " we must conclude that this supposed cure of rot in sheep has proved quite ineffective for good." The last new " cure " announced is by Mr Robert Fletcher (' Journ. Nat. Agric. Soc. of Victoria/ Dec., 1878). The examination of rotten sheep is not altogether free from danger. Professor Simonds tells us that in August, 1854, " a person of intemperate habits, following the occupa- tion of a country butcher, was employed in skinning and dressing a number of rotten sheep on the premises of a farmer in the county of Norfolk. The sheep were necessarily opened when warm, and while he was so engaged he complained greatly of the sickening smell. The same evening he was attacked with choleraic disease, and two days afterwards was a corpse." This case is highly instructive and, when taken in connection with the well-known fact that animals affected with the disease putrefy very rapidly, clearly points to the neces- EUMINANTIA 331 sity of removing slaughter-houses far away from densely popu- lated localities. Notwithstanding the above statement, there is little or no danger to be apprehended from the consumption of the flesh of rot-affected animals. On this vexed question we have the strong testimony of the late Dr Rowe, of Australia, who, after leaving the medical profession, became a large and successful stockowner, and devoted himself especially to this question. Dr Howe, writing from the Goulburn district, said : The mere presence of flukes in the viscera of an animal is no proof that it is unfit for human food. For inspectors of slaughter-houses to adopt such a test of wholesome food would be the greatest mistake. It would afford no protection to the public against unhealthy food, would increase the price of animals, and be ruinous to our farmers and graziers. If the consumption of flukey beef and mutton were prejudicial to the health . of man, there would be very few people alive in this part of the colony; for, to my certain knowledge, they have had no other animal food to live upon for the last twenty-five years, yet for physical ability I believe they may be favorably compared with the inhabitants of any other part of Australia." Speaking of his own experiences, Dr Howe avers that he found the common liver fluke in sheep, cattle, goats, opossums, kangaroos, geese, ducks, and other creatures, but he had never encountered it in men, dogs, or pigs. On the whole I think we may agree with Dr Rowe, in regarding the consumption of the flesh of rot- affected animals as free from danger provided only the meat, be well or even moderately well cooked. It must be borne in mind, however, that an essential objection to its consumption lies in the fact that the watery and otherwise chemically deteriorated flesh is comparatively innutritious. It must also be noted that the meat-supply from fluke-affected animals, as usually sold in the markets, is chiefly derived from animals which have only entered the early stage of the disorder, that is, long before the watery and wasted condition of the muscles has fairly set in. Respecting the other trematodes I have to observe that Distoma, lanceolatum not only infests the liver ducts of cattle and sheep, but also the deer tribe. Its larvae are likewise supposed to reside in Planorbis marginatus. Still more common and widespread amongst ruminants is the Amphistoma conicum, occupying the paunch. It has been found in the ox, sheep, 332 PARASITES OF ANIMALS musk-ox, elk, roe, fallow, red-deer, goat, and dorcas-antelope ; also in Cervus campestris, G. nambi, G. rufus, and C. simplicornis. Prof. Garrod has also recently shown me examples from the sambu deer of India (G. Aristotelis) . Diesing's A. lunatum, infesting Cervus dichotomies, is inadmissible. Two other species of Amphistome (A. explanatum, A. crumeniferum) are said to infest the zebu ; and I have described another (A. tuberculatum) from the intestines of Indian cattle. An aberrant amphis- tomatoid entozoon (Gyrocotyle rugosa) has been found in a Cape antelope (A. pygarga). Of more interest, however, is the cir- cumstance that Dr Sonsino has discovered a species of Bilharzia (B. bovis) in Egyptian cattle and in sheep. The eggs of this species are distinctive, being fusiform and narrowed towards either pole. Comparatively few tapeworms are found in ruminants. Cattle are infested by Tania expansa and T. denticulata, the former of these two species being also more or less prevalent in sheep, antelopes, and deer. Other alleged species (Ttenia fimbriata and T. caprce) appear to me more than doubtful. Unquestion- ably the common Tania expansa is capable of giving rise to severe epizooty among lambs. The privately communicated evidence of Professors Brown and Axe, and published evidence supplied by Messrs Cox and Robertson on this head, are con- clusive. Mr George Rugg has also (in a letter to Prof. Simonds, dated Dec. 4th, 1878) communicated the particulars of an out- break in which " large numbers of lambs perished rapidly" from tapeworms in the intestines, the parasites varying from one to five or six feet in length. This tapeworm (T. expansa) is also very prevalent in Germany. Ruminants, however, both at home and abroad, suffer much more severely from bladder-worms. Of these, Echinococcus veterinorum, Gysticercus tenuicollis, and Coenurus cerebralis, are not only shared alike by all varieties of cattle, sheep, and goats, but they also infest the deer tribe, antelopes, the giraffe, and even camels. In 1859 I obtained the slender-necked hydatid from a spring-bok (Gazella) . Besides these larval cestodes, cattle are very liable to harbor measles (Gysticercus bovis), whilst sheep also entertain an armed Cysti- cercus (C. ovis). I cannot again dwell at any length upon the source of these immature helminths, but I may remark upon the extreme frequency of measles in Indian cattle. This is explained by the careless habits of the people. They not only consume veal and beef in an imperfectly cooked state, but when BUMINANTIA 333 suffering from tapeworm no precautions are taken to prevent cattle from having access to the expelled proglottides of Ttenia medio- canellata. The subject has already been dealt with in the first part of this work, and also in my ' Manual/ quoted in the bibliography. The mutton measle is described under the heading of T&nia tenella. In like manner I must refer to the ' Manual' for a detailed account of the gid hydatid (Coenurus cerebralis}. How many kinds of Coenuri exist it is impossible to say, but I am of opinion that the various polycephalous bladder-worms found by Rose, Baillet, and Alston in rabbits, by myself in a lemur and in a squirrel, and by Engelmeyer in the liver of a cat, are referable to tape- worms specifically distinct from the Taenia coenurus of the dog. It was in 1833 that Mr C. B. Rose, formerly of Swaffham, Norfolk, discovered an undoubted example of polycephalous hydatid in the rabbit, the parasite in question bearing a very close resemblance to Gcenurus cerebralis. As the accuracy of Rose's determination respecting the characters of the hydatid has been called in question, I again invite attention to the original description as recorded in the ' London Medical Gazette ' for November 9th, 1833. At page 206, vol. xiii, of that perio- dical, after describing the common Ccenurus cerebralis of the sheep, Rose writes : te This (i.e. C. cerebralis) is the only species of Coenurus noticed by authors, but I have met with another. It infests the rabbit, and I have found it situated between the muscles of the loins. It is also met with in the neck and back. This hydatid grows rapidly, and multiplies prodigiously, and being seated near the surface it soon projects, and sometimes forms a tumour of considerable magnitude. When the warrener meets with a rabbit thus affected, he punc- tures the tumour, squeezes out the fluid, and sends the animal to market with its brethren. I possess a specimen of this species in a pregnant state. The earliest visible state of gesta- tion is a minute spot, more transparent than the surrounding coats of the parent; this enlarges till it projects from the parietes of the maternal vesicle. It continues to enlarge until it becomes a perfect hydatid, attached by a slender peduncle only ; even whilst small, other young are seen sprouting from it, and so on in a series of three or four. My specimen exhibits them in every stage of growth, from a minute point to a vesicle the size of a hen's egg. As I can see no difference in structure between this hydatid and the last-mentioned (i.e. Coenurus cerebralis), I am unwilling to consider it a different 334 PARASITES OF ANIMALS species, for surely a varying locality ought not to constitute a specific character." The observations of Rose did not escape the well-known Dutch author, Numan. In a foot-note to his memoir, entitled " Over den veelkop-blaasworm der Hersenen," he makes the following observations : " Rose observes that he has found Ccenurus in bladdery rabbits (blaaszieke konijnen) in the skin, and in the cellular tissues of the trunk and extremities. The veterinary surgeon, Engelmeyer, of Burgau, says he has also found the Ccenurus (Veelkop) in the liver of a cat (' Thierarzt- liche Wochenschrift van 1850/ s. 192). These observations differ thus far from those of other writers, according to whom the Ccenurus is only found in the brain and spinal marrow. However, it is not impossible in particular cases that some parasites may have strayed from their ordinary dwelling-places." Numan seems to have been not a little puzzled to account for these discrepancies, and he was altogether undecided regarding the mode of propagation of Coenuri and Cysticerci. This will be gathered from the following passage, which I quote in the original : " Ik moet het onbeslist laten, of de grondbeginsels, waaruit de wormen uit de blaas ontspruiten, als wezenlijke of als zooge- naamde kiemen (gemma) zijn te houden, waaromtrent de gevoe- lens der vooruamste Natuuronderzoekers, die zich met de nasporing der blaaswormen hebben onledig gehouden, nog uiteenloopen. Gulliver, door Rose (a. p. pag. 231) aangehaald, houdt ze voor eijeren, in den Cysticercus tenuicollis, en Goodsir, mede aldaar genoemd, spreekt ook van ova bij den Ccenurus cerebralis ; doch de laatstgenoemde en Busk houden ze voor gemma. Hier wordt voots gewezen op Owen en de meeste onderzoekers van den tegenwoordigen tijd, die het daarvoor houden, dat alle hydatiden zich alleen door gemma reproduceren. Rose merkt voorts aan, dat, hetzij men de geboorte dezer inge- wands wormen toekenne aan eijeren of kiemen (gemma), dit om het even is, wat hunne verspreiding (dissemination) betreft, daar zij ingesloten zijn, waardoor de wijze, hoe zij naar buiten komen en verspried worden, tot dusver een gesloten boek is." The idea of Numan that these are strayed forms of Ccenurus cerebralis is not convincing. It must not be forgotten, however, as Leuckart and Numan have both reminded us, that Eichler discovered an hydatid about the size of a goose egg in the sub- cutaneous tissue of a sheep. This bladder-worm supported EUMINANTIA 335 nearly two thousand heads. In regard to true hydatids or acephalocysts in ruminants, on which subject I have already dwelt at much length, I may again observe that the Hunterian Museum contains some remarkable examples. In 1854 I obtained Cysticerci from a giraffe, and I have reason to believe that similar bladder-worms infest antelopes and deer. The nematodes of the ruminants are both numerous in, and destructive to, their bearers, those infesting the lungs being productive of a parasitic bronchitis termed husk or hoose. In cattle the lung- worm (Strongylus micrurus) is particularly fatal to calves, whilst S. filaria attacks sheep, and especially lambs. A larger but less common lung strongyle (S. rufescens) is some- times found associated with the latter. In 1875 I conducted experiments with the view of finding the intermediate hosts of 8. micrurus, and I arrived at the conclusion that the larvae of this parasite are passively transferred to the digestive organs of earth-worms. The growth and metamorphoses which I witnessed in strongyloid larvae taken from earth-worms (into which I had previously introduced embryos) were remarkably rapid, and accompanied by ecdysis. The facts were as follows. About the middle of October, 1875, I received from Messrs Farrow, of Durham, a fresh and characteristic specimen of diseased lungs, in which the bronchi were swarming with Filariae. In reference to the case itself, Mr George Farrow afterwards informed me by letter that the calf was one of a herd of seven, whose ages respectively varied from four to six months. At the time of his writing (October 20th) the remaining six animals were progressing favorably towards recovery a result which Mr Farrow attributes to the employment of inhalations of tur- pentine and savin, combined with the internal adminstration of tonics, In regard to this plan of treatment, and in reference to the source of infection, he adds : " I should have preferred trying the inhalations of chlorine gas, but as the patients were so very young and in poor condition, I deemed it advisable to try a milder course of treatment. " The history of the case is brief. The cattle are on a very dry and well-drained farm, but during the summer there was a great scarcity of water, and they were supplied from a stagnant pool which eventually became dry. This, in my opinion, is where the disease originated." Mr George Farrow's opinion is probably correct, being in harmony with the most recent results of scientific research as 336 PARASITES OF ANIMALS made known more particularly by Leuckart. But the facts thus conveyed do not explain the whole truth ; or, rather, they convey it only in a very incomplete manner. Professor Leuckart's experiments were made with several species such as Strongylus armatus of the horse, S. rufescens, 8. hypostomus, and S.filaria of the sheep, and 8. commutatus of the hare. Still, as regards the strongyles, partial as the results have thus far appeared, there cannot be a doubt that his successes with several allied nematode species form a key by which we may yet unlock and expose to view the entire life-history of that specially obnoxious form under consideration, namely, Strongylus micrurus. To summarise the whole matter in a few words, Leuckart supposes that all these strongyloids require a change of hosts before they can take up their final abode in the sexually-mature state. This he infers especially because their respective embryos display characters very similar to those exhibited by Olulanus. He believes that either small mollusks or insects and their larvae play the role of intermediary bearer. His experiments with the embryos of Strongylus filaria prove that these larvae can be kept alive for several weeks in moist earth, and that whilst so conditioned they undergo a first change of skin within a period varying from eight to fourteen days. Experiments on sheep, made with these moulting larvae, led only to negative results. Unless the following facts be accepted, the scientific position remains pretty much where Leuckart left it. On the 22nd of October, 1875, at 1 p.m., I placed the entire egg-contents of the- uterus of a Strongylus micrurus on a glass slide hollowed out in the centre. Probably something like ten thousand ova were thus brought under observation, yet only three were noticed as freed from their shells, probably as the result of accidental rupture. Two of these displayed lively movements. In round numbers the ova gave a measurement of ago of an inch in length by ^ of an inch in breadth, whilst the free embryos measured about ^ of an inch long, and less than o of an inch in thickness. The integument of the embryo displayed neither markings of any kind nor any double contour. The contents of the worm were gnanular throughout, these granules being crowded in the centre of the body, but scarcely visible towards the head and tail, where for a considerable space (fully T^") the worm was perfectly transparent. No trace of any sexual organs or their outlets was visible. An examina- tion of numerous eggs and free embryos obtained from near the EUMINANTIA 337 primary bronchial bifurcations (of Mr Farrow's specimen) yielded the same microscopic results, the only thing worthy of remark being that the embryos from the mucus seemed much more lively than those which, as I supposed, had accidentally escaped their shells. At 1.30 p.m. I placed some free embryos in two watch-glasses, one containing water and the other saliva, and placed them before the fire. Being called away professionally I found on my return at 3 p.m. that evaporation to dryness had occurred in the interval. All my attempts to resuscitate the embryos by moisture proved unavailing, a result which, though negative, proves how little capable these embryonic creatures are of enduring desiccation. If these facts be confirmed, their prac- tical significance is not without value in relation to the choice of dry pasturage grounds for the rearing of young cattle. I may add that whilst half an hour's immersion of the dried embryos failed to restore any sign of life, the previous warmth and moisture had caused many more embryos to escape their shells during the time they were placed before the fire. At 4 p.m. I passed some very rich mould through muslin. Some of this finely sifted earth I placed in a watch-glass, adding a little water to moisten it, and also numerous eggs and free embryos. In a wine-glass and also in a small jar I placed some coarse earth with water added to make thin mud, and to both of these I added, not only eggs and embryos, but also portions of the reproductive organs of the adult female worms. On the 23rd of October, at 2 p.m., I examined the contents of these vessels. All the embryos in the vessels containing the coarse earth were dead, but several were found alive in the watch-glass containing the fine moist mould. Structually these latter had undergone no perceptible change beyond a somewhat closer aggregation of the somatic granules. Although the embryos in the coarse wet mud had perished, the eggs with unhatched embryos appeared to have retained their vitality. Of this fact, indeed, I subsequently obtained abundant proof ; and I also satisfied myself that the death of the embryos had not resulted either from the coarseness of the earth or from excessive moisture, but from the presence of numerous shreds of the uterine tubes which I had somewhat carelessly added to the vessels. Previous experiments, con- ducted many years back, had indeed taught me that few if any 22 338 PARASITES OF ANIMALS nematoid larvae can resist the fatal action of putrid matter, however slight the putrescence. Having removed the offending shreds, I next placed a quan- tity of living ova together in the earthenware jar, and allowed the earth-contents to become much drier by evaporation before the fire. I also left others in a watch-glass, which was placed under a bell-jar enclosing several ferns. On the 25th of October I removed particles of the moist earth, altogether weighing about two grains, and, on submitting them to microscopic examination, had the satisfaction to observe about a dozen living embryos, some of which exhibited very lively movements. There was not the slightest indication of putridity ; nevertheless, I noticed several shreds of the adult worms whose presence had been accidentally overlooked, and, curiously enough, all the embryos subsequently removed from the immediate neighbourhood of these decomposing shreds of tissue were almost motionless and apparently in a moribund condition. On examining the contents of the watch-glass placed under the fern shade, I noticed several points of interest. First of all the earth contained strongyle embryos, such as I had seen before. Secondly, the surface of the mould was being traversed by three or four briskly- moving Thysanurida, hunting about with all that restless activity which Sir John Lubbock has so welL described. Thirdly, in marked contrast to the behaviour of these I noticed several slow-moving Acarida, apparently also employed in searching for food. And lastly, while thus engaged, the surface of the mould in the centre of the deep watch-glass was suddenly upheaved, by which I was at once made aware of the presence of another most welcome and unexpected intruder. In short, an earth-worm had crept from the dry mould in which the ferns were growing, and had taken up its temporary abode in the soft moist experimental-earth contained in the watch-glass. When contracted, this Lumbricus terrestris was barely an inch in length. On placing it under the half-inch objective glass, I noticed a single embryonic strongyle adhering to the skin, but not firmly, and evidently only in an accidental way, so to speak. It was clear to me that it possessed neither the intention nor the power to penetrate the chitinous integument of the earth-worm. Having in the next place removed the Lumbricus with a pair of forceps, and having washed it under a current of water, I snipped off the lower end of the body, and allowed some of the intestinal contents to escape on a clean glass slide for separate EUMINANTIA 339 microscopic examination. Immediately, to my satisfaction, I found that the fsecal contents displayed a large quantity of my strongyle ova, enclosing still living embryos, and in addition several free embryos presenting characters which declared that they were from the same source. Clearly they had been ingested by the earth-worm along with its ordinary food. One or two of the embryos were conspicuously larger than their fellows, but the structural changes they had under- gone were not so marked as to lead me for a single moment to associate them with any of the various sexually- mature worms which have been described as normally infesting the earth-worm. I had no doubt whatever that such slight structural changes as were now discernible had resulted from growth and develop- ment consequent upon this accidental admission into the body of the intermediate bearer which might or might not prove to be its legitimate territory. It will be seen that subsequent observations tended to affirm the truth of this view. I made a careful examination of one of these larvae, whose active move- ments were such as to render the process exceedingly tedious. The earth-worm itself (or rather its unequal halves) was placed in a fresh watch-glass containing ordinary mould. The larvae or embryos obtained from the earth-worm now measured about of an inch in length, their heads exhibiting a short and simple chitinous buccal tube, whilst their tails were somewhat more pointed and bent upward. The somatic granules were more crowded, rendering the position of the intestinal tract more marked, though, as yet, the differentiation gave no indi- cation of the formation of a distinct intestinal wall. There was no perceptible increase of thickness of the body of the embryos. The results thus far naturally encouraged me to procure some fresh earth-worms for experimental purposes. On the 26th of October I found that the halves of the earth- worm were alive, and I left them undisturbed in rather dry mould, freshly added. To a watch-glass containing newly sifted earth and embryos I added a fresh garden-worm, which was rather sluggish from the cold ; and in the original jar I placed another smaller and very active earth-worm obtained the same morning. Finding the soil in the jar congenial, this lumbricus soon buried itself. Another and larger earth-worm subsequently added refused to follow this example. It was therefore removed from the jar. Believing the fine and arti- 340 PARASITES OF ANIMALS ficially prepared soil to be still much too moist, I caused further evaporation ; and I afterwards found that the thicker the mud the more suitable it proved as a residence for embryonic nema- todes and earth-worms alike. On the 27th I found the small earth-worms in the jar bur- rowing freely and throwing up faecal casts. From one of my watch-glasses the worm had escaped, its place being occupied in the meantime by an actively crawling Julus. I put a second Julus, obtained from the mould in the fern jar, to form a com- panion (in view of other experiments), and I also added a fresh earth-worm, covering all by another inverted watch-glass, which I thought would prevent their escape. In the next place I examined the halves of my original experimental earth-worm. They were scarcely capable of motion, but retained a certain amount of vitality. The tail was the more active half, and unfortunately it was soon after- wards lost. Carefully washing the superior half, and transfer- ring its contents to a glass slide, I immediately detected under the microscope a large number of embryos. They were in a state of marked activity, the largest having increased to about 35" of an inch in length, whilst their structure had become cor- respondingly advanced. Here, again, there was no room for doubt as to their source, especially as they individually dis- played different degrees of organisation, all answering to one and the same embryonal type. I now observed a distinct oesophagus, the rest of the intestinal tract being still more con- spicuous than heretofore, though, as yet, no true cells marked the limitation of the stomach and chylous intestine. After an hour's immersion in cold water some of the larva) became much less active, whilst others were motionless, so that I feared all were about to perish. In the hope of keeping a few of them alive I now added to the slide some finely sifted grains of mould, placing the slide under a small bell jar which protected some of my ferns. The remains of the moribund earth-worm were also covered with mould. Other larvae, derived from the earth-worm, were placed on the moist pinnae of a living fern-frond which supported small drops of water, for by this process I hoped in some mea- sure to imitate the dew which naturally condenses on the grass and fodder of our low-lying fields. At 3.15 p.m. of the same day (27th) I also examined a fresh worm pellet from the jar, and found it to contain living strongyle embryos, which as RUMINANTTA 341 heretofore had not exhibited the slightest advance either in respect of size or structure. At noon on the 28th I again sought for the larger larvae, first of all on the slide covered with fine earth, and afterwards within the remains of the upper half of the original earth-worm. On the slide I could detect none, but within the intestine of the worm there were still two living larvae left, whose characters corresponded precisely with the largest that I had previously obtained from the same source only the day before. They had undergone, however, no further change in structure, and their measurements remained precisely the same. At 12.30 p.m. I snipped off two or three of the terminal fern- fronds on which I had placed a few advanced larvae. On examination under the half-inch objective I immediately de- tected one of the larvae cruising about most actively. On adding a drop of water it soon rushed across the field of the microscope, its movements being thoroughly eel-like. The size of this larva had so much increased that it was now visible to the naked eye, measuring, indeed, as much as ^" of an inch from head to tail. Moreover, its organisation had advanced in a marked degree. Thus, the digestive organs were better defined, and on one side of them there appeared a regularly arranged congeries of cellules, forming the commencement of the reproductive organs. As yet, however, I could not pro- nounce as to the sex. At 1.45 p.m. I again examined a few grains of earth from the jar, when I at once noticed five or six active embryos whose structure failed to show the slightest advance upon that origi- nally described. It was evident that the jar contained thou- sands of them ; and since no ova were found, it became pro- bable that all their embryonic contents had escaped to swell the number of free larvae, leaving their very delicate envelopes to perish. I think I had hit upon the most suitable degree of moisture favorable to this result. In the next place I sought for the earth-worm that had been placed in the infested soil between two watch-glasses. It had escaped. This obliged me to transfer the mould to a rather wide-mouthed and open phial, in which four more fresh lumbrici were placed. I feared the closing of the bottle would be detrimental. Later in the day I selected an earth-worm which had not been exposed to strongyle infection, but which was in a mori- 342 PAKASITES OF ANIMALS bund condition. In the intestine there were several free nematoids and also several psorosperms of the genus Monocystis, so well illustrated by E. Ray Lankester. As to the nematoids, which were filariform, they neither corresponded in size nor structure with my strongyle embryos. At 1 p.m. on the 29th I renewed my examination of the larva removed from the fern-pinnule. It showed a further stage of growth, the male character of the reproductive organs having become apparent. The now tolerably well-formed vas deferens had pushed the chylous intestine on one side, whilst a series of caudal rays, five on either side, supported two narrow membranous wings, which represented the lateral lobes of the hood of the adult strongyle. At 1.30 p.m. I submitted the intestinal contents of four fresh earth-worms removed from my garden to microscopic examina- tion, but no nematoids were found in any one of them. About 2 p.m. I removed another large and active strongyle larva that had been reared on another fern- pinnule. It was of the same size as that previously described, but was in the act of changing its skin. It was then put aside along with the other worm under the glass shade. At 3 p.m. I intended to have examined one or more of the earth-worms placed in the open-mouthed phial, but all had escaped and buried themselves in the fern-mould out of reach. At noon on the 30th I renewed my examination of the two large larvae whose developmental changes I had been instru- mental in producing from the time of their escape from the egg-coverings. I saw no reason to doubt that the sequence of changes thus far noticed referred to the species of parasite under consideration. Both larvse were active, but the moult- ing one had now completed its ecdysis. Its sexual distinctive- ness had become yet more pronounced by the formation of two rather short and stout spicules, the point of the tail dis- playing a very minute awl-shaped projection. The lateral membranes had not visibly increased in size. One of these larvse, the first under observation, now perished from the injuries sustained during inspection. Again, and later in the day, I sought to clear up any doubts that might still suggest themselves respecting the source of these larvae, by once more submitting the intestinal contents of two fresh and uninfected earth-worms to careful scrutiny. In the first worm no parasite could be found, and in the second EUMINANTIA 343 only one minute nematoid ; its organisation, which was sexually incomplete, neither corresponded with my strongyle embryos, nor, so far as I could judge, with Groeze's Ascaris minutissima microscopica (the Anguillula lumbrici of Diesing and others), nor with Dujardin's Dicelis filaria. It was a very long and narrow creature, but I lost it whilst attempting to secure an accurate measurement. I should say it was about ~th of an inch in length, and not more than 7350 th in breadth. I made a rough outline sketch of it. In view of further observations I now placed five more earth-worms in the jar containing strongyle embryos, and I also placed six others in the phial which contained coarser mould, and only a comparatively small number of the original strongyle embryos. The phial was closed with a cork and half buried in the fern-mould of one of my larger Wardian fern-pans. Before this transfer was made I again took an opportunity of ascertaining by microscopic evidence that the embryos lodged in the coarse and fine mould had none of them made the slightest advance in organisation. The worms placed in the jar immediately proceeded to bury themselves. At noon on the 1st of November I sought to get further results from the only large free larva which now remained to me (for the fern-pinnules on which the larvae were originally placed had dried up and no third specimen could be discovered). Structurally the larva presented no advance. It there- fore appeared to me necessary to place it under new con- ditions in view of exciting further progress towards sexual maturity and adult growth. To transfer it to the bron- chus of a living calf would, of course, have been the crucial experiment, but the hopelessness of getting any satis- factory result from this solitary transfer deterred me from the attempt. On a larger scale, with many larvae, a positive issue would of course prove decisive. Accordingly, the only thing I could do, in partial imitation of nature, was to try and induce some further changes by placing the larva in human saliva, kept warm artificially. As a first step I immersed the creature in a little of the secretion added to the glass slide, when it - immediately displayed very lively movements, such as could only be fitly described as frantic. This encouraged me to replace the slide under one of the fern shades without applying any additional heat. I then left it. At 12.30 p.m. I selected three of the eleven worms lodged iu 344 PARASITES OF ANIMALS the infested earth, namely, two from the jar and one from the closed phial, and made a microscopic examination of their respective intestinal contents. In one of the worms from the jar I found several embryos clearly referable to my strongyles, their structure showing scarcely any advance upon that exhi- bited by the embryos in the mould itself. The weather was now excessively cold and the larvaB were motionless ; neverthe- less, the application of warmth showed that they were by no means dead. The faacal matter obtained from the worm that had lived in the phial displayed an immense number of infusoriae (Bacteria) which rushed about rapidly over the field of the microscope. No other signs of life were detected. On the 2nd of November I found my solitary strongyle larva alive, but its movements, though active, were by no means so active as on the previous day. No fresh structural changes had occurred. At noon on the 3rd the larva at first lay almost motionless in the now thick and ropy saliva ; nevertheless, on applying a thin glass cover its movements became tolerably vigorous. During its quiescent state I succeeded in getting a good view of the caudal rays and other imperfectly developed organs, of which I retain figures. Having now satisfied myself that other new conditions were necessary to enable the larva to arrive at sexual maturity, I sought to transfer it to a glass tube filled with fresh saliva. This transfer was a matter of difficulty. After passing the thick ropy saliva into the tube, I examined the slide and found that the larva was gone. I concluded it was in the tube, which, in order to keep the contents warm, I subsequently carried about concealed in my under-clothing during the day and placed in my bed during the night. This increase of temperature, however, caused decomposition of the saliva ; so when next day I diligently sought for my experimental nematode it was no- where to be found. Thus terminated my observations on the first set of embryos, which had enjoyed their temporary sojourn in the intestinal tract of the earth-worm, and which had certainly afterwards undergone a series of marked structural and mor- phological changes, accompanied with ecdysis. The weather had now been for several days exceedingly cold, but on the 4th a favorable change set in, which led me to hope that I might be able to verify the facts above recorded. Accordingly, as a new point of departure, I re-examined the RUMINANTIA 345 fine mould, and at once found my embryos in a high state of activity. The mould, however, appearing too moist for the earth-worms, I permitted further evaporation before closing the jar with a glass cover. Four days subsequently I examined the intestinal contents of two of the earth-worms. In one of these, an inch in length, no parasite of any kind could be de- tected ; but in the other, which was beyond three inches in length, there were numerous Opaline besides several strongyle embryos, the latter presenting characters not visibly in advance of those still living in the mould. All of them were motionless, as if they had not got over the shock produced by previous cold. Moreover, the weather had again become cold, and thus, when I again inspected my experimental embryos living in the jar, I also found them motionless, so different from their behaviour on the 4th. However, since a further result with the earth-worm embryos appeared possible, I placed some of the faecal matter, already ascertained to contain a few of them, on the fronds of a thoroughly moist and dew-covered Asplenium bulbiferum. This plant was in a fern-pan which had the advan- tage of considerable fire- warmth during the day. When, how- ever, on the 15th of November, I examined the fgecal earth removed from several of the pinnules, I failed to find any of the embryos. Possibly they had wandered, for the entire frond was covered with dew-drops, which was not the case with the fern that I had previously experimented on with such satis- factory results. At all events, whether they had wandered or had perished, their apparent absence in no way affects my pre- vious record ; and the more so since only a few had been observed in the fa3cal matter. The smallness of the number found in the earth-worm was also readily accounted for. Thus, when at 1.30 p.m. on the 15th I made a diligent search for embryos in several grains of the fine mould, not a single young strongyle could be detected. Possibly the frost of the previous night had killed them. The earth-worms were still alive and in good condition. In conclusion, I may observe that every experimenter with helminths is well aware how unfavorable the winter season is for this kind of research. If a repetition of this inquiry in the spring or summer should confirm these results, it will prove a clear and substantial addition to our knowledge of the develop- ment of the strongyles. Meanwhile, I think that the data above given render it highly probable that the larvae of the noose-producing strongyle (8. micrurus) are passively trans- 346 PARASITES OF ANIMALS f erred to the bodies of setigerous annelids, which are thus called upon to act as intermediate hosts. If this be so, it is further certain that important structural changes with ecdysis follow after their escape from the earth-worms or other annelids, moisture, dew, or water being essential to the penultimate stage of growth. Final passive transference, either with fresh fodder from swampy grounds, or, it may be, from pond water, ultimately enables them to acquire their definite sexual form, size, and other adult characteristics. According to Megnin it is not the Strongylus filaria, but a hitherto unknown and totally distinct species (Strongylus minu- tissimus) which occasions pneumonia in Algerian sheep. In England the parasitic bronchitis affecting sheep is generally called the "lamb disease." This is unfortunate, because many other parasites prove destructive to lambs. One of the most injurious species is Strongylus contortus, infesting the true stomach, whilst 8. hypostomus, occupying the small intestines, is almost equally obnoxious to the ovine bearer. By Leuckart and others this last-named worm is retained in Dujardin's genus Dochmius, in which genus another species occurs (D. cernuus). This worm is quite distinct, but not readily distinguishable by the naked eye alone. It occasionally occupies the upper part of the colon, as well as the lower end of the small intestine. A rarer intestinal worm in lambs is the Strongylus filicollis. Several other stron gyles infest the ox (S. radiatus, 8. inflatus, S. gigas), goat (S. venulosus), and stag (S. ventricosus) . As showing the extraordinary prevalence and destructiveness of entozoa in certain countries, I will adduce an instance in which my opinion was requested and given some five years since. My informant stated the case somewhat in the following manner : On a farm in New South Wales, and lying about 200 miles to the north-west of Sydney, on the Trafalgar tributary of the Macquarie river, out of a flock of about 8000 sheep no less than 1200 have perished. In many instances post-mortem examinations were made, worms appearing in all cases to be the cause of death. There were four kinds of parasites present. The most numerous were red and white, fe marked like a barber's pole." These occurred chiefly in the fourth stomach and commencement of the duodenum, but some were found throughout the entire length of the small intestine. A second set comprised small black worms, resembling needles, scattered only in the lumen of the intestines. The third set were tapeworms, KUMINANT1A 347 each being several fathoms in length. The fourth set was made up of white threadworms, individually measuring two inches in length. These occupied the bronchial tubes, and where charac- terised by my informant as " the most deadly of all/' Without the aid of specimens I at once recognised these brief diagnostic characters as severally referring to Strongylus contortus, Dock- mius hypostomus, Tania expansa, and Strongylus filaria. What the inquirer desired at my hands was " full informa- tion respecting the general principles to be carried out in view of the prevention of this parasitic disease, regard being had to the difficulty of finding any food but pasture, to the number of animals to be treated, and to the not unfavorable circumstance that the run is divided by fencing to a great extent." I was also requested to explain the best modes of treatment, being at the same time informed that turpentine drenchings had already been employed with only "partially effective" results. I was also expected to give numerous and varied formulae, to be tried in succession, supposing the first should fail. Of course, it should have been known that I neither prescribe medicines nor accept fees in respect of animal patients; but, as in this instance my opinion was permitted to assume the form of a " written scientific report," I was pleased to have an opportunity of com- menting freely and fully on the significance of the facts sub- mitted. My advice took the form of a long report, which might here be usefully given in extenso were it not somewhat of the nature of a private and privileged communication. I have no doubt that the stockowner would be pleased that I should utilise his remarkable " case " for the benefit of agriculturists and others ; but it is for him to publish the ( ' opinion " as it stands, should he think fit to do so. Practical men, on reading the few foregoing particulars, will perceive that one of the principal obstacles to success in cases of this kind lies in the circumstance that artificial food can only be procured with difficulty. Where the source of the disease is associated with the pasture- supply, any treatment, however effectual for a time, can only be followed by partially satis- factory results. The destructive powers of any one of the above-mentioned parasites being sufficient to produce a fatal lamb- disease, it is clear that when two or more of these particular species attack their victim in considerable numbers, the ovine-bearer has little chance of recovery. The intestinal strongyles, by means 348 PARASITES OF ANIMALS of their oral armature, behaving as veritable leeches, will, if not expelled in good time, produce a rapidly fatal anaemia, precisely in the same way as the human AnchyJostomum of the tropics. The worst of dealing with this sheep-parasite is that it will not succumb to ordinary doses of salines like the stomach stron- gyle ; moreover, the little leech-like wounds will probably bleed after the parasites have been compelled to abandon their hold. Prevention is better than cure. Accordingly, I sought to explain the origin of these creatures, and in what possible ways the germs of the various species could be destroyed, or at least limited in numbers. As to the drugs and inhalations to be employed, it would be difficult to advise any more effective than those commonly in vogue, the great thing being to effect changes of pasture and ground, to look to the purity of the water-supply, and to supply the best kinds of nourishment after active treatment. The diseased animals should, from the very first, be separated from their companions, because the amount of germ distribution is thereby greatly lessened. They should be at once drenched or treated by inhalation (as the parasitic nature of the attack requires), and the enclosure in which the animals have been temporarily housed should be thoroughly scoured with boiling- hot water impregnated with salt. The nomenclature of the parasitic diseases of animals is excessively vague. Thus, apropos to the case above recorded, I may mention that an American veterinary practitioner appeared to be much shocked that I should have had the temerity to speak of four distinct kinds of lamb-disease. It is in this way that practical men often commit serious mistakes by rolling together disorders that are totally distinct. If it were true that epizooty in lambs is exclusively due to Strongylus filaria, then profes- sionals might aptly speak of the parasitic bronchitis of young sheep as lamb-disease ; but we now know that several other helminths prove terribly fatal to lambs, occasioning death in totally different ways. In one set of cases the animals are asphyxiated ; in another set they become fatally anaemic ; and in a third set they perish from the severity of nervous reflex irritations. Lastly, it may be remarked that, in view of the successful management of the parasitic disorders of animals, the veterinary practitioner must necessarily be guided by the same general principles as the physician. For myself, I may say that I have hitherto designedly withheld many practical hints KUMINANTIA 349 which a long experience with human patients suggested, not wishing to appear to dictate to those who are constantly seeing animals. However, since (contrary to my own wishes) it has happened that both professional men and agriculturists have not only invited me to give opinions, but have, at various times, asked me to prescribe, it seems there can have been no impro- priety in publishing my views on this subject. Certainly I have had no professional motives to serve. Of the few non-strongyloid nematodes, one of the commonest is Trichocephalus affinis. I have obtained this worm from the giraffe, and the parasite may be said to infest all ruminating animals, not excluding even the camels and llamas. As before remarked, the whipworm has been known to produce severe symptoms in man, and it occasions " scour " in the sheep. The eyes of cattle are occasionally infested by Filaria lacrymalis and F. papillosa. The last named is the common eye-worm of the horse. On Feb. 27th, 1875, Dr Edward L. Moss, of H.M.S. " Alert/' brought me three examples of a nematode which I referred to Filaria terebra. Dr Moss obtained these parasites in 1874, during the time that he had charge of the Naval Hospital at Esquimalt, Vancouver's Island. They occu- pied the abdominal cavity of the black-tailed deer (Cervus columbianus) . The worms were mostly found lying amongst the coils of the small intestine. They were not attached to the peritoneal membrane. Dr Moss had shot seventeen deer in all, the males and females being in about equal proportion ; never- theless, not one of the bucks showed any trace of the presence of these entozoa. This absence of parasites in the male deer is noteworthy. Hitherto the worm appears to have been observed in the red deer (0. elaphus), and by Natterer in three species of American roe (C. rufus, C. simplicicornis, and 0. nambi). Two of the worms measured each about 2^" in length, the third exceeding 3". They displayed in profile two promi- nent oral papillae. Probably there were four of these processes, such as Dujardin described in his Filaria cervina, which, according to Diesing, is a synonym. They all possessed spirally twisted tails. Amongst the arachnidan parasites of ruminants having entozoal habits are Pentastoma denticulatum and P. constrictum. The former larval worm is excessively common in cattle, sheep, deer, and antelopes. According to Rhind, the adult worm (P. tanioides) also infests the sheep. The P. constrictum has 350 PARASITES OF ANIMALS hitherto only been found in the giraffe. On the 1 Oth February, 1859, I obtained numerous examples (P. denticulatum) from a bubale (Antilope bubalis) which died at the Zoological Society's Gardens. The greater number occupied the surface of the lungs and intestines ; some few, however, were enclosed in cysts beneath the pleura. In the spring of 1860 I also pro- cured several specimens from the abdomen of a cape guevi (Cephalopus pygmaus). The ectozoa of ruminants have received much attention, but I can merely indicate the known forms. Following Megnin's classification we have three well-marked varieties of the acarine genus Sarcoptes (S. scabiei, var. ovis, var. caprte, and var. cameli), two varieties of Psoroptes (P. longirostris , var. bovis and ovis), and Ghorioptes spathiferus. This last is the true mange mite of the ox (or Symbiotes bovis of Gerlach). A variety of the follicle mite infests the sheep (Demodex foil !<>/- lorum, var. ovis). Numerous species of tick (Ixodida) have been more or less fully described. Of these we have the Cara- partos of the Portuguese (Ixodes bovis), attacking cattle ; the J. reduvius, attacking sheep ; the I. plumbeus, said to attack lambs ; the I. albipictus and J. unipictus, found on the moose- deer. Probably this species also attacks cattle. A most horrible arachnidan is found on camels. I allude to Galeodes araneoides belonging to the Solpugidte. This parasite will bite severely any person who attempts to dislodge it from the bearer. Turning to the insects, we find ruminants liable to be annoyed alike by flies (Diptera), fleas (Aphaniptera) , and lice (Hemiptera) . Various species of four different families of flies are apt to prove troublesome. Of the OEstrida, attacking the ox, we have Hypo- derma bovis, whose larvae form tumours or warbles on the back ; also H. lineata, Dermatobia noxialis, and Gephenomyia bovis (mihi). The larvae of the latter reside at the root of the tongue and adjacent parts. In the sheep we have CEstrus ovis, (E. pur- pur eus, and Hypoderma lineata. Various species also attack goats and antelopes. Dr Kirk presented me with specimens of CEstrus from the frontal sinuses of a harte-beest or caama, and they have also been obtained from the sassabe, the saiga or colus, from the gnoo, and from the brindled gnoo, kokoon or gorgon. Mr Charles Danford presented me with several bots from an ibex. One or more species of Hypoderma have likewise been removed from the gazelle and other antelopes. The deer tribe are much attacked by bots. In the red deer we have Hyp. action KUMINANTIA 351 and H. diana, a species also infesting the elk. The throat-grubs are Ceph. rufibarbis and Pharyngomyia picta ; another species, also occurring in the fallow deer, Ceph. ulrichii, infests the elk, and G. stimulator the roe, the last-named deer being also infested by Hyp. diana. A throat- fly infests the reindeer, which is also frequently attacked by Hyp. tarandi. Specimens of the latter worm have been obtained by Dr Murie at the Zoological Gardens. The Hunterian Museum also contains these and other species of bots, presented by myself in Mr Andrew Murray's name. A subcutaneous bot has been found in the musk-deer. A throat- bot (G. maculate) infests the dromedary. In regard to the so-called free dipterous parasites and other noxious insects that attack ruminants, their name is legion. One of the worst is the tsetse (Glossina morsitans), immortalised by Livingstone. Of the Muscidce we have the ox-fly (Musca bovina), the sheep-fly (M. ccesar), and the executioner (M. car- nifex). Of the Tabanida we have T bovinus and T. autumnalis, Chrysops ccecutiens, and the allied Asilus crabroniformis (Asi- lida). Amongst the specially noxious insects must also be placed Stomoxys calcitrans and Rhagio columbaschensis. This fly proves fearfully destructive to cattle in Hungary and Servia. Lastly, I can only further mention the common Melophagus ovinus. This is nothing more than a gigantic louse, which from long use agriculturists and veterinarians persist in calling the sheep-tick. It belongs to the Hippoboscidcp, the members of which family only attack quadrupeds and birds. As regards the lice (Anoplura), I have to mention Haematopinus vituli of the calf, H. eurysternus of cattle, and H. stenopsis of the goat ; also Trichodectes scalaris, T. sph&rocephalus, and T. caprce. These infest the ox, sheep, and goat, respectively. For some account of the protozoal parasites (Psorospermia, &c.) infesting the flesh, of ruminants I must refer the reader to Book I, Section IV, Part YI of this treatise. BIBLIOGRAPHY (No. 49). (Anonymous), " On the Hydatid in the Brain of Sheep," from ' Journ. de Med. Yet.,' in ' Vete- rinarian/ vol. xxviii, p. 461, 1855. (Idem), " Note on the ' Kot in Sheep/ " ( Veterinarian/ vol. xxxvi, p. 100, 1863. (Idem), " On the Hydatid, or Tumour of the Brain (of Sheep)," under sig. of "Ben Ledi," in ' Veterinarian/ vol. xii, p. 467, 1839. (Idem), <{ Note on Rot in Sheep, Cattle, and Hares," from the ' Bristol Mirror and Scotsman/ in ' Veterinarian/ vol. xxxvi, pp. 156-7, 1863. (Idem), "Tapeworm Epizooty in Netting- 352 PARASITES OF ANIMALS hamshire," ' Brit. Med. Journ./ 1858. (Idem), " Prevalence of Kot in Sheep/' from ' Carlisle Journ./ in t Edin. Vet. Rev./ 1863. Baillet, " Filaria9 in the Eye of an Ox," from ' Journ. des Vet. du Midi/ in ' Veterinarian/ vol. xxxi, p. 703, 1858. Barnett, J., " Hydatids in the Liver of a Cow/' &c., ' Veteri- narian/ 1865, p. 236. Beale, L. S., " On Entozoa (?) in the Muscles of Animals destroyed by the Cattle Plague/' ' Med. Times and Gaz./ Jan. 20, 1866, p. 57 ; see also " Annotation," 'Lancet/ Jan. 13, 1866, p. 45, and 'The Microscope in Medi- cine/ 4th edit., 1878. Beneden (see Van Beneden). Bdlttnger, 0., " Echinococcus multilocularis in der Leber des Rindes," ' Deutsch. Zeitschr. f. Thier med./ ii, 1876, s. 109. Brauer (see Bibl. No. 50). Bugnion, E., " Sur la pneumonie vermineuse des animaux domestiques," ' Compt. Rend, de la reunion de la Soc. Helvet./ Andermatt, 1875. Chaignaud, "Worms in the Eyes of Oxen (with remarks by Desmarets)," from the French, in ' Veterinarian/ vol. i, p. 77, 1828. Gobbold, " Descr. of a new Trematode from the Giraffe," ' Rep. of Glasgow Meeting of Brit. Assoc./ 1854, and in ' Edin. New. Philosoph. Journ./ 1855. Idem, " On Flukes," ' Intellectual Observer/ Feb., 1862. Idem, " The common Liver Entozoon of Cattle," ibid., March, 1862. Idem, "The Whipworm of Ruminants," ibid., Dec., 1863. Idem, " Parasite-larvae," ibid., March, 1863. Idem, " On the Measles of Cattle and Sheep " (see various papers quoted in Book I, Bibl. No. 13). Idem, " On the Cattle-Plague Bodies (spurious Entozoa)," see Bibl. No. 41. Idem, " On the Fluke Parasites of our Food-producing Ruminants," Lect. iv of the Cantor series, pub. in 'Journ. Soc. Arts/ 1871. Idem, "Re- marks (&c.) in ref. to the Management of Sheep suffering from Nematoid Worms," 'Veterinarian/ Oct., 1876. Idem, "Record of preliminary Experiments with the Eggs and Embryos of the Husk-producing Strougyle of the Calf," ibid., Dec., 1875. Idem, in 'Entozoa/ pp. 145183; also in 'Manual/ and in the chap. on " Parasitic Diseases " contributed to ' Williams' Principles of Vet. Med.' Idem, " Remarks on Prof. Perroncito's Re- searches," 'Veterinarian/ Dec., 1877. Idem, ' Amphistomes of the Ox/ see Bibl. No. 51. Cooper, J., "Three Cases of Ccenurus in Calves," ' Veterinarian/ 1865, p. 357. Copeman, A., " Hydatids in the Brain of Lambs," ' Vet. Record/ vol. iii, p. 337, 1847. Cox, W., "Taenia in Lambs," 'Veterinarian/ vol. xxviii, p. 446, 1855. Creplin, fig. of Ampliist. crumcni- forum, in ' Wiegroann's Archiv/ 1847, tab. ii, s. 30. Crisp, E., RUMINANTIA 353 " On the ' Lamb -disease/ of which Parasites in the Lungs are generally the Cause or Consequence," repr. from ' Journ. of Bath and West of England Soc./ in July to October Nos. of < Edin. Vet. Rev./ 1868. Idem, "Note on Sir. filaria," ' Proe. Zool. Soc./ 18b6.Danford (see Cobboid, Bibl. No. 52). De Reck, " On the Draconcule (Strong, filaria aut veinulosus ?) of Lambs/' from 'Ann. de Logelin/ in ' Veterinarian/ vol. v, p. 521, 1832. Dupleune, " Hydatids in the Brain of an Heifer/' from ' Mem. de la Soc. Yet. du Calvados/ in ' Veterinarian/ vol. ix, p. 115, 1836. Dupuy, "An Hydatid in the Lumbar portion of the Spinal Marrow of a Lamb, aged eighteen months/' from ( Journ. Theorique et Prat./ in ( Veterinarian/ vol. iv, p. 285, 1831.- Engelmeyer, ' Thierarztliche Wochen- schrift/ 1850, p. 191. Findeisen, "Ech. in der Lunge," 'Repert. f. Thierheilkund/ 1875, s. 4,8. Fry, /., "Worms in the Trachea (of cattle)/' ' The Hippiatrist/ vol. iii, p. 5, 1830,Furstenberg, " On Pent, tanioides of the Sheep," ' Edin. Vet. Rev./ 1863. Gamgee, J., " On Parasitic Diseases/' extr. from his ' Rep. to the Privy Council/ ' Edin. Vet. Rev./ Dec., 1863. Idem, " On Cattle Diseases (including those produced by Entozoa)," from letters in the ' Times ' of Oct. 22, Nov. 10 and 13, &c. ; in 'Edin. Vet. Rev./ Dec., 1863. Idem, "On Diseased Meat (especially in relation to Trichina)," 'Pop. Sci. Rev./ Jan., 1864. Idem, " On Sturdy in Sheep (with figs, from Van Beneden, Leuckart, and Cobbold)," ( Edin. Vet. Rev.,' vol. i, p. 440, 1859. Idem, " Gleanings from the Researches of Eschricht, Haubner, A. Thomson, &c., respecting the Origin and Development of the Entozoa," f Veterinarian/ 1855. Giacomini (see Bibl. No. 13). Gulliver, "On the Structure of the Entozoa belonging to the genus Cysticercus," ' Med.-Chir. Trans./ ' Lond. Med. Gaz./ and 'Lancet/ 1840-41. Idem, " Notes on the Ova of Dist. hepaticum, and on certain Cor- puscles obtained from the genus Cysticercus," ' Proc. Zool. Soc./ March, 1840, and in 'Ann. Nat. Hist./ vol. vi, 1841; also 'Month. Journ. Med. Sci./ vol. ii, 1842, and 'Micros. Journ. and Struct. Rec./ p. 95, 1842. Hewlett (see Bibl. No. 13). Holmes, J., "Filaria in the Bronchi of a Calf," 'Vet. Rec.,' vol. i, p. 125, 1845. Hunter, J., " Ileum of a Ruminant containing Acephalocyst Hydatids /' see description of prepara- tion No. 863 in the ' Catalogue of Mus. Roy. Coll. Surg. Lond.' ("Pathology," vol. ii, p. 201), 1847. Idem, "Hydatid in the Humerus of an Ox" (ibid., prep. No. 864). Idem, "On 23 354 PARASITES OF ANIMALS Hydatids of the Sheep/' in supp. to his paper on ' Human Hydatids/ in ' Trans, of Soc. for the Improvement, &c./ vol. i, 1793, p. 34. Huxley, "On the Anatomy and Development of Echinococcus (from a Zebra)/' ' Proc. Zool. Soc./ and 'Ann. Nat. Hist./ 1852. KarkeeJc, W. F., " Notes on the Rot (or ties of the Cornish graziers)/' 'Veterinarian/ vol. iv, p. 573, J831. King, E., " On the Propagation of Rot (by means of the eggs of Fasc. hepaticd) in Sheep," 'Veterinarian/ vol. ix, p. 95, 1836. Krabbe, " Husdyrenes Indvoldsorme," ' Tidsskrift for Vet.' (See also my notice of the memoir in ' Lond. Med. Rec/ for 1872 ; repr. in ' Veterinarian/ May, 1873.) Kiichenmeister (see Bibl. No. 13). Leaver, T., " Cases of the Husk (from worms) in Cattle," 'Veterinarian/ vol. ii, p. 355, 1829. Lepper, " Hydatids in the Kidney of a Lamb (with remarks by Prof. Varnell)," ' Veterinarian/ vol. xxxvi, p. 524, 1863. Lewis (see Bibl. No. 13). Lord, J., "On some of the Parasites principally affecting Ruminants," 'Trans. Vet. Med. Assoc./ 1842-43. Masse (see Bibl. No. 13). Mayer, T., "On Hoose in Cattle (from Filaria)," 'Veterinarian/ vol. xiii, p. 227, 1840. M'Call, J., "On Sturdy in Sheep," ibid., vol. xxx, p. 267, 1857. Megnin, P., " Le Str. minutissimus," ' Bullet, de la Soc. Cen- trale Vet./ in ' Rec. de Med. Vet./ July, 1878, and in 'Ann. de Med. Vet./ Oct., 1878, p. 563. Moorcroft, "Brain Hydatids," 'Med. Facts and Observ./ 1792. Morton, W. J. T., " On the Entozoa affecting Domesticated Animals, and particularly on Fasc. hepatica or Liver Fluke in Sheep," ' Veterinarian/ vol. xii, p. 735, 1839. Hosier (see Bibl. No. 13). Murie, J., "On the occurrence of (Estrus tarandi in a Reindeer in the Zoological Society's Gardens," ' P. Z. S./ 1866, with woodcuts. Idem, " On a Leech (Trocheta) found in the Viscera of a Molluscan Deer (Gervus moluccensis, Miiller)," ibid., 1865. Numan, "Over den Veelkop-blaasworm der Hersenen " (this beautifully illustrated memoir, in the ' Trans, of the Dutch Soc. of Sciences/ supplies an elaborate bibliography of continental writings on Ccenurus cerebralisT. S. C.), ' CErste Kl. Verh./ 3e Reeks, 2e Deel, p. 225 et seq. Oliver (see Bibl. No. l3).Padley, G., 'On Entozoa from a Sheep / see Sandie. Parsons, " On Diarrhoea in Lambs (with bronchial worms)," 'Veterinarian,' 1855, p. 685. Patellani, " Sturdy in Cattle," from ' Munchen Jahresbe- richt/ in ' Veterinarian/ vol. xxx, p. 81, 1857. Pellizzari (see Bibl. No. 13). Pcn-oncito (see Bibl. No. 13). Poitrquier (see Bibl. No. 13). Ralph, T. S., " On the Parasitic Nature of EUMINANTIA 355 Pleuro-pneumonia/' &c., two papers in ' Austr. Med. Journ./ 1865. Ranke, " Pulmonary Entozoic Disease of Sheep/' ' Path. Soc. Trans./ 1858 ; see also ' Veterinarian/ vol. xxx, p. 708, 1857. Raynaud, " A Word on the Cachexia, or Rot in Rumi- nants/' trans, from the ' Journ. des Vet.,' by W. Ernes, in 'Veterinarian/ vol. xxxiii, p. 488, 1859. Read, R., "Destruc- tion of Strongylus and Filaria in the Bronchial Passages of Calves, through nasal inhalation of ether, chloroform, oil of turpentine, or rectified oil of amber," ' Veterinarian,' vol. xxi, p. 604, 1848. Reck (see De Reck) ..Reed, R., " Congenital Hydatids in a Lamb," ' Veterinarian/ vol. viii, p. 551, 1835. Rhind, " Description of a species of Worm (Pentastoma) found in the Frontal Sinus of a Sheep/' ' Farrier and Naturalist/ vol. iii,p. 277, 1830, and ' Lancet/ 1829. Robertson, "Remarks on Tasnia in Lambs," ' Rep. of Scottish Med. Vet. Soc./ in 'Veterinarian/ 1875, p. 80Rochard (see Bibl. No. 13). Rose, G. B.j " On Ccenurus and Acephalocysts," ' Lond. Med. Gaz./ vol. xxiv, p. 525, 1844. Idem, " On the Anat. and Physiol. of the Cysticercus tenuicollis" ' Roy. Med.-Chir. Soc. Trans./ and 1 Lancet/ 1848. Idem, " On the Vesicular Entozoa, and par- ticularly Hydatids," 'Lond. Med. Gaz./ vol. xiii, p. 204, 1833- 34. Sandie (with Padley), " On Entozoa in the Lungs of a Sheep," 'Ann. Nat. Hist./ 1849. ScMarzmeier. "Die Trepa- nation des Rindes bei Coenurus," 'Wochfenschr. f. Thierheilk./ 1875, s. 295. Shenton, "Worms from the Stomach of a Cow," 'Veterinarian/ 1844, p. 487. Siedamagrotzky, "Hydatids in the Liver of a Cow," ' Bericht lib. das Veterinawesen im Kon. Sachsen/ 1875, s. 29. Simonds, J. B., " Death of Sheep from Worms in the Stomach (abomasum), being remarks on Mr, Haywood's case," 'Veterinarian/ vol. xxxiv, p. 525, 1861. Idem, ' The Rot in Sheep, its nature, cause, treatment, and prevention/ London, 1862. Idem, "On Filarise in the Bronchi of Calves," 'Trans. Vet. Med. Assoc./ 1843, p. 517. Idem, " On Strongylus in the Bladder and Intestines," ibid., 1843. Idem, " On Hydatids of the Liver of a Sheep (Mr Scruby's case)," ibid., p. 331. Idem, " On Disease of the Mesenteric Artery from Strongyli within the Vessel," ' Path. Soc. Trans./ 1854. Idem, "Lecture on the Nature and Causes of the Disease known as Rot in Sheep," vol. xxxiv, p. 274, 1861. Spence, G. W., " On CEstrus of the Ox," ' Edin. Med. Journ./ 1858, and 'Edin. Vet. Rev./ vol. i, p. 400. St Cyr (see Bibl. No. 13). Stoddart, J., " Case of Hydatids in the Liver (of a Cow)," 350 PARASITES OF ANIMALS 'Veterinarian/ vol. xi, p. 637, 1838. Button (Lecture), ' Gardiner's Chronicle/ June 29, 1872. Sylvester, F. R., "Cases of Parasites infesting the Brains and Intestines of Lambs/' ' Vet. Rec./ vol. ii, p. 40, 1846. Thudichum (se"e Bibl. No. 13). Idem, " Echinococci from the Sheep's Lungs/' ' Rep. Med. Soc. Lond./ in 'Assoc. Med. Journ./ 1856, p. 195. Tommasi (see Bilb. No. 13). Van Beneden, "On the Development of Coenurus," from ' Comp. Rend.,' in ' Ann. Nat. Hist./ vol. xiv, 1854. Watson, K. W., " Experiment for the Cure of the gidd (Coenurus) in a Sheep," ' Lond. Med. Repos./ 1815. Willemoes- Suhm, in < Sieb. and Koll. Zeitschr./ Bd. xxv, s. 176. Wilson, E., "On the Anatomy of Trichocephalus affinis," 'Vet. Rec./ 1846. Wymann, "Note on Filaria in the Bronchi of a Sheep," see Anon, on " Entozoa and Parasites," in ' Amer. Journ. Sci./ vol. xxxix, p. 183, 1840. Youatt, " On Hydatids in the Sheep (symptoms, prevention, treatment, &c.)," ' Veterinarian/ vol. ii, p. 519, 1834. Idem, " On the peculiar Bronchitis in young Cattle, accompanied by Worms in the Bronchial Passages," part of lecture, in ' Lancet/ 1832. Idem, " Hydatids in the Brain of a St Domingo Goat," 'Veterinarian/ vol. ix, p. 443, 1836. Idem, "Bronchitis from Worms (in Cattle)," ibid., vol. vi, p. 177, 1833. Idem, "Hydatids in the Brain (in Cattle)," ibid., vol. vii. Yvart, "Brain Hydatids," ibid., 1828, p. 19. Zahn, " Lungenwiirmer beim Reh," ' CEsterr. Vieteljahrschr. f . w. Vet./ 1875, s. I2b.Zurn (see Bibl. No. 13). For further references to the literature of Hydatids in Animals, see Biblio- graphy No 20, o, in the first half of this work. PART IX (SOLIDUNGULA). It will naturally be expected that I should give a full account of the parasites of the solipedal, solidungulate, or equine mammals. As regards the horse I regret that I cannot meet this expectation in so complete a manner as the subject deserves ; nevertheless, with the aid of an extended biblio- graphy the summary here offered will be found to be tolerably exhaustive. At all events I think I may say that no similar record has hitherto been attempted. The liver fluke (Fasciola hepatica), though not very frequent in the horse, is not uncommon in the ass. In dissecting-room subjects at the Royal Veterinary College it is often encountered. SOLIDUNGULA 357 In France it was originally found in the horse by Daubenton. As I learn from Sonsino, Dr. Abbate Bey recently recorded a similar find at Cairo. In solipeds generally the liver fluke appears to be almost harmless, for, notwithstanding the fright- ful ravages produced by rot amongst a variety of animals besides sheep, we have no evidence of the destruction of horses from this cause. In the German outbreak of 1663-65 multi- tudes of cattle and deer perished, and in the French outbreak of 1829-30 five thousand horned beasts succumbed in the arrondissement of Montmedy alone. In neither of these epizootics were the solipeds affected. More importance attaches itself to the study of the amphistomatoid flukes. These parasites, though in a scientific sense only recently discovered in equine bearers, have been long known to the natives of India. Thev appear to be capable of producing serious intes- tinal irritation. I have described two forms (Amphistoma Gollinsii and A. Coll., var. Stanley i), which infest the colon. The specimens sent to Prof. Simonds from India by Mr Stanley, Y.S., were much larger than those sent to me from Simla by Mr Collins, Y.S., some ten years later (1875). As in all other amphistomes obtained from the intestines of elephants and cattle, the worms, when fresh, were of a bright brick-red color. By the natives of India these parasites are called Masuri ; but no description of the worms had been published prior to the account which I gave of the contributions forwarded by Major- General Hawkes, Mr Collins, and Mr Stanley. I shall have occasion to speak of the elephant's Masuri farther on ; but in the meantime I must remark that the generally received notion as to the parasitic cause of the earth- eating propensities of various animals seems to have some foundation in fact. Not alone from Major-General Hawkes in Madras, from Mr Folkard in Ceylon, and from various other trustworthy sources, have I been informed of this habit on the part of Indian horses, but Dr Howe told me that Australian horses, and even sheep, infested with stomach- worms, are in the constant habit of consuming large quantities of sand. From all the facts that have come before me, I am inclined to think that gastric or intestinal irritation, however brought about, may induce the habit in question, parasites being only one of the many sources of irritation giving rise to symptoms of colic in solipeds and pachyderms alike. At all events the African elephants at the London Zoological Society's Managerie, as 358 PAEAS1TES OF ANIMALS repeatedly witnessed by myself, are in the habit of swallowing large quantities of soft mud during the summer months, but no traces of masuri have as yet been detected in their faeces. When by letter I informed Major-General Hawkes of an inte- resting find by Mr Collins of about a thousand Amphistomes in the colon of a horse that had died at Simla, the announcement called forth a reply which is sufficiently instructive to be quoted. Writing from Secunderabad in July, 1875, he says, respecting this " find : " " Your statement has incidentally thrown light upon a subject which has puzzled many of us in this country. It occasionally happens that a horse, on being opened after death, is found to have accumulated in his intestines large quantities of sand and gravel. In a recent case this accumula- tion amounted to 14J Ibs. Until recently it was always held that this gravel or sand could only be introduced with the animal's food. All grain in this country is trodden out by bullocks on an earthen floor, and the grain undoubtedly contains a proportion of sand and gravel derived from this source. Although this ought to be carefully washed out before it is given to the horse, still, owing to the carelessness of the native horse- keepers, this cleaning is, I expect, often omitted. In the daily ' feed ' of eight or ten pounds of grain given to each horse the utmost quantity of sand or gravel that could be found admixed therewith would not probably exceed two or three ounces; consequently it would take from 77 to 116 days to accumulate so large a quantity as 14 J Ibs. Now, the advocates of the theory of the gradual accumulation of sand in this way have never been able to explain why the grain, grass, hay, and other ingesta should pass in the ordinary way through the intestines, whilst this sand or gravel remains behind. One can understand the possibility of such substances as wool, hair, or similar matters concreting in the alimentary canal, though I believe they are usually found in the stomach, and not in the intestines ; but how a most incohesive substance like sand can possibly accumu- late in the gradual way required by their theory I have never heard even plausibly explained. On the other hand, the fact that horses are often excessively addicted to eating earth is well known ; and if my memory serves me correctly, it was found necessary, about twenty years ago, to remove the mud- walls of the pickets surrounding some of the horses of a mounted corps in this presidency in consequence of this habit. SOLIDUNGULA 359 Now, given the fact that the amphistoma has been found in the horse (as your specimens prove), may we not fairly suppose it possible that the animal resorts to the same mode of ridding himself of this parasite as does the elephant ? and also, would it not in a much more natural manner account for the large quantity of gravel or sand found in the intestines than does the theory of gradual accumulation ? Eeasoning from analogy, as in the case of the elephant, this eating of earth in the horse would be an instinctive effort on the part of the " host " to rid himself of the parasite. This self-taken remedy is doubtless in many cases quite effectual, though unnoticed. The fatal cases are probably those in which the horse has either overdone the remedy or where the system was too de- bilitated to carry off a quantity of sand or gravel that would otherwise have safely passed through the intestines of a horse in more robust health. The actual fact must, of course, be verified by careful investiga- tion." Closely allied to the Masuri is an amphistome which I originally named Gas- trodiscus Sonsinoii, but which should be altered as opposite (Fig. 62). It exceeds \" in length and J" in breadth (16 mm. long by 10 broad). Its dis- covery by Dr Sonsino was one of the results of his examination of sixteen carcases of soli- peds that died during the Egyptian plague of 1876. Specimens having been forwarded e FIG. 62 Gastrodiscus Sonsinonis. a, Mouth; b, caudal suclcer and posterior mesial cleft; c, left lip of the gastric disk; d, anterior mesial cleft; e, e, gastric suckerlets; /, reproductive papilla. Enlarged. Original. 3GO I'AKASITKS <)F ANIMALS to Panceri, Von Siebold, Leuckart, and myself, most of us at once agreed that the worm was new to science. Pointing t<> the genera, Notocotylus and Aspidocotyliis, I explained its close affinity to the latter more particularly. Whilst Notocotylus has fifty supplementary suckers on its back, Aspidocotylus has nearly two hundred small ventral suckers seated on a convex disk. In Gastrodiscus a still larger number of suckerlets are placed in the deep concavity of a large gastric disk formed by the outstretched and inrolled margins of the body of the parasite. Zoologically speaking, the odd thing about this singular worm lies in the circumstance that its nearest fluke-relation, so to speak (Aspidocotylus mutablis), dwells in a spiny-finned fish (Cata- phractus) ; and this fish itself forms an aberrant genus of the family to which it belongs (Triglidae). From what has been said it will be seen that our Gastrodiscus must not be confounded with Cotylegaster cochleariform (or with its synonym Aspidog aster cochleariformis) , to which parasite Von Siebold was, I believe, induced to refer it. Like most of the true amphistomes, the worm in question infests the intestines. Although discovered by Sonsino at Zagazig in plague-nffected corpses, there is no reason to suppose that this helminth was in any way etiologically connected with the Egyptian epizooty. The tapeworms of the horse are of great interest practically. Excluding Sander's Tania zebra, which was doubtless T. plicata, at least five species have been described, but they may probably be all reduced to two distinct forms and their varieties. Whilst Taenia plicata acquires a length of three feet, the strobile of T. perfoliata never exceeds five inches. The lobes at the base of the head in the latter are distinctive. The former is usually confined to the small intestine, but the perfoliate worm often occupies the caecum and colon in great numbers. As regards T. mamillana, I may say that neither Gurlt's descriptions nor his figures are convincing. The worm is, I believe, identical with T. perfoliata. In like manner, after going into the matter with some care, I am accustomed to speak of Megnin's T. inerme as T. perfoliata, var. Megnini, and of Baillet's T. innome as T. perfoliata, var. Bailletii. I have examined great numbers of equine tapeworms, but whether my determinations on this point are correct or not, the case recorded by Megnin is of remark- able interest. Clinically, indeed, it is not entirely unique, since a somewhat similar case has been recorded by Mr Poulton. In Megniu's equine patient the autopsy revealed the presence SOLIDUNGULA 361 of 200 bots, 153 lumbricoids, upwards of 400 oxyurides, and several thousand palisade worms, besides numerous tape- worms. In Mr Poulton's patient large quantities of tape- worms were found in the duodenum (and in large sacs of the walls of other sections of the small intestine), and also myriads of the little four-spined strongyle, in addition to about a score of palisade worms. Both Megnin's and Poulton's patients died suddenly; but the great interest attaching to Megnin' s case arises from the boldness of manner in which the French savant interprets the phenomena of the intestinal sacculation in relation to the development of the tapeworms. M. Megnin assumes that the sacs are due to the formation of polycephalous or ccenuroid scolices. Without contradicting Megnin' s ingenious interpretation of the phenomena in question, I may say that the difficulty I have in accepting his view arises from the circum- stance of the rarity of the occurrence of these sacs. In Poul- ton's case of Tania perfoliata, the sacs were present, and they were productive of similar results ; but in the scores of other recorded cases of sudden death from the same species of tape- worm (as published by Mr Bees Lloyd, and myself), the pre- sence of such sac-formations is not once mentioned. To be sure, their presence may have been overlooked, but this is scarcely likely, seeing the great care taken by Mr Lloyd in conducting the autopsies. I cannot dwell upon the subject at greater length. The presence of so many sexually-immature strobiles, combined with the existence of the intestinal wall sacs, certainly does seem to point to the existence of ccenuroid bladder-worms, but until the existence of the polycephalous scolex be actually demonstrated one must be cautious in con- cluding " that the horse nourishes at the same time the strobila and scolex of the unarmed tapeworm/' Practically, we now know for certain that not only are tapeworms capable of pro- ducing a fatal issue in isolated cases, such as those recorded by Megnin and Poulton, but that they may also be productive of disastrous epizooty, as proved by Mr Lloyd in the case of Welsh mountain ponies. In this connection I may perhaps be pardoned for saying that this discovery in 1875 was one of the practical results directly issuing from the publication of my e Manual' 1874. The attention of the veterinary profession been called to the subject of parasitic epizooty, Mr JKloyd was the first to make search for helminths amongs^f some 362 PARASITES OF ANIMALS few of the carcases of the hundred and more equine animals that perished in South Wales. Two totally distinct epizootics pre- vailed. In the Beacons district tapeworms alone were the cause of .death, whilst in the Deangunid district scores of animals perished from strongyles. In another district a hundred animals perished from tapeworms. These parasites I identified as examples of Strongylus tetracanthus and Tania perfoliata. Taking all the helminthological facts together we have made a great advance both in hippopathology and equine epidemio- logy; and, as I observed at the time, the scepticism which not unnaturally still exists (in reference to entozoa as a frequent cause of death amongst animals, both wild and domesticated) will sooner or later be dispersed by that wider attention to the subject which our labors have invoked. In relation to equine disease the facts brought forward are too important to be dismissed in a single paragraph. As two distinct kinds of parasitic epizooty were discovered, the circumstances connected with their separate detection must be noticed at greater length. Further on, I shall again deal with the helminthiasis due to strongyles. It was on the 17th of April, 1874, that I received from Mr Lloyd, of Dowlais, Glamorganshire, a communication calling my attention to a fatal epizootic affecting ponies. He supposed the outbreak to be due to parasites. On the following day I also received a parcel containing portions of the lower intestines, which had been removed from one of the diseased animals. The victim in question, a pony mare, had died on or about the 12th of April, at Llangunider, Breconshire. Mr Lloyd states in his letter that he " presumes " that the pony's death was caused " by the presence of small worms," examples of which he now for- warded for the purposes of identification and investigation. He also sent some equine tapeworms. Mr Lloyd had already inferred that his small worms were " strongyles ;" and in regard to the tapeworms he says: " This species of parasite has caused, or is supposed to have caused, the death of at least one hundred mountain ponies." The investigation being immediately pro- ceeded with, I may so far anticipate my record of the results obtained as to state at once that the facts observed by me con- firmed Mr Lloyd's suspicions proving, beyond a doubt, that the pony above mentioned had succumbed to injuries inflicted by myriads of minute strongyles. Not only did I find the faecal matter of the colon loaded with mature strongyles, but SOLIDUNGULA 363 the walls of the intestine were also occupied with encysted and immature forms of the same nematode species. To such an extent had infection taken place, that I was enabled to count no less than thirty-nine strongyles within the space of the one fourth of a square inch. All parts of the sections of the colon under examination were almost equally invaded ; so that, taking the average, I am clearly within the mark in saying that every square inch of the gut yielded at least one hundred parasites. The walls of the entire colon must therefore have been occupied by tens of thousands of these creatures, to say nothing of the scarcely less numerous examples lying free or lodged within the faecal contents of the bowel. In a second and more extended communication, sent in reply to inquiries as to the cestodes, Mr Lloyd (whose letter I have abridged) writes : " I regret that I cannot give you very full particulars respecting the tapeworms. During the last twelve months mountain ponies grazing on the lower districts of Breconshire, which comprise some of the highest mountains in South Wales, have been dying in great numbers, from what the farmers indefinitely term inflammation. From what I have seen and heard, it appears that there are three causes of death, the tapeworm, the small worms (which I presumed were a kind of strongyle), and catarrhal disorders, such as have been common among horses of late. By far the greater number of deaths (from what I can glean) have been caused by the parasites. In the Ystradfellte or Penderin districts there has been no investi- gation, although the disease has reigned there for a longer period, about eighteen months, with (from what I have heard) a larger number of deaths than elsewhere ; so I shall let these remain for the present, as I have not had an opportunity to see or hear anything authentic about them. In the Talybont district the cause appears to be the small worms (like those I sent). The owner of the animals said that a month ago, when he went to look after his ponies, they were appearing quite well, and looked as well as he could expect them at this season, but he was astonished to find some of them a fortnight ago looking very lean and wasting, and he thought that the weather was the cause of it, yet resolved to see them of tener ; the next time he saw them one was dead, and knowing of the loss in the neighbourhood, and fearing he would be a sufferer, he sought aid, applying to me. When I arrived two days following two more were dead, and they presented an emaciated appearance. 364 PARASITES OF ANIMALS The post-mortem examination revealed a healthy condition of the whole of the intestines, save slight thickening of some parts of the colon and rectum, which contained, enclosed in the mucous membrane, in cysts or minute sacs, worms coiled upon themselves. Each cyst, containing one worm, was best seen by transmitted light. The colon was nearly full of faecal matter, which contained thousands of parasites scarcely visible. The largest were very few in number, not exceeding an inch in length and barely one sixteenth in diameter at the middle portion. They somewhat tapered at both ends. The caecum was half full of fluid faeces, containing no visible worms ; the rectum, with faeces of natural consistence, the examination of which reavealed only two or three evident worms ; so that the examination of faeces of living animals giving results like this would not assist the diagnosis, unless suspected. Small intestines these latter contained about a dozen bots, which were nearly free, but had pierced to the muscular coat. I should think they had participated in the disease. The right lung had been slightly congested ; nothing else abnormal to be seen. Possibly congestion of lungs would arise from the distress when pained with worms, for the pony was found on its back with its head in a thicket it had not appeared to have struggled with its teeth firmly closed. " Respecting the animals affected with Taenia, it is remark- able that, as a rule, they are in fair condition. The average time they appear to be troubled with the worms is two months, and the symptoms observed have been many. They are at first seen to be unable to keep up with the other ponies, ex- tending the head and turning the upper lip up, rubbing the quarters, staring coat, suddenly appearing distracted, seizing turf in mouthfuls when being griped or pained, others running away as fast as they can go, or rolling and kicking on the ground for five or ten minutes, then walking away as if nothing had happened, if coming down a slope quickly almost sure to fall headlong, easier caught, not unfrequently coughing, groaning noise, appetite good, and, what is peculiar in some of them, lame- ness of one of the hind limbs, mostly the near hind leg, with slight knuckling over at fetlock. " Post-mortem appearance. Abdominal viscera normal, save rectum, which is in some places slightly congested ; colon nearly full of faeces, no worms ; caecum, in which worms are alone found, is nearly full of faecal matter of thicker consistence SOLIDUNGULA 365 than usual, and nearly half made up of worms ; stomach half full of partly digested food ; heart and lungs healthy ; Schnei- derian membrane injected ; mucous membrane of trachea and part of larger bronchiae of a more or less livid colour (which may be owing to asphyxia) ; corner of tongue bitten off ; mouth very close. " Several animals were found at times lying dead together. " Of the Ttenia as many as three or four ponies, which some hours previous had been seen grazing unaffected, were found dead on the same spot ; and this to my own knowledge, one farmer having lost ten. " Of the small worms I have been told by a farmer that in his district one of his neighbours had lost twelve ponies."" As I had partly misunderstood my informant's original statement, Mr Lloyd, in a third communication, repeated the evidence, emphatically reminding me that " the ponies affected with tapeworms are in a district six or seven miles distant from those affected with strongyles. Those troubled with tapeworms are in good condition, as a rule, up to death ; they are noticed to be troubled generally for two months previous to death, and may be seen at one hour grazing and apparently well, and dead or dying the next hour. As many as four have been found dead at the same spot. In this (the Beacons) district the tapeworms alone have been found and not a single strongyle. In the Deangunid district strongyles only have been found, such as I sent you. The ponies have been noticed ailing for three or four weeks, becoming rapidly emaciated and dying from exhaustion. In tapeworm-affected animals the caecum is nearly half full of these parasites. The animals thus affected are on the red sandstone formation, whilst those affected with strongyles occur on the limestone formation the latter affording the drier situation."" Being on the teaching staff of the Royal Veterinary College I was particularly glad to have the authority of an experienced veterinary practitioner to testify to the injuriousness of Tcenia perfoliata in the horse. Over and over again I had pointed out to the members of my class the desirability of examining the faeces of solipeds where obscure symptoms of intestinal irrita- tion existed. Not only so ; at the request of friends I wrote out prescriptions suitable for equine patients suffering from tapeworm. I felt the more indebted to Mr Lloyd, inasmuch as his practical views served to strengthen the propositions I had advanced in 366 PARASITES OF ANIMALS connection with internal parasites as a frequent cause of epizo- otics. My views were criticised at the time with a vigour and warmth well worthy of those who are afraid of advancing epiderniological science too rapidly ; but it seems that so far from my having overstepped the bounds of moderation in this matter I had, in reality, been too cautious. Certainly it can now no longer be said that " the symptoms created by tape- worms in the horse are of little or no consequence." Here, therefore, I repeat, we have made a clear and rapid advance in our knowledge of helminthic disease ; and from the impulse thus given to hippopathology it is only reasonable to look for still further advances in veterinary medicine. By-and-by, the scepticism which not unnaturally exists in reference to entozoa as a frequent cause of death amongst animals, will be dispersed by even yet clearer enunciations regarding the important part these parasites play in the destruction of our most valuable creatures. Apart from the question incidentally raised by Megnin as to their origin and mode of development, the presence of larval cestodes in horses cannot be passed over. The common hydatid (Echinococcus veterinorum) , though not of frequent occurrence, is occasionally productive of fatal consequences. Very inter- esting cases are recorded by Messrs Henderson and Kirkman, aided by the valuable comments of Professor Varnell. Mr Hutchinson observed an hydatid in a horse's eye, and Mr Vin- cent noticed lameness, as resulting from hydatids. But one of the most interesting cases of hydatids in solipeds is that described by Professor Huxley, from a zebra that died at the Zoological Gardens in 1852. As stated in Huxley's elaborate memoir (freely quoted in the first part of this work), the liver was found to be " one mass of cysts, varying in size from a child's head downwards." The zebra's death was purely acci- dental, as it broke its neck while at play in the paddock. The long bladder-worm of the horse (Cysticercus fatularis) is entirely unknown to me, and, as before suggested, may be a mere variety of the C. tenuicollis of ruminants. An authentic in- stance of the occurrence of the gid hydatid (Coenurus cerebralis) in the horse is recorded by Gurlt. Lastly, in relation to the question of food, it is worthy of remark that whilst beef, veal, pork, and even mutton, are apt to be measled, the muscle -flesh of horses is not liable to be infested by Cysticerci. This is a fact in favor of hippophagy. SOLIDUNGULA 367 The nematodes of solipeds are very numerous, and first in importance must be placed the palisade worm (Strongylus armatus). This worm was known to Euysch (1721). The old naturalists recognised two varieties (major and minor). These we now know to be merely the final stages of growth of one and the same entozoon ; and in both stages the worm inflicts severe injury upon the bearer, chiefly, however, whilst wander- ing through the tissues. The palisade worm has acquired no- toriety principally on account of its causing verminous aneurism, nevertheless, this pathological change is not, in itself, the most disastrous evil produced by the worm. In the adult state the female reaches a length of two inches, whilst the male rarely exceeds an inch and a half. The posterior ray of the caudal membrane or hood of the male is three- cleft. In both sexes the head is armed with numerous, closely- set, upright denticles, presenting the appearance of the teeth of a circular saw or trephine. The eggs are elliptical and somewhat constricted at the centre, their contents forming embryos after expulsion from both parent-worm and host. The larvae are rhabditiform, changing their skin, in moist earth, in about three weeks, at which time they part with their long tails. According to Leuckart, they pass into the body of an intermediate bearer before entering the stomach of the definitive or equine host. From the alimentary canal they pass to the blood-vessels, causing aneurism, and thence they seek to regain the intestinal canal, where they arrive at sexual maturity. It is during their migratory efforts that they give rise to dangerous sym- ptoms in the bearer, not unfrequently causing the death of young animals, especially yearlings. In the adult state the worm is also dangerous to the bearer, as it produces severe wounds by anchoring to the mucous membrane of the gut. The proofs we possess as to the frequency of abdominal, espe- cially mesenteric, aneurism from this source are overwhelming. Prof. Bruchmiiller estimated the percentage of aneurismal horses, six years old and upwards, at 91 per cent., and it is a matter of common observation in veterinary dissecting rooms that verminous aneurism is rarely or never absent in the ass. Professors Dick, Simonds, Pritchard, Williams, and many other English and Scotch veterinarians of eminence, have all borne testimony of this kind, and, for myself, I may say that one of the earliest pathological appearances with which I became familiar, some thirty years back, was that presented by mesen- 368 PARASITES OF ANIMALS teric arterial disease of the ass. In relation to fatal colics in the horse the study of verminous aneurism is of the highest moment. On this subject Prof. Friedberger has published some valuable lectures, in which, amongst other points, he incidentally remarks upon the comparative freedom of military horses from aneurism as compared with ordinary laboring horses. This arises partly from the fact that the latter are not cared for to the same extent, dietetically and otherwise; and, moreover, cavalry horses are, as a rule, younger than ordinary working animals. Whilst Friedberger, in his suggestive brochure, does ample justice to the writings of his colleague, Dr Bollinger, it may be said, in like manner, that he does not fail to recognise his great indebtedness to the researches of Leuckart. So practically important, however, do I deem Bellinger's summary of the whole subject in relation to the hippopathological aspects of parasitism, that I feel it desirable to record his conclusions at full length. No professional man having any pretensions to a knowledge of the veterinary art or, for that matter, to parasitism in relation to sanitation should remain uninformed on this subject. Dr Bollinger's results are thus stated : 1. The worm aneurism of the visceral arteries of the horse, existing in 90 to 94 per cent, of adult horses, has a general correspondence with the aneurisma verum mixtum of man. It is, however, distinguishable from the same by its seat, cause, character of its walls, contents, and mode of termination. The worm-aneurism arises from a parasitism of the palisade worm (Strongylus armatus), owing to an inflammatory affection of the arterial walls which it causes, and which one may describe as a recurrent traumatic endo-arteritis. This holds good for all the visceral arteries, with the exception of the abdominal aorta, in which an aneurism may arise from local increase of pressure. ' 2. The formation and further development of the aneurism is also favored by the narrowing of the arterial calibre, which is caused by the inflammatory swelling of its walls, and also by the contemporaneous formation of a thrombus (clot), this latter still further supporting and exciting the inflammation of the inner coat. 3. Whilst the causes above mentioned (and of these more particularly the continued presence of the palisade worms and the plugging of the smaller arteries by thrombi) favor the growth of the worm-aneurism, the small size of the same, not- withstanding the years it has existed, is explained by the con- SOLIDUNGULA 369 siderable hypertrophy of the muscular layer, by the tough fibrous capsule formed in many cases by the connective tissue of the mesentery, and by the adhesion of the intestines to the perpen- dicular and free-lying anterior mesenteric artery ; in particular this last-named circumstance does not allow of any very consider- able shortening of the mesenteric artery, which would necessarily be accompanied by considerable dilatation of the arterial tube. 4. The favorite seat of the worm-aneurism is the trunk of the anterior mesenteric artery, directly at its origin from the abdo- minal aorta. Most frequently that part of the arterial trunk is dilated from which the arteria ilea, csecales, and colica inferior (arteria ileo-cceco-colica) arise, less frequently the arteria colica superior at its origin, and the arteries of the caecum and colon in their course in the meso-caecum and meso-colon. The verminous aneurism also occurs in the coeliac artery (Bauch- schlagader), in the posterior mesenteric artery (Gekros-arterie), in the renal artery, and in the abdominal aorta. A horse is not unfrequently afflicted with several aneurisms of this kind at one and the same time. Thus in one case (described by Bellinger) there were six of these aneurisms affecting the abdominal aorta and its branches in the same horse. The verminous aneurism may occur from the sixth month of life onwards, and with increasing age ; the number of horses free from such aneurisms becomes continually smaller. 5. The size of the aneurism varies between that of a pea and that of a man's head. The dilatation is, as a rule, equal on all sides, the form being usually thumb-shaped or bottle-shaped, passing into that of a cone or long oval figure. This general configuration is principally due to the free and moveable situa- tion of the anterior mesenteric artery. 6. In contrast to aneurisms in man, the walls of the worm- aneurism of the horse are almost without exception indurated. In addition to the mesenteric connective tissue, all the arterial coats, and especially the tunica media, generally take part in this induration. The hypertrophy of the media, which stands unique in respect of what is known of arterial disease, forms a compensatory action of the arterial wall, analogous to the muscular hypertrophy of the heart in valvular disease. This change in the media points to the fact that in the development of aneurism in man the early disturbance of the nutritive pro- cess in the tunica media is not a less essential factor than the degeneration of the tunica intima. 24 370 PARASITES OF ANIMALS The changes in the intima are the least constant. They present all stages of progressive and retrogressive metamor- phosis, from simple induration to ulceration and calcification. In the walls of the verminous aneurism one not unfrequently finds all the pathological changes exhibited by atheroma in man. Calcification is a common form of the retrograde process, and, in very rare cases, may pass on to the formation of true bone. 7. In addition to the palisade worms, one almost constantly finds a parietal thrombus contained in the aneurism. It covers the inner wall either partially or completely, being in the latter case perforated for arterial offshoots. This clot may occlude the artery, and it is not unfrequently continued into the arterial branches (peripherally) or into the aorta (centrally). Amongst the various changes that the clot undergoes, organisation of its outermost layer and softening are the most frequent. The constant occurrence of this clot is due to the presence of the worms, to the inflammation, ulcerative and regressive affection of the intima, and to the dilatation of the arterial tube. 8. The palisade worms are seldom absent from aneurisms of the horse. Their not being present is merely an accidental circumstance. On the average, nine palisade worms go to a verminous aneurism, and eleven in the horse. The highest number of worms found in one horse reached 121. Not unfre- quently, also, palisade worms, or their coverings in the form of larval skins, are found in the aneurismal walls. The immigra- tion and emigration of the palisade worms out of the intestine into the aneurism, and the reverse, take place probably, as a rule, within the arterial circulation. The path of the worm does not appear to be always the same, inasmuch as they can also wander through the peritoneal cavity. The worms found in the aneurismal walls are probably mostly only strayed specimens. 9. From a comparative pathologico-anatomical point of view, the developmental history of the aneurysma verminosum proves that a circumscribed endo-arteritis can determine the formation of an aneurism. 10. Like the worm-aneurism itself, atheroma of the abdo- minal arteries arises from a circumscribed acute and subacute endo-arteritis. The histological changes in the secondary atheroma of horses are perfectly analogous to those of the spontaneous atheroma of man. Idiopathic atheroma, as seen in man, does not occur any more in the horse than in the other SOLTDUNGULA 371 domestic animals. Atheroma in the horse is always secondary. To be sure, one observes an idiopathic chronic endo-arteritis in many abdominal arteries of the horse, which, however, never exhibits indications of atheromatous degeneration. 11. In consequence of its position the worm-aneurism of horses is not open to physical examination, and on that account cannot be diagnosed by physical signs ; moreover, it offers no characteristic symptoms. Its termination by rupture is extremely rare, the aneurisms of the abdominal aorta being more disposed to rupture than those of the anterior mesenteric artery. Of eighteen cases of known perforation, fifteen opened into the peritoneal cavity, and three into the bowel. The dangerous symptoms of' the worm-aneurism are exclusively due to embolism and thrombosis of the affected artery, arising from the parietal clot. The latter becomes especially dangerous through its increasing size and the softening which often accompanies it. The absorption and shrinking of this parietal clot, be it organised or not, is materially assisted by the high pressure to which it is exposed. 12. The very marked symptoms of vascular obstruction the sero-hsemorrhagic intestinal infarct in embolism and thrombosis of the mesentric arteries are easily explained by paralysis of the muscular coat of the intestine, by the absence or paucity of valves in the portal vein, by the readiness with which meteor- ismus (or flatus) arises, especially in herbivora, and by the loose consistence of the intestinal walls or villi. 13. The occlusion of the intestinal arteries, especially that arising suddenly, always has for its result a partial or complete paralysis of the portion of bowel which they supply. The palsy of the intestine causes the forward movement of the intestinal contents to cease, a stoppage of the faeces, a hin- drance to the discharge of faeces and gas, and also that exceed- ingly dangerous formation of gas (within the intestinal tract) which in the herbivora is so abnormal, both quantitatively and qualitatively. 14. In embolism and thrombosis of the mesenteric arteries ihe symptoms during life are entirely identical with those observed in the so-called colic of horses, as has been determined by numerous observations. The partial paralysis of the bowel, which is brought on by the embolism and thrombosis of the mesenteric arteries, forms in great part the chief and leading feature of the series of symptoms known as the " colic " of 372 PARASITES OF ANIMALS horses. The palsy of the bowel which arises in this way may explain also the frequent ruptures of the digestive canal and the greater number of its changes in position. The latter are specially favored by the structure of the abdominal viscera in the horse. 15. The old changes which one finds in the peripheral branches of the anterior mesenteric artery, in the form of expired and partly absorbed embolic and thrombolic processes (pigmentation, arterial and venous thrombi), particularly in connection with those arteries which are seats of the aneurism, decisively prove that the large majority of colics resulting in recovery, so far as they do not depend upon known injuries, are caused by paralysis of the bowel from embolism and thrombosis. The sudden occurrence, course, and result of these kinds of colics also testify to their embolic origin. 16. The oedematous, inflammatory, and hsemorrhagic pro- cesses that one often finds described as the cause of death in colic, almost exclusively depend on thrombosis and embolism of the mesenteric arteries, the cases forming about 40 to 50 per cent, of all fatal colics. 17. The rapid course in fatal colics, as well as the prepon- derating symptoms of dyspnoea in cases of recovery, is finally due to the abnormal development of gas in the alimentary canal. In addition to the diminution of the respiratory surface by the lofty position of the diaphragm, a direct gas-poisoning (carbonic acid and sulphuretted hydrogen) probably contributes to the intensity of the symptoms and the rapid course by diffusion of the abnormally developed gas out of the intestinal canal into the blood. 18. The variety of the anatomical derangements caused by embolism and thrombosis of the intestinal arteries is faithfully mirrored by the variety of the clinical symptoms and the different degrees in the intensity and course of the colic. 19. Amongst every 100 horses afflicted with internal disease, 40 are ill with colic. Among any hundred deceased horses 40 have perished from colic, and among 100 colic patients 87 recover and 13 die. The figures prove that neither amongst the epizootic nor sporadic diseases of horses is there any other affection which occurs so frequently, or claims anything like so many victims. Like the frequency of the worm-aneurism, the amount of disease and mortality increases with advancing age. The etiology of the colic of horses finds in the thrombosis and SOLIDUNGDLA 873 embolism of the mesenteric arteries, with the consequent paralysis of the bowel, an all-sufficient explanation, whilst the causes of colic hitherto accepted were for the most part insufficient. 20. In a great number of cases the thrombus of the worm- aneurism is continued past the mouth of the anterior mesenteric artery, into the lumen of the aorta, and, as such, is the exclusive cause of the embolisms of the pelvic and crural arteries which bring about the intermittent hobblings (the author says " intermit- terenden Hinken," not " Hahnentritten," the usual equivalent term for stringhalt). Considering the excessive frequency of the thrombus being continued into the aorta, it becomes highly probable that a great part of the diseases and lameness of the posterior extremities (" Hiift und Kreuzlahme, unsichtbarer Spath, &c./" which may be rendered " sciatic and hip or spinal lameness, obscure spavin, &c.") are due to occlusion of the arteries. 21. Owing to the fibrous thickening of the connective tissue of the root of the anterior mesenteric round the aneurism, and to the considerable size of the latter, disturbances of the inner- vation of the intestine, (as well as) hindrances to the passage of the chyle, and irregularities in the portal circulation may be created, which may well lie at the root of many chronic dis- turbances of digestion in horses. 22. Considering the great losses and heavy social disad- vantages that are occasioned by the colic of horses to the horse-breeder, to agriculture, and to the general welfare, it is of the highest importance to discover means which should prevent the introduction of the embryos with the food, and, as a consequence, the migration of the palisade worms into the mesenteric arteries of the horse. I wish it to be distinctly understood that the above summary is translated from Bellinger (Die Kolik s. 257). Instructive cases have been recorded both at home and abroad. Prof. Yarnell has remarked that "foals and yearlings suffer more from parasites in the paddocks than they do on adjoining farms where only a few animals are bred." This is explained by the relatively greater amount of egg-dispersion proceeding from the infected brood-mares. It is quite evident that the lives of many valuable animals are annually sacrificed by the neglect of hygienic arrangements. The palisade worm is chiefly destruc- tive to young animals, and as Mr. Percivall has well remarked, these parasites are " commonly the cause of lingering and hidden 374 PARASITES OF ANIMALS disease, terminating in death," without any suspicion on the part of the practitioner as to the nature of the malady. Instructive cases of this form of helminthiasis are given by Messrs Littler, Wyer, Harris, Meyrick, Litt, Percivall, Tindal, Walters, Brett, Aitken, Mead, Clancy, Baird, Mercer, Wright, Seaman, Hepburn, and others. Second only in clinical importance is the little four-spined strongyle (8. tetracanthus) . The sexes, often seen united, are nearly of equal size, the largest females reaching nearly ". They infest the caecum and colon, and have been found in all varieties of the horse, ass, and mule. The worm occurs in immense numbers and is a true blood-sucker. Its presence occasions severe colic and other violent symptoms, often proving fatal to the bearer. As already announced, in connection with my account of the tapeworms of the horse, this little worm may produce a virulent epidemic (epizooty). In the sexually - immature state the worm occu- pies the walls of the large intes- tine, where it gives rise to con- gestion, ecchymosis, inflamma- tion, and the formation of pus deposits. The species is readily recognised by its bright red color, by the four conical spines surrounding the mouth, by the FIG. 63. Larvae of Strongylus tetracanthus. a, two neck-bristles, and by the of the intestine (natural size); , * from the walls 4, the same (enlarged) ;*, an injury ; c, younfjer long three-lobed hood of the specimen (m sit*} ; d, the same (enlarged). Ori- . g lual - male, the posterior three- cleft ray having a rudimentary or fourth branch attached to its outer edge. In some specimens sent to me by Mr Whitney, I found this supplementary process fully twice as long as Schneider has represented it. From the earliest times this entozoon has been confounded with the palisade worm. Rudolphi and several of his successors, and also in recent times Ercolani and Colin, regarded this worm as the progeny of Strongylus armatus. During my earlier examinations I likewise fell into the error of describing the immature worm as representing a new species. The parasites described by me as Trichonemes (T. arcuata) were identical with those which Prof. Dick had previously described as " worms at different stages of growth," in his MS. sent to Dr Knox, 1836. Parasites of this kind were described by Dr SOLTDUNGULA 375 Knox as " Animals similar to Trichina; 9 ' by Diesing as the " Nematoideum equi caballi ;" by Mr. Littler as " Extremely small ascarides," in a letter to Mr Yarnell ; by Mr Varnell himself as " Entozoa in various stages of growth " and by Prof. Williams as " Entozoa from the intestinal walls/ ' in a letter to myself, dated March 13th, 1873. In reference, however, to Mr VarnelFs account of Mr Littler' s specimens I may observe that the appearances which he at first merely described as " blood spots/' he afterwards characterised as dark points "containing young worms in various stages of growth." As regards the course of development of this worm we have yet much to learn. Although the worm is a frequent cause of epizooty in this country it appears to be but little known on the Continent. Krabbe makes no mention of the helminthiasis set up by the four-spined strongyle, but he points out that the young occupy the mucous membrane, in which situation they lie coiled so as to present to the naked eye the appearance of little dark spots (Husdyrenes Indvoldsorme, 1872, p. 17, ' Aftryk. af Tidsskr. for Vet/). However, Leuckart's account of the appearances presented in a case brought under his notice is instructive. He writes : " I have hitherto had only a single opportunity of examining the strongyle capsules in the intestinal membrane of the horse. Their presence is limited to the caecum and colon, but they are so abundant in this situation that their numbers may be estimated by many hundreds. It was thus likewise in the case in question, the investigation of which by myself was rendered possible through the friendliness of Prof. Haubner of Dresden. The capsules were of oval form, and glimmered through the mucous membrane as opaque spota, mostly from one to three millimetres in size. In several of these capsules nothing was found beyond a greasy mass of a brownish color, which might readily be taken for a tuberculous substance ; but the greater number of them contained a coiled worm, from three to six millimetres long, their breadth being 0-15 to 0-26 mm. (which is ^' to "). They exhibited a highly colored stout intestine, and a thick-walled oral capsule of 0'022 mm. in depth and 0*025 mm. in breadth. On the dorsal side two three-cornered chitinous lamellae arise from the shallow floor of the small oral capsule. The cuticle, notwithstanding its firm structure, was still destitute of annulations. The tail (0'15 to 0*18 mm. in length) was strongly marked off from the 376 PARASITES OF ANIMALS rest of the body, being of a slender cylindrical form with a rounded-off extremity. The development of the sexual apparatus had not yet commenced. Notwithstanding the great differences of size presented by the body, the structure of all examples was exactly the same to the minutest particular, without exception. Also the smallest specimens, which scarcely measured one milli- metre, found in capsules of 0*3 mm. in diameter, were distinguish- able only by the absence of the oral cup, whose position was represented by a slender and thickened chitinous cylinder, as obtains in the earliest parasitic juvenile condition of Dochmius trigonocephalus. The transformation to the form presenting an oral cup occurs through a moulting, which is accomplished already in examples of 1'5 mm. in diameter. Later, also, the worms cast their skins in their capsules, without, however, changing the oral cup. In regard to the final purpose of this metamorphosis, my investigations have left me entirely in the lurch ; nevertheless, I do not entertain the smallest doubt that the worms which I have here described are the larval forms of Strongylus tetr acanthus." From numerous examinations I have satisfied myself that the worms after escaping the walls of the intestine and they may often be observed in the very act of passing re-enter the lumen of the bowel to undergo another change of skin prior to acquiring the adult state. This they accom- plish by rolling themselves within the faecal matter of the horse's intestine. The best examples I have seen of this phenomenon occurred in a case for the clinical particulars of which I am indebted to Mr Cawthron. Most interesting was it to notice these immature worms, each coiled within a sort of cocoon, which Mr Cawthron termed a cyst. All the forty little cocoons more or less resembled pills, the bright red color of their contained worms strongly contrasting with the FIG. 64.-F^n y sts or pellets con- dark color of the cocoons. They con- sisted of compressed debris, which under the microscope showed many common forms of vegetable hairs and paren- chyma, besides raphides and chlorophyll-granules. Internally, there was a cavity corresponding with the shape of the worm. In one instance I noticed that the worm had nearly completed SOLTDUNGULA 377 its ecdysis, a portion of the old skin still remaining attached to the tail. As already remarked, the evidence respecting the frequency and destructiveness of this little worm in England is now quite overwhelming. In a series of papers contributed to the e Vete- rinarian ' (too long for full quotation here), I have endea- voured to do justice to the " finds " and observations of those members of the veterinary profession who were good enough to supply me with valuable notes and communications. In parti- cular must my indebtedness to Mr Rees Lloyd be acknowledged, for, as previously observed, he it was who first recognised the parasitic character of the Welsh epizootic outbreaks. In the Deangunid and Talybont districts these strongyles proved terribly fatal to mountain ponies. It appears that the owners of the animals, as soon as they perceived anything amiss, at once disposed of them by sale, evidently anticipating fatal results sooner or later. The facts connected with some of the isolated cases brought under Mr Lloyd's care are especially interesting, as showing the virulence of the symptoms set up. Thus on the 9th of Feb., 1875, some time after I had identified the species from specimens he had sent me, Mr Lloyd writes as follows : " The last case I had was one which had been sold in this way, and which had suffered now and then from colicky pains for the space of about two months. The animal had been drenched with febrifuges and rubbed with stimulating liniments about the throat. However, I was sent for one evening, about an hour before the patient's death. I soon diagnosed the case as parasitic, and at the same time considered it to be a hopeless one. I remained with it the whole of the time, of which about forty- five minutes of the most acute pain was borne by the trembling beast, which was leaping, rolling, and tossing itself about with astonishing rapidity. The bulging eyes, gnashing teeth, foaming mouth, and sharp peculiar hoarseness, were pitiable to behold; when suddenly all was silent, he quietly rose to his feet, and nipped the grass as if nought had troubled him. I then trotted him quietly up a few yards of rising ground in the corner of the field, when he immediately got down to rise no more. The next day I examined him, and found myriads of the four-spined strongyles, a large number being encysted." Mr Rees Lloyd's account of this case is so graphic that I have reproduced it without abridgment. Speaking of another patient, a mare, he says, 378 PARASITES OF ANIMALS " she had voided thousands of these parasites, and was in a frightfully emaciated condition, but beyond a craving appetite there was little else to be noticed." Notwithstanding the few diagnostic indications afforded, Mr Lloyd, being led by the history of the case to suspect worms, at once examined the faeces, when he discovered thousands of these minute nematodes. Clinically, these facts ought not to be lost sight of. In addition to Mr Lloyd's cases I have received valuable particulars of others at the hands of Prof. Williams, Messrs Cawthron, A. Clarke, T. Gerrard, D. M. Storrar, and J. W. Whitney. Practically, it is important to inform the persons most in- terested that an active " drench " may be serviceable in dislodg- ing the free intestinal worms, but the administration of purga- tives must not be persevered in. As in the somewhat parallel case of Trichinosis in the human subject, the fatality of the disorder depends not upon the free and mature worms, but upon the migrating and sexually-immature forms. All attempts by means of active drugs to poison the entozoa, when once they have gained access to the tissues (whether actually capsuled or not), are worse than useless. By all means let the animals have a dose of aloes in the first instance, followed by warm bran mashes ; but thereafter let every care be taken to support the patient's strength. Especially should the exhibition of turpen- tine be avoided. Without doubt the cause of this, as of other similar epidemics, is primarily referable to atmospheric conditions which favor the multiplication of parasites. As the practical man cannot alter these climatal changes, he must do his best to check the disorder by removing the victims to new localities ; or, if the animals must remain in infected districts, by supplying them with various kinds of artificially prepared fodder, supple- mented by carefully filtered water. In this way, I believe, epidemics may be arrested, but they cannot be stamped out altogether, except by the adoption of measures which would be alike impracticable and unwarrantable. Passing to the consideration of other intestinal nematodes, the next in importance is the large lumbricoid (Ascaris megaloce- phala) found in all solipeds, including the zebra. Whilst the male worms rarely exceed seven inches in length, the females sometimes reach seventeen inches. Science is indebted to Schneider for setting at rest all doubt as to the specific dis- tinctness of this worm. The far larger number of caudal papillae at once distinguishes it from the lumbricoid of man and the SOLIDUNGULA 379 hog. The equine Ascaris may occur in any part of the alimen- tary canal, but the small gut forms its proper head- quarters. The entire course of development of this worm has not been traced ; nevertheless, Heller found human lumbricoids measur- ing less than the eighth of an inch. It is not likely that any intermediate host is necessary for the growth of the larvae, prior to their access to the definitive host. I have reared the larvae in impure water and in moist horse- dung, up to the size of ~ of an inch. They were then furnished with a completely-formed digestive apparatus. Davaine kept the intra-chorional embryos alive in water for five or six years. His experiments on rats, dogs, and on a cow, led to no decisive results ; but it is impor- tant to know that the eggs of lumbricoids effectually resist dryness. According to Davaine, however, embryonal develop- ment is thus arrested (except in Ascaris tetraptera of the mouse). Seeing how readily the most ordinary attention to cleanliness must suffice to prevent lumbricoid helminthism, it is scandalous that so many severe cases of disease from this source should ever and anon turn up and be reported. In no properly con- ducted stable are these large entozoa ever to be seen in any considerable numbers ; for so long as the water-supply is good and the fodder clean there is no possibility of infection. A fertile source of infection, however, results from allowing horses to drink at foul road-side ponds and from open waters in the vicinity of stables and paddocks where foals are reared. Into the clinical bearings of the subject I do not enter, but a host of interesting records of lumbricoid disease may be found in veterinary journals, both home and foreign. These have their counterpart in the very similar cases recorded in the medical journals, and quoted by me in the 34th bibliography of this work. From Sonsino's report these worms do not appear very common in Egypt, but the veterinary inspector, Dr Zunhinett, had occasionally met with them. From Messrs W. Awde, J. B. Wolstenholme, and other English veterinary surgeons, I have received notes of interesting cases, but in this connec- tion I can only further refer to the published cases of Messrs Anderson, Boddington, Cartwright, Harrison, Moir, and Wallis. The French cases, by M. Cambron and by M. Yeret, are par- ticularly instructive. Many of the cases give fatal results. In one fatal instance a pupil of mine counted over 1200 of these worms, and in a similar fatal case Mr Lewis reports that 380 . PARASITES OF ANIMALS he found the small intestine literally crammed, some thousands of worms being huddled together in large masses. The next nematode of general interest is the pinworm (Oxyuris curvula). Professional men often confound it with the palisade worm, and it has even been mistaken for the rat- tail maggot (Helophilus) . The longest males measure If", and the females often beyond 4 inches. This worm infests the colon in great numbers, the species being easily recognised by its long subulate tail. Like its much smaller congener infest- ing man, this worm occasions severe local irritation, clusters of the eggs often accumulating to form yellow incrustations at the FIG. 65. Head of Oryur'u curvula. Highly magnified. After Bask. verge of the anus. Equine pin worms are vegetable feeders, and, like human Oxyurides, are conveyed to the bearer in a direct manner. No horse properly looked after can be infested by these worms. Local washings and stable cleanliness being secured by an attentive groom, the animals are safe. Prophy- lactic measures of this kind are all-powerful against infection. Notwithstanding the ease, however, with which the oxyuris disorder may both be prevented and cured, we find it prevails extensively everywhere, alike in mankind and in solipeds. Dr Sonsino found these parasites abundant in Egypt, some of the worms reaching a length of nearly five inches (120 mm.). Mr Emmerson has given an interesting account of the prejudicial effects of these entozoa in the horses of Singapore. One of the most remarkable equine parasites is that which I am in the habit of calling the large-mouthed maw- worm (Spi- roptera megastoma], in centra-distinction to the small-mouthed species (8. microstoma). In this country the worm has attracted little notice, but through the kindness of Mr Spooner SOLIDUNGULA. 381 Hart, of Calcutta, and of Mr Percivall, of the llth Hussars, stationed at Umballa, I have had abundant opportunities of examining this entozoon and the singular pathological appear- ances which it occasions. This parasite was first described by Rudolphi, who says : " Spiroptera capitis discreti ore magno nudo, cauda feminae rectiuscula acuta, mavis simpliciter spirali, corpusculis rotundis ad basim penis styliformis." The worm was afterwards observed by Schultze, Chabert, and frequently also by Andral, but the best accounts of it are those given by Gurlt, Valenciennes, and Dujardin. Schneider has likewise done much to set at rest disputed points. Respecting the Spiroptere du Cheval, Dujardin, writing in 1844, observes that " Rudolphi at first studied this helminth from examples found in great number by Reckleben, at Berlin, in tubercles of the stomach of two horses. Quite recently, M. Valenciennes, at Paris, has found it frequently in tumours, from twenty to forty millimetres in size, in the stomach of eleven horses out of twenty-five that he had subjected to this kind of research. These tumours, lodged between the mucous and muscular layers of the digestive canal, are perforated by several holes travers- ing the mucous membrane. They are divided internally by a number of folds into numerous intercommunicating cavities, and sometimes filled with solid mucus and very many spirop- teras. It is from examples collected by M. Valenciennes that I have been able to study the parasite." As regards the description of the worm, it is almost needless to say that Dujardin's account is minute and admirable in all respects. In fact, no naturalist ever exceeded the Rennes savant in carefulness and accuracy of detail. An interesting point con- nected with these stomach-worms lies in the circumstance that Gurlt recognised two varieties, one of which he termed Sp. meg., var. major. It remained for Schneider to show that the larger worms formed an altogether distinct species, which he termed Filaria microstoma (' Monogr./ 1. c., 1866, s. 98). It was not unnatural that Rudolphi and his successors should confound these two forms together, and it is also not a little curious that the smaller of the two species has the larger mouth. Practically, veterinarians will probably rest content to know that whilst the Spiroptera megastoma occupies tumours in the walls of the stomach, the S. microstoma is always to be found free in the cavity of that organ. Any helminthologist who may chance to have read the Ceylon Company's report on the 382 PARASITES OF ANIMALS fatal epidemic affecting the mules of the Mauritius in 1876 can scarcely fail to have observed that the worm called Ascaris vermicular is by Mr Bradshaw is none other than our Sp. megastoma. The description of the tumours as " reticulated " sufficiently explains their honeycomb- like appearance, but I think that the expression "alveolar" would better convey their true pathological character. Mr Spooner Hart compared these structures, which he terms " abodes," to mole-hills, but there is no good ground for supposing that the wanderings of the parasites are in any sense comparable to the burrowings of the mole. In like manner the expression " nidus," employed by Mr Bradshaw, though suggestive of their nest-like appearance, is to some extent misleading, as it implies that the worms form a nide or brood. Possibly, it may turn out that all the nema- todes in each tumour have been bred in the spot where they are found, but hitherto they have only been seen in the adult state. Earlier stages of growth should be diligently sought for. Widely dissimilar as the two maw-worms are, it would not greatly surprise me to learn that Sp. megastoma and 8. micro- stoma are dimorphic conditions of one and the same entozoon. At all events, Ercolani's determination of the relations subsist- ing between Ascaris inflexa and A. vesicularis suggests a possible analogy of this kind. I may mention that the male Spiroptera megastoma reaches nearly one third and the female one half of an inch in length. A constriction separates the head from the body. The mouth is surrounded by four thick horny lips, the dorso-ventral pair being the larger. The tail of the male is spirally twisted, and furnished with lateral bands supported by three or four ribs. It carries two curved spicules of unequal size. There are five pairs of caudal papillae, the tail being bluntly pointed in both sexes. The vulva of the female is placed about i" below the head. The eggs are linear or very narrow, and furnished with thick shells. According to Sonsino, who found Sp. megastoma in five out of sixteen Egyptian horses, the verminiferous growths are usually seated near the pyloric end of the stomach, as many as four tumours occurring at one time. Neither Sonsino nor any other observers already quoted appear to think that these morbid changes in any way interfere with the healthy performance of the gastric functions. However, I am of opinion that at least one recorded fatal case of parasitism, producing rupture of the stomach, affords an instance, however rare, of the injurious SOLIDUNGULA 383 action of this entozoon. It is reported under the signature of " Argus/' quoted below. In this connection I may mention that in 1864 Prof. Axe observed some small worms, scarcely visible to the naked eye, in the mucous membrane of the stomach of a donkey, the same worms being subsequently observed in three other donkeys brought to the dissecting room of the Royal Veterinary College. From the examination of a drawing of one of the male worms, executed by Prof. Simonds, I am led to believe that the parasites are entirely new to science. The hood being well marked there can be no doubt as to the strongyloid affinities of the worm. I therefore propose to call the worm after its discoverer (Strongylus Axei). In regard to Sp. microstoma, the males measure up to f", whilst the females have a long diameter of |" or rather more (10'"). The small- mouthed maw-worm lives free in the stomach, and, as Krabbe observes, not unfrequently in very considerable numbers. It does not appear to be capable of injuring the host. One of the most interesting equine nematodes is the eye- worm. Most veterinary writers speak of it as the Filaria oculi, but to helminthologists it is better known by the more correct designation, F. papillosa. Though commonly obtained from the eyeball and its tunics, the worm infests various tissues and organs of the body, being found in the thorax, abdomen, mem- branes of the brain, muscles, and cellular tissues. It infests the ass and mule, and also horned ruminants. The males attain a length of three inches and the females seven inches. The head is broad, with a gaping mouth armed with a ring of chitine and two prominent denticles. There are also two papillae on the neck near the middle line, besides sixteen caudal papillae, eight on either side. The tail of the male is spirally twisted, that of the female only slightly curved. Notwithstanding the many opportunities afforded of examining this parasite in the fresh state, very little is known respecting its origin and course of development. Dr Manson, who found that the mouth was armed with a five- or six-toothed oral saw, considers that the eye is not a proper resting place for the parasite, and that when one wandering worm comes across the track of another it follows it up from sexual instinct, and thus several may be found together in one place. The tracks are readily seen by the naked eye. Dr Sonsino speaks of it as a " yellow line." This Italian observer found the worm in twelve 384 PARASITES OF ANIMALS out of the sixteen solipeds he examined during the plague. Each horse showed from two to a dozen worms " in the peri- toneal cavity, wandering free on the serous lining, without causing any apparent mischief to the membrane." On one occasion Sonsino found the worm in the liver. From the similarity of habit there can be little doubt that the cases of guinea- worm (F. medinensis) recorded by Clark son and others, as occurring in the horse, were merely examples of F. papillosa. I think so all the more because the lamented Fed- schenko verbally expressed to me his astonishment that I had in my introductory treatise (p. 387) spoken of the Dracunculus as an equine parasite. I did so on the authority of others. To the Rev. Horace Waller I am indebted for specimens of the eye-worm brought from Assam, and to Mr Spooner Hart for others sent from India. For examples occurring in England I am indebted to Mr Hay don Leggett, who, in 1875, sent me three specimens extracted from the eye of a five-year-old mare. Mr Steel has also given me an example of F. papillosa taken from the peritoneum of a donkey. Similar cases are constantly occurring in the practice of veterinarians in Hindostan. Highly interesting Indian cases are recorded by Kennedy, Molyneux, Twining, and Breton, and in addition to these I may also par- ticularise those of Macnamara, C. Percivall, Hickman, Clarkson, Skeavington, and Jeaffreson. The cases by Lee and Grellier also deserve attention. Another species of thread-worm (Filaria lacrymalis) is occa- sionally found in the horse between the lids and eyeball. It is a comparatively small and harmless parasite, the males measur- ing J'' i n length and the females '' '. It also infests the ox. Both the large and small eye-worms are viviparous, and, not improbably, both of them are the means of conveying embryonic Filariae into the circulation. Be this as it may, we owe to Dr Sonsino the discovery of haematozoa in an Egyptian horse. The larval worm was provisionally named by him Filaria san- guinis equi. The microscopic nematodes closely resemble the larvae of F. sanguirds hominis, but they are smaller. The horse from whose blood Dr Sonsino obtained the minute worms was also found, by post-mortem examination, to have been infested by Filaria papillosa, a circumstance which naturally suggested a genetic relation between the larval and adult parasites. Similar, if not the same, microscopic worms had been previously discovered by Wedl, who primarily and independently regarded SOLIDUNGULA 385 them as embryos of F. papillosa. Another curious filaria-like entozoon is the reticulated threadworm (Onchocerca reticulata). In England we have no acquaintance with this singular parasite, but it appears to be tolerably common in Italy. Excellent figures of it have been given by Diesing. Both males and females are in the habit of coiling themselves within the muscles, where they are found invested by a capsule of connective tissue. When unrolled the sexes are found of equal size, acquiring a length of 14". The worm has a simple unarmed mouth, its body being marked by a series of annulations formed of incom- pletely anastomosing rings. It does not appear to possess any clinical importance. In connection with the equine nematodes I need only mention the lung- worm (Strongylus micrurus). Its importance in relation to the production of husk or parasitic bronchitis in calves has already been considered. The worm is rarely productive of mischief amongst solipeds, nevertheless, in the dissecting-room subjects at the Royal Veterinary College, the presence of these parasites in the lungs is frequently noticed. Lastly, it only remains for me to observe that the renal strongyle (8. gigas) is occasionally seen in the horse. In 1792 M. Chabert found one in the left kidney, and similar cases have since either been witnessed or reported by Rudolphi and Leblanc. Of the numerous insect parasites and tormentors of solipeds the gadflies (CEstridce) demand chief attention. For special description of the forms, Brauer's monograph is the most, and, in fact, the only reliable authority. Here it is not possible to give the characters of the various equine species, of which at least half a dozen are known to science. As remarked by me in the special chapter contributed to Prof. Williams' well-known veterinary treatise, the common gad-fly (Gastrophilus equi) attacks the animal whilst grazing late in the summer, its object being, not to derive sustenance, but to deposit its eggs. This it accomplishes by means of a glutinous excretion, causing the ova to adhere to the hairs. The parts selected are chiefly those of the shoulder, base of the neck, and inner part of the fore legs, especially about the knees, for in these situations the horse will have no difficulty in reaching the ova with its tongue. When the animal licks those parts of the coat where the eggs have been placed, the moisture of the tongue, aided by warmth, hatches the ova, and in something less than three weeks from the time of the deposition of the eggs, the larvae make their 25 386 PARASITES OF ANIMALS escape. As maggots they are next transferred to the mouth, and ultimately to the stomach along with food and drink. A great many larvae perish during this passive mode of immigra- tion, some being dropped from the mouth, and others being crushed in the fodder during mastication. It has been calcu- lated that out of the many hundreds of eggs deposited on a single horse, scarcely one out of fifty of the larvae arrive within the stomach. Notwithstanding this waste the interior of the stomach may become completely covered with " bots." Whether there be few or many, they are anchored in this situation chiefly by means of two large cephalic hooks. After the bots have attained perfect growth they voluntarily loosen their hold, and allow themselves to be carried along the alimentary canal until they escape with the faeces. Many persons suppose that during their passage through the intestinal canal they re-attach themselves to the mucous membrane, thereby occasioning severe intestinal irritation. This is an error. In all cases they sooner or later fall to the ground, and when transferred to the soil they bury themselves beneath the surface, in order to undergo transformation into the pupa condition. Having remained in the earth for a period of six or seven weeks they finally emerge from their pupal-cocoons as perfect dipterous insects. It thus appears that bots ordinarily pass about eight months of their lifetime in the digestive organs of the horse. That they are capable of giving rise to severe disease there can be no doubt, but it is not often that the disorder is correctly diagnosed, since it is only by the passage of the larvae that the practitioner can be made aware of their presence. Mr J. S. Wood has published a case of tetanus in a mare, associated with the larvae of (Estrus equi, and Mr J. T. Brewer has also given a case where the duodenum was perforated by bots. Mr Goodworth records an instance of pyloric obstruction from the same cause, and Mr W. Coupe informed me in 187G that he had a drove of foreign ponies under his care, all of which suffered irritation from haemorrhoidal bots. He removed them with a pair of forceps. Although frequently said to do so, the common bot does not attach itself to the rectum before finally escaping the host. The larvae of G. hamorrhoidalis normally reside there. In this situation they seriously inconvenience the bearer. The bots of G. nasalis are often confounded with those which ordinarily occupy the stomach of the bearer. The larvae of G. nasalis commonly reside in the duodenum near the pylorus. SOLIDUNGULA 387 According to Schwab and Brauer, they rarely occupy the stomach. As occurs in the common species, this bot passes away with the faeces, and does not attach itself to the lower bowel. The bots of Brauer's G. inermis much resemble those of G. equi, but they are much smaller and attach themselves to the wall of the small intestine. The bots of G. pecorum, which dwell in the rectum, are readily recognised by their peculiar form and scanty spination. They are pointed in front and truncated posteriorly. An assinine variety of G. equi has been described by Bilharz, whilst another distinct species (G. flavipes) attacks the ass and mule. The bot-larvae of the latter host require recognition and description. A great variety of other equine bot-flies have been described, but all, or nearly all, of them are mere synonyms of the above-men- tioned forms. For the limitation of the species I accept Brauer's authority, and likewise his nomenclature. A great deal of nonsense has been written respecting bots. It is a relief to believe that G. (CEstrus) veterinus, G. ferruginatus, G. jubarum, G. (CE.) Clarkii, G. salutiferus, G. subjacens, and many others, are not good species, at least that they are mere synonyms. In regard to the occurrence of subcutaneous bot- like maggots in the horse and ass, no doubt need exist on this point. I am indebted to Mr Percy Gregory for characteristic specimens taken from the back, neck, and withers of a four-year- old gelding. They appear to correspond with the Hypoderma Loiseti of Joly. Similar maggots have been found in the ass by Herr Erber, but Brauer refers these to H. silenus. Prof. Briick- muller published a case where the brain was infested by larvae ; and Mr Shipley has sent me an example of H. equi, which he states he removed from the choroid plexus of the brain. In ad- dition to the cases by Woods, Goodworth, and Brewer, already quoted, others have been published by Tyndal and Cartwright. Amongst the numerous other parasitic dipterous larvae one must notice the rat-tailed maggots (Helophilus). A genuine instance of this kind has been brought under my observation, but the example recorded by Professor Axe was spurious. Professor Simonds and myself saw this supposed maggot, which was merely a very stout and pregnant Oxyuris curvula. Another genuine case was published by Mr. Stanley. This is quoted by A Numan in his essay on Canurus. I have previously mentioned my having received an Helophilus-larva that had passed from the human body. One of the most troublesome 388 PARASITES OF ANIMALS external parasites is the so-called horse-tick or forest-fly (Hippobosca equina). They attack the abdomen, flanks, and inner part of the thighs in great numbers, occasioning great distress to the bearer. Being of leathery toughness their bodies are not easily crushed, and they are removed only with great difficulty. There is an equine disease in Sweden called Staclcra, which is erroneously attributed to injuries produced by a species of fly-maggot (Lixus) which lives on the fine-leaved water-drop wort (Phellandrium) . As regards the so-called free parasites, or rather non-parasitic obnoxious insects, which torment solipeds, it is impossible even to enumerate them. The tsetse of South Africa (Olossina morsitans) is terribly fatal to the horse, but it is said that the mule, ass, and zebra do not suffer from its bites an immunity shared by swine, goats, antelopes, and man himself. Major Vardon's rash experiment (based on the supposition that horses deprived of fresh green food would not suffer from the attacks of the fly) proved fatal to an animal which he purposely exposed* on a much infested hill-top. The horse died ten days after it was bitten. According to Chapman, the bites of four tsetse flies are sufficient to kill an ox, but in man the irritation produced is very slight. Amongst other insects proving troublesome to solipeds may be mentioned the leg-sticker (Stomoxys calcitrans) , the clegg (Hamatopota pluvialis) which is very abundant in the West Highlands, various species of Tabanidae and Asilidce (Tabanus autumnalis, T. bovinus, CJtrysops cacutiens, Asilus crabroniformis) , and also a host of ordinary flies and gnats (MuscidcB and Tipulida), as, for example, Anthomyia meteorica and Culex equinus. In India the bite of a species of Simulia gives rise to the formation of open sores of the most intractable character. As regards hemipterous insects it may be said that many species of lice (Anoplurd) produce what is called phthiriasis or lousiness in the horse, some of them being derived from poultry. The best known species are Trichodectes equi, T. scalaris, Hcematopinus equi, H. vituli, H. eurysternus, and the ass r louse (H. asini). Of the half dozen or more species infesting the hen (belonging to the genera Goniocotes, Liotheum, &c.) it is not probable that more than one or, at most, two of them are concerned in the production of poultry-lousiness in the horse. As an equine disorder this kind of phthiriasis was first described by Bouley. Cases in England have been observed by Messrs. Henderson, Moore, and Woodger. For some SOLIDUNGULA 389 account of cases of lousiness due to Hcematopinus I am indebted to Mr S. Butters. As regards the scab, itch, and mange insects or mites (Acaridce), three perfectly distinct forms are known. Adopting M. Megnin's classification they are Scar- coptes scabiei, var. equi, Psoroptes longirostris, var. equi (being the Dermatodectes equi of Grerlach), and Chorioptes spathiferus, var. cqui, which is the Symbiotes equi of Gerlach. All the species have been beautifully illustrated by M. Megnin, whose memoir has dispersed many of the clouds of error and mis- representation which have hitherto surrounded the subject. Whilst Psoroptes forms the true horse-mite, and attacks various parts of the body, Chorioptes confines its attacks to the posterior regions. Messrs South and Day and myself have verified some of the facts recorded by Megnin in respect of the struc- ture and habits of this last species. Another kind of mite (Glyciphagus hippopodos) is stated to infest the ulcerated feet of horses. It would appear that no true ticks properly belong to solipeds ; nevertheless, the common cattle-tick (Ixodes bovis) occasionally attacks horses. Probably several other species of IxodidsB, known to infest other animals, behave in the same way. The Arachnidan called Pentastoma tcenioides, though properly belonging to the dog, has on several occasions been detected in the nasal or frontal 'sinuses of the horse. Such instances are recorded by Chabert and Greve. The largest example of this singular entozoon seen by myself was obtained from the same situation, and presented to me by the late Mr C. B. Eose, whose writings I have frequently quoted in connection with the Coenuri of rabbits. BIBLIOGRAPHY (No. 50). Aitken, /., " Worms in the Sper- matic Artery of a Colt," ' Veterinarian/ p. 683, 1855. Ander- son, J.j "A Case of Strangulation of the Ileum (with Lumbrici)," 'Veterinarian/ p. 261, 1859. (Anonymous), " Eupture of the Stomach, associated with the existence of Cysts between its Coats containing Worms/ 7 ' Veterinarian/ March, 1864, p. 151. (Anon.), " Extraction of Filaria oculi from the Horse," by "Miles," ' Veterinarian/ 1864, p. 218. (Anon.), "Case of F. oculi in the Horse," ( Veterinarian, 7 1864, p. 218. (Anon.), " Worms in the Coats of the Stomach of a Horse," by "Argus," in the ' Veterinarian/ 1865, p. 151. Baird, W., "Notice of Sclerostoma in the Testicle of the Horse," ' Proc. Zool. Soc./ 1861. Blanchard, " Anoplocephala perfoliata," 'Ann. des Sci. Nat./ 3rd ser., torn, x, p. 345. Bollinger, 0., ' Die Kolik der 390 PARASITES OF -ANIMALS Pferde and das Wurmaneurisma der Eingeweidearterien/ Mun- chen, 1870. (Reviewed by myself in the ' Veterinarian/ Jan. April, 1874.) Bovett, " Existence of Filariaa in a Sinuous Ulcer of the Withers of a Mare/' 'Veterinarian/ p. 515, 1861. Bradshaiv, C., " Death of Mules from Parasitic Disease in the Mauritius (with remarks by Dr Cobbold)," ' Veterinarian/ Dec., 1876, p. 837.Brauer, F., ' Monographie der CEstriden/ Wien, 1863. Idem, " (Estr. (Hypoderma) Clarkii," in 'Ver- handl. der zool.-bot. Gessellsch. in Wien/ xxv, p. 75. Idem, " On Cephenomyia trompe from the Reindeer," ibid., p. 77. Idem, " Hypoderma bonassi from the American Buffalo/' ibid. (all with figs.), 1875. Breton, "On the Worm found in the Eye of the Horse/' ' Calcutta Med. and Phys. Soc. Trans./ vol. i, 1825, p. 337. Brown, D. 8., " The (Esirus equi, or Horse-bot," the 'Veterinary Journal/ July, 1877, p. 14. Bruckmuller, " Larvas in the Brain of a Foal/' from ' Viert. fiir wissensch. Vet./ in 'Veterinarian/ p. 82, 1857. Cartwright, W. A., " On Strangulation of the Bowels, associated with about 150 Bots, and also some 150 Ascarides, in the Horse," 'Vete- rinarian/ p. 413, 1833. Idem, " Case of about 200 ' Bots in the (Esophagus ' of a Horse," ibid., p. 400, 1828. Chambron, " On a Parasitic Malady in the Horse," from ' Ann. de Med. Vet./ in ' Edin. Vet. Rev./" 1861 ; see also (Oambron) ' Vete- rinarian/ 1860, p. 612. Clark, B., " Obs. on the genus (Estrus," 'Linn. Trans./ vol. iii, p. 289, 1797. Idem, 'An Essay on the Bots of Horses and other Animals,' London, 1815. Clarkson, N. F., " Case of Filaria oculi in the Horse," 'Vet. Rec./ vol. i, p. 73, 1845. Idem, " Case of Filaria medinensis in the Horse," ibid., 184*5. Cobbold, " On the Diptera (bots)/' in a chap, on the Parasitic Diseases of Animals, in Williams' work (1. c., Bibl. No. 48). Idem, "Obs. on rare Parasites from the Horse," ' Vete- rinarian/ Feb., 1874. Idem, "Further remarks on rare Parasites from the Horse," ibid., April, 1874. Idem, "Fatal Epid. affecting Ponies," ibid., June, 1874. Idem,, " Remarks on Megnin's Tapeworm," ibid., Sept., 1874. Idem, " Report on Parasites (sent from India by F. F. Collins and Spooner Hart)/' ibid., Nov., 1874. Idem, " Epizooty in the Horse, more especially in relation to the Ravages produced by the Four-spined Strongyle (S. tetracanthus)," ibid., April, 1875. Idem, "The Egyptian Horse Plague in relation to the question of Parasitism," ibid., Nov., 1876. Idem, "Description of the new Equine Fluke (Gastrodiscus Sonsinoii}," ibid., April, 1877. Idem, " On SOLIDUNGULA 391 Worm-like Organisms within the Mitral Valve of a Horse/' ibid., 1877. Idem, "Entozoa of the Horse and Elephant" (see Bibl. No. 51). Idem, "Observations respecting the Large- mouthed Maw-worm of the Horse," ' Veterinarian/ Jan., 1877. Couchman, T., "Worms in the Kidney of a Colt," ' Veteri- narian/ p. 145, 1857. Coupe, W., "Fatal Parasitism in a Colt," ' Veterinarian/ Dec., 1876, p. 844. Davaine, "Les Cestoides," in ' Diet. Encycl. des Sci. Med./ p. 591. Dick (see Knox) . Dickens, G., ' Joint-lameness in Colts, associated with and symptomatic of Lumbricoid Worms," ' Veterinarian/ p. 601, 1863. Dun, R., " Eemarks on Entozoa of the Horse," ' Vete- rinarian/ 1854, p. 445. Dupuy (with M. Prince), " Filariaa in the Great Mesenteric of a Horse," ' Veterinarian/ 1835, p. 570. Emmerson, G., " Prevalence of Entozoa among Horses in the Island of Singapore/' 'Veterinarian/ 1861, p. 514. Friedberger, F., ' Die Kolik der Pferde/ Berlin, 1874. (Reviewed by me in the ' Veterinarian/ Jan. April, 1874.) Fry, " Case of Worms in the Horse," ' The Hippiatrist/ &c., vol. iii, p. 10, 1830. Gamgee, J. (senior), " On Bots," ' Edin. Vet. Rev./ July, 1858. Goodworth, S., " Obstruction of the Pyloric Orifice of the Stomach by Bots," ' Veterinarian/ p. 410, l837.Grellier, J., " On the Worm in the Eye (of the Horse)," ' Veterinarian/ p. 18, l8U.Harlan, R., " Case of a Colt killed by Worms," in his 'Med. and Phys. Researches/ p. 554; see also 'Med.- Chir. Rev./ 1836. Harris, "A Case of Worms in the Arteries of a Colt," ' Veterinarian/ p. 307, 1834. Harrison, J. D., "The singular effect of Worms in the Stomach of a Mare," ' Vete- rinarian/ p. 331, 1842. Hickman, T., " Worm in the Eye of the Horse," ' Edin. Vet. Rev./ 1864, p. 653.Hopkinson,F., " Account of a Worm in the Horse's Eye," from ' Trans, of Amer. Phil. Soc./ in f Med. Comment./ vol. xi, p. 166, 1784. Hutchinson, J., " Hydatid in the Eye of a Horse," ' Path. Soc. Trans./ and rep. in ' Lancet/ 1857. Huxley, " On Echinococcus (from the Zebra)," see Bibl. No. 20, o. Jea/reson, W., " Case of Removal of a Worm from the Eye of an Arab Horse," 'Lancet/ p. 690, 1836-37, and 'Veterinarian/ p. 471, 1837. Kennedy, M., " Account of a Nondescript Worm (Ascaris pel- lucidus) found in the Eyes of Horses in India," ' Trans. Roy. Soc. Edin./ vol. xi, p. 107, 1816. Kirkman, ' Hydatids ' (see Bibl. No. 20, o). Knox, 'Edin. Med. and Surg. Journ./ 1836. Krabbe (1. c., in text). Lee, G. A., "On Filaria papillosa in the Anterior Chamber of the Eye of a Horse (and on Filarise in 392 PAEAS1TES OF ANIMALS general, &c.)/' ' Amer. Journ. Sci. and Art./ vol. xxxix, p. 278, 1840. Lessona, G., "On the Bot (or CEstrus) of the Horse," from 'Recueil de Med. Vet./ in 'Veterinarian/ p. 156, 1854. Leuckart (1. c., in text) . Litt, W., " A Singular Case (of an immense number of Worms in a Colt)," ' Veterinarian,' p. 529, 1852. Macnamara, " On F. papillosa in the Eye of Man and the Horse," ' Indian Ann. Med. Sci./ 1864. Marcet (see Bibl. No. 34). Mead, J., "A Worm in the Scrotum of a Colt," ' Veterinarian/ 1 843, p. 648. Megnin, " Petit Tania inerme du Cheval," in ' Bull, de la Soc. Cent, de Med. Vet./ t. vi, 3e serie, p. 112. Idem, ' Monog. de la tribu des Sarcoptides/ &c. ; see also review by myself in the ' Veterinarian,' Aug., 1877. Mercer, J., " On Entozoal or Worm-aneurism," 'Lond. Med. Gaz./ 1847, and in part x of " Contrib. to Zool. Path.," in the ' Veterinarian/ p. 33, 1846. Meyrick, /., " Death of a Colt from Entozoa within the Abdomen," ' Veterinarian/ 1859, p. 695. Moir, J., "Rupture of the Ileum resulting from Worms," 'Veterinarian,' 1857, p. 265. Motyneux, R., " On Worm in the Eye of Horses in India," 'Veterinarian/ 1828, p. 309. Morgan, A., "Case of Hydatid in the Brain of a Mare," 'Veterinarian/ p. 396, 1855. Numan, A., ' Ueber die Bremsen Larven, im Magen der Pferde/ 1837. Idem, "Entozoon (Monostoma settenii) from the Eye of a Horse," from ' Tidschr. voor naturl. Geschied. en Physiol./ 1842, in 'Med.-Chir. Rev./ 1842. Idem (for remarks on Cysticercus fistularis) , 'Over den veelkop blaasworm' (1. c., Bibl. No. 49), p. 263. PeaM, T., "A Discourse on 'Worms/ " at p. 37, in his ' Observations, chiefly practical, on some of the more common Diseases of the Horse/ pub. at Cork, 1814. Percivall, G., "Worm in the Eye of the Horse (two cases)," ' Veterinarian,' p. 75, 1828. Percivall, J., " A Case of Ascarides in the large Intestines of the Horse," ' Veterinarian/ p. 858, 1829. Poulton, T. J., "Large numbers of Parasites in the Intestines of a Mare," ' Veterinarian/ 1866, p. 385. Seaman, J., "Worms in the Blood-vessels of Horses and Colts," ' Edin. Vet. Rev./ 1864, p. 520. Simonds, " On Disease of the Mesenteric Artery, produced by Strongyli," ' Path. Soc. Trans./ 1854. Skeavington, G., " On Worm in the Eye of the Horse (three cases)," 'Veterinarian/ 1834, p. 196. Sonsino, P., "On the Entozoa of the Horse in relation to the late Egyptian Equine Plague," 'Veterinarian/ Feb. and March, 1877. Tijndal, J., " Worms in the Intestines of a Mare," ' Veterinarian/ 1843, p. 629. Twining, W., " Obs. on the Filaria or Threadworm PACHYDERMATA 393 found in the Eyes of Horses in India/' ' Calcutta Med. and Phys. Soc. Trans./ vol. i, p. 345, 1825; rep. in 'Veterinarian/ p. 114, 1828. Valenciennes, " On the Spiroptera megastoma of Gurlt," abstract of a paper from Acad. Sci. of Paris, reported in ' Lancet/ 1843. Varnell, " Remarks on Cases of Parasitic Disease in Horses," ' Veterinarian/ p. 201, 1864. Veret, "Per- foration of the small Intestines by Ascarides lumbricoides (in the Horse)/' from ' Rec. de Med. Vet./ in ' Veterinarian/ p. 569, 1837. Vincent, " Curious case of Incurable Lameness from Hydatids," ' Veterinarian/ 1848, p. 674; see also p. 3, ibid. Wallis, " Note on the occurrence of (250) Lumbrici in a Horse/' ( Veterinary Record/ 1849, p. 300. Walters, E. G., "Parasites in the Kidneys of a Mare/' ' Veterinarian/ 1866, p. 265. Woodger, " Hydatid in the Brain of a Horse," 'Vete- rinarian/ 1863, p. 75. Woods, J. 8., " Tetanus in a Mare, associated with the Larvae of (Estrus equi within the Stomach and Duodenum/' 'Veterinarian/ 1859, p. 693. Wright, " Strongyli in the Scrotum of a Colt," ' Veterinary Record/ 1849, p. 385. Youatt, "Worms between the Tunics of the Stomach," 'Vete- rinarian/ 1835, p. 571. Idem, " Tetanus, Worms in the Trachea, and Dilatation of the Heart, in a Zebra," ibid., p. 504, 1836. Idem, " Worms' in the Nasal Cavity of the Horse," ibid., p. 329, 1832Zangger, "Remarks on Entozoa," from the French, 'Veterinarian/ 1855, p. 463. PAET X (PACHYDEEMATA) Concerning the parasites and parasitic diseases of this mis- cellaneous assemblage of large mammals, I shall first speak of those of the proboscideans (Elephantidse) . Except by myself, they have been but little studied, and I am yet waiting for an opportunity to give further time to their consideration. When Diesing published his ' Systema ' only two helminths were referred to the Indian elephant, namely, Ascaris lonchoptera and an undescribed fluke supposed to be a distome. The whole subject requires revision, but I think the following species must, for the present at least, be allowed recognition : Fas- ciola Jacksoni (mihi), Amphistoma Hawkesii (mihi), Ascaris lon- choptera (Diesing), Sclerostoma spinuliferum (Baird), and Dochmius Sangeri (mihi). Either the Ascaris or the Sclerostoma is probably identical with Rudolphi's Strongylus elephantis. At the Norwich Meeting of the British Association, in 1868, 394 PARASITES OF ANIMALS I exhibited two flukes received from J. S. Thacker, V.S., of the Madras Army. They were handed to me by the late Dr Baird, and were labelled " Distoma taken from liver of elephant and forwarded for classification/' I stated at the time that these entozoa were identical with certain flukes previously obtained from the duodenum and biliary ducts of an Indian elephant, and which, though carefully preserved in the Boston Museum, U.S., had never been properly described. They were only briefly noticed by Dr Jackson in his ' Descriptive Catalogue ' of the Museum. In the summer of 1868 fifteen specimens of fluke, removed from Burmese elephants, had been forwarded to and received by Professor Huxley from Rangoon, accompanied by a statement to the effect that they were the cause of an extensive and fatal disease in Burmah. Through the kindness of Prof. Huxley I was allowed to make use of his specimens for the purpose of comparison and identification, and thus it became evident that our specimens were of the same species. It was also evident that the species could be none other than that represented by the Boston specimens. Further examination having made it clear that the organisation of these flukes departed from the ordinary distome type, I named the parasite Fasciola Jacksoni, at the same time offering the following description (' Entozoa/ Supp., 1869, p. 80) : Body armed throughout with minute spines, orbicular, usually folded at either end towards the ventral aspect, thus presenting a concavo-convex form ; oral sucker terminal, with reproductive papillae about midway between it and the ventral acetabulum ; intromittent organ J" in length ; digestive apparatus with two main zigzag-shaped canals, giving off alternating branches at the angles thus formed, the ultimate ceecal ramifications occupying the whole extent of the body ; length, when unrolled, from J" to f", breadth J" to f'-" Now, if reference be made to the appendix of the late C. M. Diesing's ' Systema Helminthum/ it will be found that Jackson's statement had not escaped that helminthologist's notice, though, not having seen any specimens, he was not unnaturally led to place the species amongst the distomes proper. In Diesing's subsequently published ' Revision der Myzelminthen,' the species is formally characterised as the Distomum elephantis of Jackson (' Sitzungsberichte d.Math.-nat. Cl.d.k. Akad. d. Wissenchaften,' Bd. xxxii, 1858). In my " Synopsis of the Distomidae," which appeared in the ' Journal of the Linnean Society' for 1861, I had also placed it amongst the distomes, not considering it PACHYDERMATA 395 to be a doubtful form (' Proceed. Linn. Soc./ " Zoology," vol. v, p. 9). These references exhausted the literature of the subject up to the time of the issue of my ' Manual' in 1873, where this fluke is again briefly noticed (p. 13). Several of Prof. Huxley's specimens have been added to the entozoological department of the Hunterian Museum. It is clear that all these notices and descriptions point to the same parasite. The worm has since been more carefully described by Dr E. H. Fitz, from a series of dissections and preparations made by Dr H. P. Quincy, and deposited in the Warren Museum, Boston, U.S. About the middle of June, 1875, I received a letter from General Hawkes, of the Madras Staff Corps, dated Secunderabad, May 12th, 1875, and in reference to the subject before us he writes as follows : " My attention has been recently directed to a very unusual mortality of elephants at this station. Out of twenty-eight elephants under my charge, no less than twelve have died within the last sixteen months, whereas the average annual mortality has been hitherto only two per annum out of thirty-eight in our establishment. In every case of death there appeared to exist serious organic disease quite sufficient to account for such death, but as the mortality increased I had a post-mortem examination made in each case; and although here also organic disease sufficient to account for death was present in each case, yet in every one of these elephants we found the liver-fluke in greater or less abundance." General Hawkes adds : " Meanwhile I have sent you a small box con- taining three bottles, one containing the liver-fluke (Fasciola Jacksoni) referred to in your work on the parasites of domesti- cated animals. It seems possible that the other two species of parasites may not have been brought to your notice. Both of these, namely, the " masuri " and the " soorti," are very common in elephants. They are both found in the intestines only. The "masuri," when present in any quantity, cause considerable disturbance, and the animal instinctively resorts to the eating of earthy which it consumes in large quantities until the bowels are acted on and the worm expelled. The soorti is more common than masuri, and does not seem to inconvenience the animal very much. When expelled from the animal the soorti is a round white worm, like most of the threadworms ; the masuri, on the other hand, is of a delicate flesh color," Shortly after the receipt of this letter I obtained the entozoa in a good state of preservation. Accordingly I wrote to General 396 PARASITES OF ANIMALS Hawkes, stating that the flukes were clearly referable to Fasciola Jacksoni ; that the parasites to which the natives of Hindostan apply the term " soorti " were evidently examples of Ascaris lonchoptera (Diesing), previously called strongyles by Kudolphi ; and that the worms which he called " masuri " were trematodes new to science. I named the species Amphistoma Hawkesii, in honor of the donor. The bottle contained as many as forty-nine specimens. I may here remark that I have made inquiries of the keepers of the elephants at the Zoological Gardens as to whether they have ever seen entozoa that were passed by the animals under their care. They replied in the negative, the keeper of the African elephants (Scott) having made frequent inspection of the fseces. I was the more anxious to secure information on this point since, during my frequent visits to the menagerie, I had observed that the African elephants were in the habit of swallowing large quantities of mud and dirt from small hollows in the ground near the great water-tanks in which they bathe. Prof. Garrod (who had dissected three elephants) also assures me that there has been no trace of an entozoon in any of the Indian elephants examined by him. In one dissected at Edinburgh the same negative result was obtained. From the facts at present in my possession, I conclude that the habit of earth-eating, displayed alike by Indian and African elephants (and, as stated in my account of the equine parasites, shared by horses), is not necessarily due to the presence of parasites. I apprehend rather, that it is resorted to by these animals under any circumstances of intestinal irritation, whether created by entozoa or other foreign agents. The notion of the elephant's intelligent self -cure by eating earth is a very old fable. Captain Forsyth, as quoted by Mr Fleming, alludes to it in his ' High- lands of Central India/ and I find the same ideas recorded by Williamson and Howitt. Forsyth says : " Elephants are very liable to intestinal worms. They generally cure themselves by swallowing from ten to twenty pounds of earth." Captain Williamson says : " They are much troubled with worms, for the cure of which the elephant eats earth. If the dung be inspected there will be seen an amazing number of moving objects, which much resemble pieces of chewed sugar-cane." Some excellent practical remarks are added, testifying to the value of the native remedy called Kallah-nimok, or bit-noben, which is a saline purgative. In Lieut. Ouchterlony's essay (quoted below) no allusion is made to the subject of worms. PACHYDEKHATA 397 General Hawkes afterwards supplied me with further infor- mation. In a letter from Secunderabad, dated July 30th, 1875, he says : " As regards the liver-fluke (F. Jacksoni), it appears from your treatise to have been first observed in 1847. The only other published notice that I have been able to find of it is contained in a letter to a newspaper, dated ' Rangoon, 16th July, 1867/ and is signed 'R. B.' In this letter the unusual mortality of seven elephants in about fifteen days is attributed to the presence of this liver-fluke, the two other parasites (Amphistoma and Ascaris lonchoptera) being also present in the intestines." " Now (continues General Hawkes), in every case at which I was present flukes were found in greater or less numbers in the gall-ducts of the liver, and the Amphistoma was also as constantly present in the intestines, the soorti (Ascaris lonchoptera), contrary to the general experience of the elephant attendants, being less frequently met with, though from its color and slender shape it is not so easily detected among the huge mass of faeces as the larger Amphistoma." Speaking of the amphistoma General Hawkes says: "This internal parasite is well known to all who possess elephants. It is alluded to by Dr Gilchrist in his treatise on the ' Diseases of Elephants/ first published in 1841, but he merely mentioned it under its local name, masuri, and made no attempt either to describe it scien- tifically or to ascertain its place in the natural system. As far as my experience goes it is only found in the intestines. These parasites appear to be very generally present in the elephant. When their numbers are few the ''host'' is probably not much inconvenienced, but when present in any great quantity they undoubtedly cause much irritation. When this is felt, the animal, as before remarked, instinctively resorts to a simple and effectual remedy. He eats a quantity of earth, which purges him thoroughly and expels the amphistoma. The mahawats are of opinion that whilst the elephant is eating earth to relieve himself of the pests the daily allowance of rice should be scrupulously withheld ; and they say that if the rice, which is given uncooked, is eaten by the animal under these circum- stances, excessive purgation is induced, which frequently results in death. How far this opinion is founded on fact I am unable to say, but the mahawat's name for this disease means ' fast- ing/ and bears testimony to the generally received notion of the necessity of withholding the rice when the animal is eating earth." 398 PARASITES OF ANIMALS When describing the parasites of the horse (p. 358), I spoke of Collins' amphistome from that animal, but in the letter addressed to me from Simla, 22nd March, 1875, Mr. Collins made no allusion to the earth-eating habit. He wrote : " I forward you by this mail parasites found in the colon of a horse that died, a subject of fever peculiar to this country. There were about a thousand of the parasites, and nearly the whole of them were situated close to the caecum, and were loose in the gut. Not having seen parasites at all similar to these, I have forwarded them for identification. They were of a brick-red color when first obtained." These explicit statements by Mr Collins are interesting from many points of view. One has only to place his specimens side by side with those from the elephant in order to satisfy one's self that the two forms are distinct. For the reasons already stated I provisionally called the worm Amphistoma Gollinsii. It is probable that other veterinary surgeons have encountered this entozoon in India ; but, unless they can point to some published account of the fact, Mr Col- lins is entitled to be considered as its discoverer. Doubtless many other European residents in India, Ceylon, and Burmah, must, like Dr Gilchrist, be well acquainted with the masuri as such, though unaware of their zoological position. In a record of the post-mortem examination of one of the victims of the Secunderabad epizooty, the veterinary surgeon said : " No doubt disease of the lungs and subacute inflamma- tion of the bowels were the immediate cause of death, but the large number of flukes in the liver and the intestinal parasites (i. e. the amphistomes) account in a great measure for some of the symptoms shown, and these symptoms accord in many respects with those shown in elephants that died in Burmah during the epizooty (rot) in 1867, as recorded by R. B., no- tably, refusal of food, standing with mouth open, restlessness, and puffiness about the head and shoulders. The liver para- site is no doubt the same referred to by R. B., and is that termed by Dr Cobbold Fasciola Jacksoni." In reference to a later case the same officer remarks : " I carried out the post- mortem examination with special reference to inquiry as to the probability of the mortality amongst elephants at this station being of parasitic origin. This was suggested to me by the former case. The post-mortem appearances differed in every respect. There were flukes in the liver, but in no great quantity, and the structure of the liver was sound. Although PACHYDERM AT A. 399 not assisted by this case in attributing the mortality to para- sitic origin, I am strengthened in my opinion that the death of the previous elephant was due to disease caused by the presence of the liver fluke." This report, by Mr W. S. Adams, is to some extent in harmony with later information. An epi- zootic outbreak amongst elephants has occurred in England, at Sanger's Circus, and I had opportunity to examine one of the dead animals. In my own opinion, and in that of Mr F. Smith, the veterinary surgeon who attended the animals professionally, the disease was due to parasites. I obtained large quantities of Amphistoma Hawkesii from the intestinal canal, and also other worms. The death of one of the elephants was made the subject of litigation, when, as might be expected, great diver- sity, of opinion as to the cause of the fatal issue prevailed. Mr Smith, an old pupil of mine, regarding the amphistomes and strongyles as the cause of death, wrote to the effect that " some of the worms were found between the coats of the intestine, and others on the free surface of the gut, whilst the excretory ducts of some of the glands were found blocked with them." The animal examined by myself on the 24th of August, 1876, yielded numerous examples of Amphistoma Hawkesii, Ascaris lonchoptera, and Dochmius Sangeri, the last species being so named by me after the owner of the circus who lost the herd of elephants by the epizooty. The male Dochmii measured f and the females f of an inch in length. Here I must reluctantly quit the helminths of -elephants, adding only an expression of surprise that Dr Max Schmidt should have had so little to say concerning them in his otherwise instructive memoir on 'The Diseases of Pachyderms ' (quoted below). I have but a few words to offer respecting the ectozoa. A species of mite has been described whose generic position appears doubtful. I allude to Homopus elephantis of Fiirsten- berg, or Symbiotes elephantis of Grerlach. According to Megnin it is a nymphe adventive or hypope of a variety of Tyroglyphus siro. This acarus is abundant in old forage. Another ectozoon is Ham atomy zus elephantis. It differs from the lice proper in many respects, but, according to Piaget, the reproductive organs resemble those of Haematopinus. In ' Science Gossip' for June, 1871, Mr H. C. Eichter describes "a new form of parasite," which is called Idolocoris elephantis. The insect, which was one line in length, was found upon an elephant in Ceylon. According to Walker it not only constituted the type of a new 400 PARASITES OF ANIMALS genus, but of an altogether new family of the Hemiptera Hete- roptera, coming very near to the bed-bugs ( Acant hid&) . It is a huge sucking louse. From the discussion which followed, it seems that the parasite had several times been seen before, and was none other than E. Piaget's Htematomyzus elephantis. Excellent figures accompany Richter's and Piaget's descrip- tions. Notwithstanding Piaget's explanation, I think the specific name, longirostris, would have been a more appropriate appellation. BIBLIOGRAPHY (No. 51). (Anonymous), "Diseased Elephants/' see f Lancet/ Sept. 2, 1876 ; also "Report of the Case at Law (Jamrach v. Sanger)," given in the 'Veterinarian/ Dec., 1877, p. 886. Cobbold, T. 8., " Description of a species of Trematode from the Indian Elephant, with remarks on its Affinities," ' Quart. Micros. Journ./ Jan., 1869 ; see also ' Entozoa/ supp., 1869, p. 80. Idem, " On the Destruction of Elephants by Parasites, with remarks on two new species of Entozoa and on the so-called Earth-eating habits of Elephants and Horses in India," ' Veterinarian/ Oct., 1875. Idem, "Further Remarks on Parasites from the Horse and Elephant, with a notice of new Amphistomes from the Ox," ibid., Nov., 1875. Diesing (1. c., in text). Fitz, R. H., "Anatomy of Fasciola Jacksoni," 'Rep. of Boston Soc. Med. Sci./ in the 'New York Med. Journ./ Nov., 1876. Fleming, Q., "The Diseases of Elephants " (chiefly from Captain Forsyth's work on the t Highlands of Central India 0, 'Veterinarian/ March, 1873, p. 181. Megnin, "Mem. sur les Hypopes," in Robin's 'Journ. de 1'Anat. et de la Physiol./ 1874 (H. elephantis), p. 248.Ouchterlony, J. W., " An Essay on the Management of the Elephant, and its Treat- ment in ordinary Diseases," ' Rep. of Vet. Med. Assoc./ Nov., 1872, and pub. in 'Veterinarian/ Jan., 1873, p. 65. Piaget, E., " Description d'un parasite de 1'elephant," ' Tijschrift voor Entomologie/ 1869, p. 249.Richter, H. C., " A new form of Parasite (Idolocoris elephantis)," ' Science Gossip/ 1871, pp. 131, 185, 211, 278. Schmidt, Max, "Die Krankheiten der Dick- hauter," ' Deutsche Zeitschrift f. Thiermed. und vergleichende Pathologie/ f. Nov., 1878, s. 360. Williamson, T., ' Oriental Field Sports/ London, 1807, vol. i, p. 138. The parasites of the Rhinoceridte have been even less studied than those of elephants. In 1856 Prof. Peters described a tapeworm from Bruce's rhinoceros (R. Africanus), which he named Taenia gigantea. In 1870 Dr Murie, under the provi- PAOHYDERMATA 401 sional name of T. magna, published a description of the strobile of the same cestode from an Indian rhinoceros (R. unicomis). From a total misconception of the character of the proglottides, Murie was led to suppose that the segments of the strobile were very deep as well as broad ; whereas the proglottids are remarkably narrow, thus partaking of the characters of the Tsenias of the larger herbivora in general. In a subsequent paper Peters pointed out these errors. Murie had, in fact, rolled several segments into one. In 1877 Professor Garrod encountered the same cestode in Rhinoceros sondaicus, and, following Peters' example, separated it from the Tsenise proper (Plagiot&nia gigantea). The idea of generically separating tapeworms possessing a more or less striking breadth of strobile is not one which commends itself to my view, seeing that many of the tapeworms of herbivora closely resemble the rhinoscerine cestodes in this respect. As Diesing hints, this tapeworm comes near to T. perfoliata, but Garrod's and Peters' figures both show that Plagiotcenia wants the neck-lobes. The pre- sence of cephalic appendages may be regarded as generically distinctive, but it does not appear that Blanchard separated the perfoliate tapeworm of the horse from the Tgeniae proper on this ground. Therefore, in my account of the equine tapeworms, I have not adopted his genus Anoplocephala. I may remark, in passing, that if the distinctions, as between armed and un- armed, or between proboscis-bearing (Rhynchot&niada) and non-proboscis-bearing tapeworms (Arynchotceniada) , are to be maintained, they should be expressive of divisional or sub- ordinate value. Dr Weinland's arrangement, having reference to the thick- and thin-shelled ova (Sclero- and Malaco-leptidota), is, perhaps, preferable. The whole subject of classification requires revision, but it should be undertaken by some helmin- thologists practically acquainted with a large number of cestode types. As Garrod has well observed, Plagiotaenia enjoys a wide geographical distribution, infesting alike Indian and African hosts. Prof. Garrod, I observe, speaks of the head of the mature tapeworm as the scolex an extension of the mean- ing of a term not usually recognised. In this, however, he only follows Peters' unfortunate example. The wide distribution enjoyed by Peters' Plagiotsenia is probably equalled by that -of the rhinocerine stomach-bot (Gastrophilus rhinocerontis, Owen). This parasite was origin- ally described in 1840, and since that time it has been fre- 26 402 PARASITES OP ANIMALS quently encountered both in India and Africa. To Mr Spooner Hart, of Calcutta, I am indebted for a large number of speci- mens; their size exceeding that of any other bots that have come under my notice. Probably this parasite infests the stomach of rhinoceroses generally ; at all events, it occurs in R. unicornis, R. bicornis, and R. simus. At present the imago is unknown. The longest Iarva9 in my possession measure 1J", but Brauer records specimens up to 35 mm. in length by 10 mm. in thickness. In African hosts M. Delegorgue found these parasites in prodigious numbers. BIBLIOGRAPHY (No. 52). Brauer , ""Bot of the Rhinoceros," 'Monogr. der CEstr./ 1863, s. 92. Cobbold, "Note on Para- sites presented by Messrs Danford, Hart, and others/' ' Vete- rinarian/ 1875, p. 513. Goquerel and Salle, in f Ann. Soc. Entom. de France/ 1862 (quoted by Brauer). Delegorgite, 'Voyage dans 1'Afrique ' (quoted by Brauer). Garrod, "On the Taenia of the Rhinoceros of the Sunderbunds (Flag, gig., Peters)/' < Proc. Zool. Soc./ Nov. 20, 1877, p. 788. Hope, in ' Trans. Entom. Soc./ 1840, p. 259. Joly, M. N., " Recherches Zool. (&c.) sur les (Estrides.(&c.)/' in 'Ann. des Sciences (&c.) de Lyon/ 1846 (quoted by Brauer). Murie, J., " On a probably new species of Taenia (T. magna ?) from the Rhinoceros/' 'Proc. Zool. Soc./ 1870, p. 608. Peters, W. y "Note on the Tsenia from the Rhinoceros, lately described by Dr J. Murie/' ' Proc. Zool. Soc./ 1871, p. 146. Very little has been written respecting the parasites of the Hippopotamida and Tapiridte. I think it was Livingstone who first drew attention to the fact that the river-horse or sea-cow is much infested by tapeworms, but I have not seen any published description of the worm. Dr. Murie, during his sojourn in Egypt, found a solitary bot embedded in the soft parts surrounding the eye, and judging from his figure the species is new to science. Provisionally I speak of it as the Hypoderma Muriel. In the paper (quoted below) Murie appends a list of all the animals in which bots have been found. Though chiefly taken from Brauer, it is useful and tolerably complete. So far as I am aware no cestodes have been described as infesting tapirs ; nevertheless, at least five other kinds of helminth have been found in Tapirus Americanus. Of these, two are flukes (Amphistoma asperum and A. pyriforme), and three are nema- todes (Sclerostoma monostechum, Spiroptera mediospiralis, and Sp. chrisoptera). The three species first named occupy the caecum, PAOHYDERMATA 403 whilst tlie others are found in the stomach. According to Molin's description, both species occupy tuberous excrescences of the mucous membrane, thus reminding us of the similar habit enjoyed by Sp. megastoma in the horse. The 8p. chry- soptera is a comparatively large species, the males measuring an inch, and the females as much as an inch and a half in length. Both of the spiropteras were obtained from tapirs by the indefatigable Natterer, Sp. mediospiralis being also pro- cured by him from the aguti. If I have read Molin correctly, as many as thirty-four examples of 8. mediospiralis were taken from a single excrescence in the stomach of the tapir. Up- wards of a hundred specimens were procured, collectively, from three similar stomach-excrescences in Dasyprocta aguti. These, and the other tapirine parasites above mentioned, were originally discovered in Brazil. BIBLIOGEAPHY (No. 53). Dwsing, "Neue Gattungen Binnen- wiirmern nebst enem Nachtrage zur Monographie der Amphis- tomen," in ' Annalen d. Wien. Museums,' Feb., 1839, s. 236. Idem, ' Systema/ Bd. ii, s. 306. Mplin, " Una monografia del genere Spiroptera," in ' Sitzungsb. der math.-naturw. Cl. d. k. Akad. d. Wissensch./ Bd. xxxviii, s. 1001, 1859. Murie, "On a larval CEstrus found in the Hippopotamus/' ' Proc. Zool. Soc./ 1870, p. 78. The osculant position of the anisodactyle pachyderms (Hy- racidce), formerly classed as rodents, renders it desirable that their parasites should be briefly noticed in this place. Pro- bably these animals, zoologically speaking, come nearest to the rhinoceroses, but Prof. Owen showed that, anatomically, they possessed marked affinities with the sloths. The klipdas or dasse (Hyrax capensis) is infested by a tapeworm, of which hitherto the proglottides only appear to have been seen (Ttenia hyracis, Pallas). Under the name of Coenurus serialis a larval cestode has been described by Gervais, the same parasite being called Arynchotenia critica by Pagenstecher (" Zur Naturges- chichte der Cestoden," in 'Sieb. u. K611. Zeitschrift '). A variety of nematodes have also been observed in the Cape hyrax. Of these, the so-called Physaloptera spirula is classed as doubtful by Molin and Diesing. Hemprich and Ehrenberg furnished brief descriptions of four other nematodes. Two of these worms were placed in the genus Oxyuris (0. pugio and 0. flavellum), and the other two in the new genus Crossophorus, which they formed for their reception (G. collaris and C. 404 PARASITES OF ANIMALS tentaculatus). The whole of these nematoids were obtained either from the caecum or large intestine. An able article in the ' Natural History Review ' for July, 1865, attributed to Professor Huxley, expressed very clearly the popular notion as to the great danger of the flesh of swine considered as a source of human parasites. No doubt the filthy pachyderms in question (Suidce) are much infested by helminths, some of which gain access to man, but swine are neither attacked by a greater variety of entozoa than other domesticated animals, nor are they so frequently a source of human tapeworms as cattle. In the article above quoted the following passage occurs : " Of all animals, feral or domestic, the common pig is beyond all doubt the most fertile source of human entozoa ; at least, of important parasites, Trichina spi- ralis and the tapeworm would, there is good reason to believe, cease to infest us, did not this favorite quadruped act the part of a communicating medium. " This paragraph was evidently written under the impression that "the tapeworm" most commonly found in man was derived from the hog. So far back as 1864 I showed that this was an entire mistake. Flukes are rare in swine; nevertheless, Fasciola Jiepatica and Distoma lanceolatum are occasionally present in the domestic hog, and the peccaries (Dicotyles) are infested by an Amphistome (A. giganteum). This large species, f" in length, formed the basis of an admirable account of the anatomy of this genus of worms which the learned Vienna helrninthologist, Diesing, wrote before he was deprived of his eyesight. The merits of that respected systematist's investigations have, I think, been much underrated, in consequence, no doubt, of the artificial character of his system of classification. For all that, his writings remain invaluable. Turning to the cestodes of swine, there is not, so far as I am aware, any evidence of the occurrence of sexually-mature tapeworms either in the hog or its allies ; but the frequency of larval cestodes, known as measles (Cysticercus tela cellulose] , was well known to the early Jewish writers. In the first part of this work I devoted as much space as I could spare to the consideration of Cysticerci in general, and the pork-measle in particular ; but an exhaus- tive knowledge of the subject in relation to hygiene can only be acquired by consulting the principal original memoirs (quoted in the Bibliographies Nos. 13 and 14). In a Westphalian ham, part of which was sent to me for examination, I calculated that PACHYDEEMATA 405 each pound of the flesh must have contained upwards of 600 Cysticerci. I was informed by the donor, Dr Prior, that in spite of the disgusting state of the meat much of it had been eaten by the well-to-do family who purchased the ham. Cysti- cerci occasionally occupy the brain of the pig in considerable numbers. Florman recorded a case of this kind where their presence gave rise to vertigo in all respects resembling the gid ordinarily produced by Coenurus in the sheep. As regards the larger cestode larvge, Gysticercus tenuicollis and Echinococcus veterinorum are of frequent occurrence. One not unfrequently encounters the former in the mesentery, whilst the liver of the hog is sometimes so crowded with hydatids that scarcely any of the glandular substance of the organ remains visible. It is surprising how little the infested bearers appear to be incon- venienced in such cases. In the winter of 1859, and in the autumn of 1860, I found large cystic entozoa in an African Wart- hog and in a Red River hog. These animals had died at the London Zoological Society' s Menagerie; and as the worms appeared to me at the time to be quite distinct from the ordi- nary slender-necked hydatid, they were named, respectively, Cysticercus phacoch&ri oethiopici and G. potamoch&ri penicillati. The solitary example from the wart-hog was found in a cyst near the colon ; whilst of the five large bladder-worms obtained from the Red River hog, one in- "i fested the liver and the other FlG . 66 ._ He ad and neck of oy,ticm, from the four were lodged in the folds ^ d al Kiver hog " Ma s nified 60 diameters - Ori - of the mesentery. The caudal vesicle of the worm from the wart-hog measured 3|" in diameter, the vesicle of the other bladder-worm being much longer. A reference to the original figures will show that these forms are distinct. Swine are largely infested by nema- todes. The best-known form is Ascaris lumbricoides, which Dujardin regarded as distinct (A. suilla). The hitherto dis- puted identity of this worm with the human lumbricoid being no longer questionable, the importance of the entozoon in rela- 406 PARASITES OP ANIMALS tion to lumbricoid endemics must at once be obvious ; I have already, however, dwelt upon this subject when treating of the human parasites. In like manner, the subject of the flesh- worm disease, which is due to Trichina spiralis, cannot be discussed in this place, as I have fully entered upon it in connection with trichinosis in the human subject. What may be the nature of the small threadworms found by Leidy in the extensor muscles of the hog I cannot say, but Diesing inferred that they might represent a distinct species (Trichina affinis). As regards the allied genus Trichocephalus, the common species infesting swine (T. crenatus), appears to be rarely absent. It not only infests the common domestic and wild hog, but the peccaries and wart-hogs. These entozoa are probably harmless to their bearers. In reference to them Krabbe says : " When the eggs are expelled with the excrement and pass into water, then the embryos, after several months' furlough, and there undergoing further development, are transferred to the swine's intestinal canal." If I rightly understand the paragraph (' Husdyrenes Indvoldsorme,' p. 28), Krabbe states that the embryos are still within their egg-coverings when infection takes place. The maw-worm of the hog is known as Spiropiera strongylina. It was described and figured by Gurlt. The males measure J" and the females |" in length. Specimens of this worm were supposed to have been found by Natterer in Dicotyles albirostris ; but it seems that the worms in question represent a distinct species, if not an altogether new genus. In the year 1864 Professor Simonds placed in my hands a very singular nematode, to which I gave the binomial term Simondsia paradoxa. Numerous examples of this worm were found by Prof. Simonds occupying cysts within the walls of the stomach of a hog which had died at the London Zoological Society's Menagerie. In my introductory treatise I wrote of it as follows : " The worm in question has been regarded by Mr Simonds as a species of Strongylus, but I am inclined to think that its affinities will place it nearer to the genus Spiro- ptera. At present I have only examined the female, which is characterised by the possession of a multitude of large tentacle- like * appendages surrounding the neck. These processes, by their aspect, remind one of the so-called branchial projections on the back of Eolis, but in this worm I believe them to bo special folds formed for the lodgment of unusually developed uterine organs. The female worm is about }" in length/' PACHYDERM AT A 407 In the interval that has elapsed I have been unable to supply further particulars, and unfortunately the original drawings of the worm have been lost. The habits of the parasite remind us of Spiroptera megastoma infesting the walls of the stomach of the horse. Not improbably this singular entozoon may turn out to be identical with Molin' s Spiroptera sexalata, and if so, it may correspond with Spiroptera strongylina. However, Diesing afterwards recognising, as I had done, the desirability of separating this last-named worm from the SpiropteraB proper, formed for it his new genus Physocephalus. He then called the worm Physocephalus sexalatus. If, as is probable, my Simondsia and Diesing's Physocephalus are identical, the species found by Simonds ought to be recognised by the generic title which Diesing proposed. His genus was established about four years before I described my Simondsia. Diesing was evidently lert up to the recognition of the generic distinction of the worm by Molin' s examination and description of the worm. As, in my original account of the worm found by Simonds, I spoke of numerous appendages to the neck, it is evident that further investigation is necessary to clear up the question of identity. According to Molin and Diesing the male Spiroptera sexalata measures rather beyond J" and the female beyond 4" i n length. Neither Diesing nor Molin speak of Natterer's worms as being found encysted. In fact they were free. Molin simply re- marks : " lo ne esaminai in oltre 6 esemplari maschi e 77 femine raccolti in parte dal muco che revestiva le pareti dello stomaco, ed in parte dal pasto contenuto nello stesso organo di un Dicotyles albirostris femina ai 24 Aprile, 1826." After all that has been said it may be that my Simondsia paradoxa and Diesing' s Physocephalus sexalata are quite distinct, and that like the large- and small-mouthed maw- worms of the horse (Spiroptera megastoma and S. microstoma) they play a corre- sponding role. Before very long I hope to set this question definitively at rest. Passing to the strongyloid nematodes one of the most remark- able and important species is Stephanurus dentatus. In the 1 Annalen des Wiener Museums ' for 1839 (s. 232) this worm was first described by Diesing, who employed the generic title as expressive of the crown-like figure of the tail of the male worm. Diesing wrote as follows : " At Barra do Rio Negro, on the 24th of March, 1834, Natterer discovered this peculiar genus of worms occurring singly or several together in capsules situated 408 PARASITES OF ANIMALS amongst the layers of fat in a Chinese race of Sus scrofa domestica. The males measure from ten to thirteen lines long, the females from fifteen to eighteen lines, the former being scarcely a line in breadth at the middle of the body, whilst the latter are almost a line and a half in thickness. The curved body thickens towards the tail, is transversely annulated, and viewed with a penetrating lens is seen to be furnished with integumentary pores. The oral aperture opens widely. It is almost circular, and is supplied with six teeth at the margin. Two of these standing opposed to one another are larger and stronger than the rest. The tail of the male, when spread out evenly, is surrounded by a coronet of five lancet-shaped flaps ; the combined flaps being connected together from base to apex by means of a delicate transparent membrane. The single spiculum situated at the extreme end of the tail projects slightly forward and is surrounded by three skittle- shaped bodies. The tail of the female is curved upon itself, rounded off, and drawn out at the extreme end into a straight beak-shaped point; whilst to both sides of the stumpy caudal extremity of the body short vesicular prominences are attached. The female reproductive outlet occurs at the commencement of the second half of the body. Thus, judging by its external characters this genus is most closely allied to Strongylus." In reproducing Diesing's description I have here rendered the translation somewhat more freely than in my previous record of the dis- covery given in 'Nature' (1871). The original description is supplemented by a brief account of the internal anatomy of the worm. So far as I am aware no subsequent notice of this entozoon appeared until the year 1858, when Dr J. C. White gave some account of a " find " made in the United States. This re-dis- covery was reported in the sixth volume of the ' Proceedings of the Boston Natural History Society/ Dr White says : " The worms were found in the leaf-yard of an apparently healthy hog, in the adipose tissue near the kidney. They occupied a space of the same about the size of a man's fist and had burrowed through the mass in every direction, forming canals three or four milli- metres in diameter, which terminated in cysts. On cutting open these cavities, which did not communicate with each other, they were found filled with pus, and in each were two worms, male and female." Dr White expresses his opinion that the worms gained access to the tissues " by boring through the circulatory PACHYDERMATA 409 system while in the embryonic condition." I think that Dr White deserves great credit for his correct diagnosis of the species, and all the more so because he was evidently not acquainted with Diesing's original memoir. He expressly speaks of the " scanty descriptions " hitherto given of the worm. As Dr White had accurately determined the species in the presence of an American Scientific Society, it is remarkable that neither Verrill nor Fletcher should have identified the worm. On the 10th of January, 1871, I received a letter from Prof. W. B. Fletcher, of Indianapolis, Indiana, U.S.A., and in it he announced that he had " found a worm " infesting the hog. The parasite was so abundant in swine that he obtained it in " nine out of ten hogs " which he had examined. Dr Fletcher sent me specimens of the worm for description and identification, when I at once recognised them as examples of Diesing' s Stephanurus dentatus. As Dr Fletcher's first commu- nication to myself was undated I do not know precisely when he first encountered the worm, but it was in 1870. In that same year Prof. Verrill received specimens of the worm. He says that they were received from Dr J. C. White. Failing to identify the parasites as Stephanuri, Verrill (making no allusion to the ' Proceedings of the Boston Society ; ) not unnaturally supposed he had to deal with an entozoon that was new to science. Accordingly he immediately described and figured the worm under the combined title of Sclerostoma pinguicola. If these data are correctly given, the re- disco very of the worm in America was due to Dr J. C. White j its identity with Stephanurus being subsequently acknowledged by Diesing, and afterwards, quite independently, by myself. I gather this partly from Diesing' s ' Kleine helminthologische Mittheilungen ' (s. 281), published as a supplement to his ' Revision der Nematoden ' (186061). Until quite recently Diesing's recognition of the identity of White's parasites with Stephanuri was unknown in America. My conclusions arose from an examination of the actual specimens, whereas Diesing was entirely guided by White's description. In this connection, moreover, a still more interesting re-discovery remained to be recorded. The original announcement which I made in the f British Medical Journal ' for January 14th, 1871, was followed by another in the same periodical for September, 1871. As stated in my second letter and repeated in my notice of Krabbe's 410 PARASITES OF ANIMALS memoir on " Parasites " (' London Medical Record/ April 2, 1873), the President of the London Microscopical Society (through Mr Slack, who was at that time the secretary) forwarded to me a box of microscopic slides received by the Society from Australia. The slides displayed parasites of various kinds. Having been requested to identify the parasites I had the good fortune to recognise amongst them characteristic examples of Stephanurus dentatus. Thus was first made known the fact that this singular genus was not confined in its geographical distribution to the two American continents, but that it extended to Australia. The order of the principal " finds " and descriptions may therefore be thus restated. Natterer discovered the worm in Brazil in 1834. Diesing described it in 1839. Dr J. C. White re-discovered and identified the worm in 1858. It was subsequently found by Dr N. Cressy and by Dr Fletcher. These three observers all encountered the parasite in the United States (1858-70). Prof. Verrill re- described the worm as new to science in Sep- tember, 1870. Diesing confirmed White's diagnosis in 1860. I identified the worm from Fletcher's " find " in 1871. Dr Morris supposed he had discovered a new entozoon in Australia in July, 1871. The Australian worms were identified by me as examples of Stephanurus dentatus in October, 1871. The importance of Stephanurus in relation to porcine epizooty and the supply of animal food cannot be ignored. As remarked in my communication to ' Nature/ it must be quite obvious that so large a parasite, when present in the hog in any considerable numbers, would give rise to serious disease, even if it were not productive of fatal results to the bearer. In one of his nume- rous communications to myself, Prof. W. B. Fletcher writes as follows : " It is my opinion that this parasite is the cause, in some way, of the hog cholera, which has created such sad havoc within the past ten years over the pork-producing parts of America. One farmer told me, a few days ago, that within a month his loss alone from this cause was over one hundred head; and sometimes, in one neighbourhood, in a few days' time, thousands have perished, although this season is not a cholera year, as our farmers say. I advised one farmer to burn or bury the dead animals, but he informed me that he believed that fewer hogs die of the disease after eating the dead animals than those kept from them. Unfortunately, in this State there is no law guarding the spread of disease, PACHYDERM ATA 411 neither is there any reward of reputation or gain for pursuing any investigation that would bring pork and beef packers into disrepute. I myself could not get a pig's kidney or beefs liver in our city market, because I made investigations in some Texas cattle (being cut up in our market), which damaged their sale a few years ago." In a third letter Dr Fletcher tells me that greater facilities for examining the carcases of hogs had since been accorded him through the liberality of a Liverpool firm of pork-packers, who had already killed 75,000 hogs during the summer season, i.e. up to the date of the first week in July. In hot weather the slaughtering is conducted in ice-houses. Prof. Fletcher's views receive confirmation from the statements made by Dr Morris, who speaks of the pigs as dying from some mysterious disease, and thinks that the worms may be the cause of the porcine mortality. Writing to the President of the London Microscopical Society from Sydney (July 12th, 1871), Dr Morris says: "It is just possible that some pigs may survive the irritation such a swarm of young worms must set up ; others, again, may die from peritonitis, hence the sudden deaths amongst the pigs." I think Dr Morris' view is perfectly correct, but whether it be so or not, it is (as observed by me in ' Nature ') interesting to notice the remarkable correspondency of the conclusions arrived at by Drs Fletcher and Morris independently. It will probably not be difficult to ascertain hereafter whether or not the maladies respectively termed "hog cholera" and "mysterious disease" are one and the same disorder, but whatever happens in this respect, it is now quite clear that this parasite, hitherto little regarded, and for many years past persistently overlooked, is extraordinarily prevalent in the United States, and, perhaps, equally so in Australia ; it being further evident that its presence in the flesh of swine is capable of producing both disease and death. The statement of the worthy American farmer that the swallowing of infested flesh by pigs does not necessarily involve the pig- eating hog in a bad attack of the so-called " cholera disease " requires to be further tested, and it also remains to be proven whether or not the Stephanurus be capable of passing through all its developmental changes from the egg to the adult form within the body of the bearer without having at some time or other gained access to the outer world. The comparatively large size of the ova, which I find to be about 3 ~ // , or more than four times the size of Trichina-eggs, is not with- 412 PARASITES OP ANIMALS out significance, but as yet we are entirely unacquainted with the larvaD of Stephanurus. If no intermediary bearers are necessary to its development, we ought not to have to wait long for a complete record of the life- history of Stephanurus dentatus. In conclusion, I will only further remark that since thousands of hogs are infested by this entozoon the subject is worth further investigation. I believe that Prof. Fletcher brought the matter under the notice of the United States National Swine Breeder's Association, which met at Indianapolis in November, 1872, but with what success I have been unable to learn. The wealthy agricultural societies of Great Britain pay little or no regard to the subject of parasites, although thousands of valuable animals annually perish from the injurious action of entozoa. Of the remaining nematodes infesting swine I must particu- larly mention Sclerostoma (Strongylus) dentatum and Strong i/lnx paradoxus, the last named being generally regarded as identical with Dujardin's S. elongatus. The first of these two parasites infests the small intestines, the male and female worms alike measuring about '' i n length. The females are sometimes a trifle longer. The Sclerostoma dentatum is an abundant para- site, infesting all varieties of swine and also peccaries ; but it is apparently incapable of serious injury to the bearer. Schneider selected the male S. dentatum for classificatory purposes. In this worm the arrangement of the rays of the hood is simple, forming a good central type. Dr D. V. Dean, in his excellent report of St Louis Board of Health (1874), speaks of Strongylus dentatus as if it were the same entozoon as Stephanurus. The confusion of nomenclature would have been avoided if Diesing had called the renal worm Stephanurus Nattereri. I hope this title will yet be adopted to prevent future mistakes. The lung-worm (S. paradoxus) is by no means harmless, being a frequent cause of fatal husk in young pigs. It is a viviparous worm, the females acquiring a length of 1^", whilst the males rarely exceed f". Under the title Gongylonema pulchwnn, Molin has noticed yet another filari- form nematode infesting the wild hog ; and, lastly, the lamented Eussian traveller, Fedschenko, has published a full description of a new species of Gnathostoma (G. hispidum), which infests the coats of the stomach alike of the wild and domestic hog. One of the most interesting parasites of swine is the large acanthocephalous entozoon (Echinjorhynchus gigas). It infests the small intestines both of the wild and domesticated hog, and PACHYDERM ATA 413 it was also obtained by Natterer from the collared peccary of Tayazou. Common as the great Echinorhynchus is in the United States (and it is scarcely less so on the Continent) I believe that few, if any, of the museums in the United Kingdom of Great Britain contain this large entozoon. It is a curious fact that it does not exist in the Hunterian Collection, where, however, there is displayed a very fine set of acantho- cephalous parasites from whales. When in the year 1865 I mounted, with my own hands, 200 preparations of entozoa for the Museum of the Royal College of Surgeons, I had not so much as seen a specimen of this worm. Much scientific interest attaches to this parasite from the fact that Schneider discovered that the embryos of E. gigas take up their residence in the larvae of the cockchafer (Melolontha vulgaris). He thinks it identical with the Echinorhynchus hominis of Lambl. Leuckart disputes this identity, and compares Lambl's worm with the Echinorhynchus angustatus of our fresh-water fishes. The E. spirula of certain Brazilian monkeys and of the Barbary ape bears a strong resemblance to the species from the hog. On the strength of Lambl's case and it is the only genuine instance of the kind on record Prof. Leuckart devotes no less than 125 pages of his great work to the consideration of the struc- ture and development of the thorn-headed intestinal worms. This worm demands especial attention. Speaking of the hog's Echinorhynchus, Prof. Yerrill, in his ' Connecticut Report/ says that " sometimes the intestine of a hog is found perforated by so many holes that it cannot be used in the manufacture of sausages/ 7 From Mr George Wilkins I learn that the pig- slaughterers of our English metropolis are well acquainted with these perforations, which are sometimes so numerous that the gut looks as if it had been " riddled " with swan-shot. No wonder that diseased hogs, afflicted with these formidable parasites, go about, as Yerrill expresses it, "continually squealing and grunting, especially in the morning." That they are also "cross and morose, and given to biting and snarling at their companions," is by no means astonishing. " In severe cases," remarks Yerrill, " hogs afflicted with this parasite are weak in the loins, and have the membranes in the corners of the eyes swollen, watery, and lighter colored than usual." It is some comfort to know that Lambl's human case is unique, and that so long as people abstain from eating cock- chafer larvae they are not likely to be infested by Echino- 414 PARASITES OF ANIMALS rhynchus gigas. In the first book of this work I have given my reasons for not regarding Welch's " encysted Echino- rhynchus in man " as a genuine example of this curious genus of entozoa. The external parasites of swine are not so numerous as might be expected from the habits of their hosts. The most common ectozoon is the hog louse (Hamatopinus suis). This disgusting little insect is about J" in length. Almost equally common is the hog mite. Though hitherto considered as a distinct species (Sar copies suis, Gurlt), it is regarded by Megnin as a mere variety of Sarcoptes scabiei. As Gerlach and others have remarked, it is readily transmissible to man. The Sarcoptes squammiferus, of Furstenburg, is only another name for this variety of S. scabiei. Speaking of this scab-insect Megnin says : " This parasite was first encountered by Spinola and Gurlt, and afterwards by Muller." He then adds : " A Ceylon wild boar died at the menagerie of the Museum of Paris of a chronic affection of the skin which had transformed its integument into a vast lichen." Lastly, as regards the protozoal parasites I can only remark that the psorosperms (spoken of as Rainey's corpuscles or as Miescher's utricles) are often very abundant in the flesh of otherwise perfectly healthy swine. Having dwelt upon the character of such organisms in the first moiety of this work, I will only remark that the full significance of these singular bodies yet remains to be determined. Rainey's notion that they represented early stages of cysticercal growth is altogether untenable. According to Behrens, as quoted by Davaine, psorosperms are especially abundant in the flesh of swine which have recovered from the disease called mal rouge. On the subject generally, the writings of Rivolta, Waldenburg, Eimer, and Siedamagrotsky are espe- cially trustworthy. Full references to these and other authorities are given in the synopsis of the 2nd edition of Davaine's well- known treatise. BIBLIOGRAPHY (No. 54). (Anonymous), "On Parasitic Maladies, especially Measles, of the Pig/' from ' Scottish Farmer and Horticulturist/ in ' Edin. Vet. Rev./ p. 688, 1861. Ballard, E., " On Diseased Meat, and what to observe in cases of suspected Poisoning by Meat or Sausages (infected with Entozoa, &c.)/' None Very numerous. 440 PARASITES OF ANIMALS I have said that tapeworms prove fatal to young birds, even to nestlings. A notable instance of this is recorded by Mr Eames. The parasites were examples of Tania angulata. Apart from the epidemiological aspects of the subject, it is not uninstructive to notice the variety of helminths that infest the common fowl and game birds. Accordingly, I append a similar but more extended list than that previously given in the supplement to my introductory treatise : Entozoa of game birds and the common fowl. * 1 iL cJ s-1 6" H 3 4 & s ! 1 & Monostoma verrucosum, Zeder... Distoma oxt/cepkalum, Kudolphi. oi'it/iuii, Rudolphi . . il il'it'ituin. Mi ram Filaria Mansoni, Cobbold Ascaris vesicularis, Froelich ... ,, aibbofctf Rudolphi * * ... * * ... * Spiroptera hamulosa, Diesing . . . Dispharagus nasutus, Dujardin . spiralis, Molin Slrongylus pergracilis, Cobbold Sclerostoma syngamus, Dicsing . Trichosoma longicolle, Kudolphi Tfenia malleus, Goeze * * * * * * cj'ilis, Dujardin ... . infundibuliformis, Goeze * * In regard to this list I can only afford space to remark that several of the species are possibly mere varieties. Some of the worms are of great interest. It occasionally happens that Distoma ovatum is found in the albumen of the fowl's egg, and it is even more common to obtain Ascaris inflexa from the same situation. For a recent example I am indebted to Dr Walker, of Peterborough. Spiroptera helicina resides in the feet, occa- sioning enlargement of the joints and consequent distress to the bearer. Probably the most important in the list is my Strongylus pergracilis. Here I may mention that on the 10th of April, 1878, I received a letter from Dr Manson, of Amoy, AVES 441 announcing his acquaintance with a filaria infesting the eye of the fowl. On the 9th of May I also received from Dr Manson the head of a bird showing examples of the worm. As the species is new to science I have proposed to call it Filaria Mansoni, after the discoverer. The male is f" and the female f ' in length. Of the injurious nematodes, giving rise to avian epizooty, probably one of the most destructive is Ascaris maculosa infesting pigeons. On the 9th of October, 1873, I received a letter from Dr J. Alexander Macdonald, of Woburn, Bedfordshire, stating that he had forwarded to me a pigeon which had been found dead on the previous morning. It seems that the owner of the bird had erected a large pigeon- house, and had imported a number of Antwerp smerles, these birds all continuing in a perfect state of health until about a week before the above-mentioned date, when, to use Dr Mac- donald' s words " first one and then another was attacked, and so on, until four or five of the pigeons had died after a few hours' illness." The suddenness of these attacks not unnatu- rally suggested poisoning ; and, accordingly, says my informant, the owner " had the curiosity to open one of the birds, when, to his astonishment, he found the intestines stuffed with worms." Two days later I received a letter from Dr Mac- donald, stating that several others of the flock had died, and it further appeared to him probable that the daily list of sick and dying would continue to increase. On the 14th of the month three more of the birds were dead. On the 4th of the follow- ing November, the same correspondent obligingly informed me that the epidemic had been "at last mastered." It seems that altogether twelve birds had perished. On the 9th of October one of the birds was carefully examined by me, and the results were so interesting that I am constrained to give a few of the particulars originally communicated to theZoological Society. As stated in my paper, the whole intestinal tract of the dead bird was crowded with these ascarides. The small intestine was inflamed throughout, and showed several large ulcerated patches ; never- theless, there were no traces of emaciation. From this it was evident that the parasites had grown quickly, the malady having a correspondingly rapid formation. The distribution of the parasites was curious. One specimen, two inches long, reached from the crop to the proventriculus. The cavities of this organ and of the gizzard were crammed with worms com- pletely blocking the passage. Three of the worms had also 442 PARASITES OF .ANIMALS placed themselves within the pyloric opening, their bodies partly lodging within the duodenum. The duodenum itself was crowded with worms, their numbers somewhat decreasing downwards. I removed thirty-six worms from the oesophagus, proventriculus, and stomach, besides 166 others from the intes- tinal canal, thus obtaining a total of no less than 202 nematodes from this small host. Considering the large size of these entozoa, the extent of infection must be pronounced remarkable. The largest females measured 2J" in length. One of the most interesting facts serving to exemplify a well-known habit of lumbricoid worms generally consisted in the circumstance that two of the parasites had succeeded in perforating the horny lining membrane of the gizzard. The injuries had been accomplished during the life of the host, for the walls of the gizzard were inflamed opposite the perforations. There was a little half digested food within the stomach, the debris of which, when placed under the microscope, showed several ova. There were no free embryos, neither had the development of the freed eggs proceeded beyond yelk-segmentation. Free eggs were also found both in the small and large intestine. The eggs measured about g^" by 7o5 " in diameter. Referring to my paper for further anatomical details, I can only add that, despite these facts, the ascarides in question do not appear to be a very frequent source of epizooty. It was remarked by Dujar- din that Heister, at Rostok, and Gebauer, at Breslau, found this parasite abundant at the beginning of the eighteenth century ; but, according to examinations conducted at Vienna, the worm was found in the common pigeon in only eleven instances out of 245, and thrice only in thirty-eight examples of the ring- dove ; moreover, the examination of eighty-seven other pigeons and doves of different species yielded entirely negative results. , The Dublin helminthologist, I Bellingham, noticed the occur- g|M4 VI / rence of this parasite in Ireland. V^ J^^r ^ n y a ^ em P* i so mu ch as to \ ^~" & '/ enumerate the species of nema- toids infesting birds would carry me far beyond the aim and scope ... ... of this treatise. One of the com- FIG. 74 Tail of the male Ascans vestculans. From a ring-necked pheasant. Original. monest Species IS AsCdTlS (Hete- ' rakis) vesicularis. Many hundreds of forms have been described by Dujardin, Diesing, Molin, Krabbe, and other systeinatists, AYES 443 and it remains for some future laborer to condense the facts which are dispersed throughout a very wide-spread literature. As regards the particular species of nematoids that are either actually known or conjectured to be injurious to birds I can only find space to repeat some of the particulars which I have else- where recorded in respect of Sclerostoma syngamus. In 1799 a letter from Dr Wiesenthal, of Baltimore, U.S., was published in the ' Medical and Physical Journal/ containing an account of a parasite infesting the trachea of fowls and turkeys in America. The communication is dated May 21st, 1797, and is the first public record concerning the entozoon. Dr Wiesenthal says : " There is a disease prevalent among the gallinaceous poultry in this country, called the gapes, which destroys eight -tenths of our fowls in many parts, and takes place in the greatest degree among the young turkeys and chickens bred upon old-established farms. Chicks and poults, in a few days after they are hatched, are found frequently to open their mouths wide and gasp for breath, at the same time frequently sneezing and attempting to swallow. At first the affection is slight, but gradually becomes more and more oppressive, and it ultimately destroys. Very few recover ; they languish, grow dispirited, droop, and die. It is generally known that these symptoms are occasioned by worms in the trachea. I have seen the whole [windpipe] completely filled with these worms, and have been astonished at the animals being capable of respiration under such circumstances." Any one who has witnessed the gapes will at once recognise the accuracy of Wiesenthal' s description ; and so far as the phenomena of the disease are concerned, very little more has been added in the numerous accounts which have since appeared. On the 1st of August, 1808, the English naturalist, George Montagu, communicated to the Wernerian Society a paper entitled " Account of a species of Fasciola which infests the trachea of poultry, with a mode of cure." Mon- tagu does not appear to have been aware of the existence of any previous record. He gave a scientific description of the parasite, which led to its being noticed in the systematic works of Rudolphi, Dujardin, and Diesing, but the best accounts of the worm are due to Von Siebold. Sclerostoma syngamus has been found in the trachea of the turkey, domestic cock, pheasant, partridge, black stork, magpie, hooded crow, green woodpecker, starling, and swift. In July, 1860, I obtained a fowl suffering from the gapes, and operated upon it in the 444 PARASITES OF ANIMALS following manner : A small portion of wool having been dipped in chloroform and placed in front of the nostrils the bird soon became insensible. The skin of the neck was then divided and the trachea slit up to the extent of a quarter of an inch. With a pair of common dissecting forceps, I removed seven Sclerostomata. Six of these parasites were sexually united, the odd worm being a female. After I had closed the external wound with a single thread the bird woke out of its artificial sleep, when it soon recovered its legs, and ran about the table vigorously. Moreover, in a very few minutes it devoured the contents of a saucer partly filled with bread and milk. An occasional gape was caused by an accumulation of frothy mucus within the injured trachea, but this obstruction the bird soon got rid of by shakes of the head and sneezing. The only sub- sequent inconvenience to the bird arose from emphysematous dis- tension of the cellular tissue of the head and neck. This was relieved by puncture, the emphysema ceasing to form after the external wound had healed. Some months afterwards I destroyed the bird, and on dissecting the neck, a distinct cicatrix was found indicating the site of the operation on the trachea. The divided cartilaginous rings, six in number, were united only by a thin layer of connective tissue. The female worms gave an average length of f", the males scarcely exceeding J". The mouth is furnished with six prominent chitinous lips. In both sexes the surface of the body is quite smooth, but the tail of the female exhibits a tendency to fold upon itself. The lower part of the body suddenly contracts to form a short, narrow, mucronate, pointed tail. The male is usually found rigidly affixed by means of a strong, membranous, sucker-like bursa, which proceeds from the lower end of its body. In regard to the peculiar mode of union of the sexes, it becomes an interesting point to ascertain whether there be an actual incorporation of the substance of the copulatory organs during or after the act of impregnation. In my specimens none of the three pairs were organically united, and I succeeded in separating one pair very readily. Dujardin speaks of them as being soldered together, whilst the statements of Von Siebold are still more explicit. In connection with this subject the latter observer makes the following comment (' Wiegmann's Archiv/ 1836, s. 106) : " The two sexes of almost all round worms are united only at the time of copulation. The male of Heteroura androphora has also the habit of remaining connected AYES 445 with its mate beyond the period of copulation ; here, thus, there is a continuous union of the sexes without a growing together ; and in Syngamus trachealis there is ultimately a lasting continuity of the sexes by means of an actual growing together." Having confidence in Yon Siebold's statement, I concluded that the sexual union in my specimens had only recently been effected. Admitting this to have been the case, one naturally asks how the mature eggs can make their escape. Clearly, the eggs can only escape by an eventual breaking up of the body of the parent. The eggs of Sclerostoma syngamus are com- paratively large, measuring ^' in length. Many of the ova contained fully formed embryos, and in the centre of the lower third of the body of one of them I perceived an undulating, imperfectly formed intestinal tube. By whatever mode the young escape the shell, it is clear that they are already suffi- ciently developed to undertake an active migration. A change of hosts is probably necessary, but in the first instance they either enter the substance of fungi or other vegetable matters, or they bury themselves in the soil at a short distance from the surface. In view of checking the destructive influences of this parasite, the following methods have been recommended. First. The simplest plan consists, as Dr Wiesenthal long ago pointed out, in stripping a feather from the tube to near the narrow end of the shaft, leaving only a few uninjured webs at the tip. The bird being secured, the webbed extremity of the feather is introduced into the windpipe. It is then twisted round a few times and withdrawn, when the worms are found attached. In some instances this plan succeeds entirely. Secondly. The above method is rendered more effectual when the feather is previously steeped in some medicated solution which will destroy the worms. Mr Bartlett employs salt for this purpose, or a weak infusion of tobacco ; and he informs me that the simple application of turpentine to the throat externally is sufficient to kill the worms. It should be borne in mind that the bird itself may be injuriously affected by these drugs if they are carelessly employed. Thirdly. The treatment recommended by Mr Montagu proved successful in his hands, although the infested birds were old partridges. One of his birds had died of suffocation ; but he tells us that " change of food and change of place, together with the infusion of rue and garlic, instead of plain water, to drink, and chiefly hemp-seed, independent of the green vege- 446 PARASITES OF ANIMALS tables which the grass plot of the menagerie afforded, recovered the others in a very short time/' Fourthly. The plan I employed in my experiment. This is only desirable in advanced cases, where suffocation is impend- ing. It will afford instant relief, as the trachea may be cleared of all parasitic obstructions. Lastly. The essential point to be observed is the total de- struction of the worms. This will help to put a stop to future epizootics. If the parasites are merely killed and thrown away carelessly, the eggs will sustain no injury. Decomposi- tion having set in, the young embryos will sooner or later escape their shells, migrate in the soil or elsewhere, and ulti- mately find their way into the air-passages of birds in the same manner as their parents did before them. In this place I must not omit to mention the remarkable cir- cumstance, quoted in my pamphlet on the grouse disease, that Prof. Wyman, of Boston, found Eustrongyli surrounding the cerebellum in seventeen out of nineteen snake-birds or water- turkeys that had been shot in Florida. These viviparous nematodes apparently occasion their avian bearers no inconveni- ence. No doubt, as Wyman observes, their presence must be regarded as a normal state of things : but should they occur in excessive numbers, then we can hardly doubt the result. As regards acanthocephalous parasites, although not so nume- rous as the nematodes, it is extremely probable that they play a similar role. Parasites which prove fatal to swine are scarcely likely to be harmless in birds. On the 18th of February, 1875, I received from Sir Joseph Hooker eleven worms for identification. Mr Charles P. Hooker, his son, subsequently informed me by letter that he had found them in a Redwing (Turdus iliacus) which he dissected in January, 1875. The worms (Echinorhynchus transversus) occupied the large intestine, probably to the number of one hundred in all. Hitherto this parasite has been found abundantly in the black- bird, thrush, and in most of the Turdida ; but not in the red- wing. It has also been obtained from the starling and red- breast. The presence of so many of these armed parasites in one small host could hardly fail to inflict severe injury on the bearer. In concluding this section of my work I can only find space to make a few acknowledgments. Most of the rare, new, or interesting avian entozoa which I have examined and described AVES 447 have been received either from the Zoological Gardens, or from personal friends. In particular I may mention the collections sent to me by Mr Charles Darwin, Mr Eobert Swinhoe, Mr Charles W. Devis, Dr Murie, Dr John Anderson, and Mr Spooner Hart, of Calcutta. A great many correspondents have contributed single specimens, many of which I have already incidentally acknowledged in these pages. In this place I must particularise the new species (Ascaris Cornelyi) which I described from specimens sent to Mr Sclater. This worm in- fests the vulturine pintado (Numida vulturina). Mr Darwin's collection contained fine examples of Filaria horrida from the American ostrich (Rhea). When dissecting birds at the Zoolo- gical Society's Menagerie, I obtained (in addition to the parasites already mentioned) Distoma oequale from the American owl (Strix perlata)-, Tcenia multiformis from the night heron (Ardea nyctocorax) ; T. infundibuliformis from a horned pheasant (Phasianus) ; T. laevis and T. lanceolata and also Ascaris tribothrioides from a dusky duck (Anas obscura) ; Eustrongylus papillosus (fig. 75) from the larus crane (Grus antigone) ; Trichosoma longicolle from the horned pheasant, and T. brevicolle from the Sandwich Island goose (Bernicla Sandwichensis). This bird was also infested by Spiroptera crassi- cauda and Ascaris dispar. From the ring-necked pheasant (Ph. torquatus) and from the black-backed Kaleege (Euplocomus melanotus), and also from a cheer pheasant (Ph. Wallichii), I obtained abund- ance of Ascaris vesicularis. From the ashy -headed S*ed Ml origmHf nl " goose (Chloephaga poliocephala) examples of Sir. tubifex and Sir. nodularis. This bird also yielded a new species (Sir. acuticudatus) . From a tinamou (Tinamus) I obtained the Ascaris strongylina of Rudolphi (Sir. spiculatus, mihi). From amongst our British birds I have obtained Asc. deprcssa, Tri- chosoma falconum and Hemistoma spathulum, from the kite (Falco milvus). Of these three worms, the last named was also found in the long-eared owl (Strix otus), whilst the first likewise occurred in a kestrel (Falco tiununculus] and in a honey buzzard (Pernis apivorus). I may add Filaria attenuata from a peregrine (F. peregrinus) ; and F. leptoptera from a sparrow hawk (Accipiter nisus). From the redshank (Totanus calidris) I obtained Tcenia variabilis, and from the curlew (Numenius arcuata) T. sphoerophora ; and from various gulls (Larus glaucus 448 PARASITES OF ANIMALS and L. tridactylus) the Tetrabothrium cylindraceum. Also from the grey gull Echinostoma spinulosum. From the red- throated diver I procured Tetr. macrocephalum. I found this tapeworm also in the guillemot (Uria troile), together with a nematode (Ascaris spiculigera) two examples of which were lodged in the right auricle of the heart. From a capercaillio (Tetrao urogallus) I have obtained a species of Ligula, and likewise numerous examples of Trichosoma longicolle. Of necessity, this brief notice only comprises a small part of the avian entozoa contained in my collection, many of which I have not had time to describe, whilst, as regards others, I can only say that they remain in abeyance for examination and identifi- cation. Mr Brotherston has recently recorded an interesting find (made Nov. 25th, 1874) of nematodes in the legs of the lesser grebe (Podiceps minor), and also (Feb. 27th, 1878) in the water- hen (Qallinula Moropus). Both limbs of both birds were in- fested. The worms of the grebe were spirally coiled amongst the muscles and tendons near the lower end of the tibia, and when unrolled measured about an inch in length. The para- sites of the waterhen were similar in appearance. Not impro- bably these were all sexually-imperfect female examples of Filaria acuta hitherto found in the abdomen of grebes. The British Museum contains many interesting specimens purchased from the collection of Von Siebold, but they are practically inaccessible to investigators. The entozoa in the Hunterian Collection, though few in number, are in an excellent state of preservation, and at all times accessible to visitors. The ectozoa of birds are too numerous to be dealt with in these pages. References to recent papers by Haller, Megnin, and Westwood will be found below. The insects infesting the domestic fowl have been alluded to in connection with the occurrence of poultry-lousiness in the horse. BIBLIOGRAPHY (No. 57). (Anonymous), "On the (gape) Diseases of Fowls," the ' Veterinarian/ p. 267, 1841. (Anon., initialed " Q."), Letter on the "Grouse Disease/' in the ' Times/ Sept. 5, 1874. (Anon.), " On Grouse and Partridge Disease/' being annotations in the ' Lancet/ Sept. 4, 1875, pp. 360 and 361. (Anon.), "Grouse Disease/' letter signed "R." (probably from Lord Ravensworth), in ' Land and Water/ Aug. 16, 1873. (Anon.), "Grouse Disease/' article (from " W. C.") in the 'Field/ Aug. 2, 1873 (criticising my brochure. T. S. C.). AVES 449 Arlong, " Note on Tsenia from the Fowl/' ' Rec. Med. Vet./ 1875. Baird, W., f ' Descr. of Ttenia calva from the Grouse/'' in ' Brit. Mus. Catalogue/ p. 83. Blavette, " Descr. of a Verminous Disease among Fowls/-* ' Veterinarian/ p. 649, 1840. Brother 'ston, A., " Parasitic Worms in Legs of Grebe (Podiceps minor] and Water-hen (Gallinula chloropus)," ' Science Gossip' for April, 1878, p. 88, and in ' Proceedings of the Berwickshire Naturalists' Club/ vol. viii, p. 288. Garter, B. (see Cobbold). Chapman, H. 0., fc Description of a new Tapeworm from Rhea," < Proceed. Phil. Acad./ 1876, p. U.Chatin, /., "Etude sur des helminthes nouveaux ou peu connus (treating of a Cyathostoma, from Anas tadorna and Sclerostoma pelecani)," ' Annales des Sciences Naturelles/ 1875. Cobbold, ' The Grouse Disease, a statement of facts tending to prove the Parasitic Origin of the Epidemic/ London, 1874. Idem, Letter in the ' Field/ Sept. 9, 1872. Idem, " Contributions to^our Knowledge of the Grouse Disease, with description of a new Species of Entozoon," ' Veterinarian/ March, 1873; see also an article (by Brudenell Carter) in the ' Times ' for Sept. 5, 1874; repr. in the 'Veter./ Oct., 1874. Idem, " Remarks on the Entozoa of the Common Fowl and of Game-birds, especially in relation to the Grouse Disease/' the ' Field/ Sept. 14, 1867, and < Brit. Assoc. Rep./ 1867. Idem, " On Sclerostoma and the Disease it occasions in Birds," ' Linn. Soc. Proc./ 1861 ; repr. in the 'Field/ June 22, 1861, and in ' Edin. Vet. Rev./ vol. iii, p. 439, 1861, also in Tegetmeier's work on ' Poultry / see also a comment on " Gapes/' by " Umbra/' in the ' Field/ June 29, 1861. Idem, " Parasites from the Zoological Gardens," ' Intel- lectual Observer,' 1862. Idem, " Notes on Entozoa (species Nos. 1, 7, 9, 12)," in 'Zool. Soc. Proc./ 1873-76. Idem, ' Linn. Soc. Trans./ 1858. Idem, " On Entozoa of Birds and Fishes, collected by Mr Charles W. Devis," ' Zool. Soc. Proc./ 1865. Idem, "Note on Entozoa in the Crested Grebe," the 'Field/ March 29, 18*73. Colquhoun, W., 'Remarks on the decrease of Grouse, and on the Grouse Disease (Gapes),' Edinburgh, li858 ; see also a notice in ' Edin. Vet. Rev./ vol. i, April, 1859. Crisp, E., " Note on Hydatids in an old Honduras Turkey," ' Path. Soc. Trans./ 1863. Idem, " On Sclerostoma," 'Rep. of Path. Soc./ in 'Med. Times and Gaz./ Oct. 26, 1876, p. 474. Idem, " Note on Filaria in the Heart of a Peregrine Falcon," ' Path. Soc. Trans./ 1854. Davaine, ' Syngame de la trachee/ p. 37, and 'Synops.' cxiv, in his ' Traite.' Devis, C. W. 29 450 PARASITES OF ANIMALS (see Cobbold). Diesing, ' Re vis. der Myzelminthen/ Abtheil. " Tremat.," 1858. Idem, " Tapeworm from Podiceps," in his 'Zwanzig Arten von Cephalocotyleen/ Wien, 1856. Idem, see various species in his ' Revisionen/ given in Bibl. No. 58. Eames, 0. J. L., " On Tapeworm in Blackbirds/' letter to the 'Lancet/ June 9, 1877, p. 863. Farquharson, R., "The Grouse Disease (due to a contagious fever)/' letter to the 'Lancet/ Sept., 1874. Fergusson, J., "On Grouse Disease/' letter in the ' Times/ July 16, 1878. Gentles, T. W., " Tape- worm in Birds," letter to the 'Lancet/ Jan. 18, 1868, p. 106. Holler, G., " Freyana und Picobia, zwei neue Milbengat- tungen," in ' Sieb. u. Koll. Zeitsch./ 1877, s. 181. Johnston, D., " On the Grouse Disease/' letter in the ' Lancet/ Sept. 20, 1873, p. 441. Krabbe, 'Bidrag til Kundskab om Fuglenes Baendelorme/ Copenhagen, 1869 (contains a summary in French, ' Recherches sur les Tenias des Oiseaux'). Linstow, 0. von, " Enthelminthologica " (containing descriptions and notes on worms from birds, fishes, reptiles, and mollusks), 'Archiv fiir Naturgeschichte/ 1877. Idem, "New Flukes (Dist. vitellatum and D. macrophallus) from Totanus hypoleucus, and D. calebs from Fringilla/' Beobacht. in 'Arch. f. Naturg., '1875, s. 189- 193. Maclagan, " Note on the Grouse Disease," ' Proc. Roy. Soc. of Edin./ April 20, 1874, p. 378. Marion, " Revis. des Nemat. du Golfe de Marseilles," ' Compt. Rendus/ 1875. Megnin, P., " On Harpirhynchus and other Mites," in ' Rev. f . Thierheilk./ Oct., 1878, s. 146. Idem, "Memoire sur les Chey- letides Parasites (Picobia, &c.)," ' Journ. d'Anat. et de Physiol./ 1878 ; see also 'Rev. f. Thierhielk./ Sept., 1878 et seq.Molin, in his various monographs (quoted in Bibl. Nos. 54, 56, and elsewhere). Montagu, G., "Account of a species of Fasciola which infests the Trachea of Poultry, with a mode of Cure," ' Memoirs of the Wernerian Nat. Hist. Soc./ vol. i, p. 194, 1811. Perrier, 'On Syngamus ' (brochure, Paris, 1875). Pulteney, R., " On Ascarides discovered in Pelicanus carbo and P. cristatus," 'Linn. Trans./ vol. v, 1800, p. 24. Roll, "Beitrag. zur Entwickelungsgeschichte der Taenien," ' Verh. d. Wiirzb. p. m. Ges./ Bd. iii, 1852, s. 51. Sanderson, J. B., " On Grouse Disease," 'Brit. Med. Journ./ May 15, 1875. Small, M., " Worms in the Eyes of Geese," from the ' Irish Farmer's Gaz./ in the 'Veterinarian/ 1862, p. 19. Tait, L., " Tapeworm in Birds," letters to the 'Lancet' for Jan. 25, 1868, p. 145, and Feb. 8, 1868, p. 214; see also "Pediculus," ibid., p. 180. BEPTIIJA 451 Tegetmeier, " On the Grouse Disease," in the f Field/ Sept. 12, 1874. Thick, " Letter on the Cure of Gapes/' in 'Land and Water/ Aug., 1867, p. W.Vaughan, "The Grouse Disease/' in the ' Field/ Aug. 23, 1873. Villow, A., "Sur les migrations, et les Metamorphoses des Trematodes," ' Comptes Kendus/ 1875, and < Ann. Nat. Hist./ 1875 (chiefly on flukes of the sea-lark, Tringa alpina). Idem, " Sur le syst. nerveau," &c., ibid., 1875. Idem, " On the Helm. Fauna of the Coast of Brittany (chiefly from birds)," f Ann. Nat. Hist./ from ' Comp. Eend./ 1875, p. 1098, and from < Arch, de Zool. Experim. et gen.,' 1875. Idem, " Sur 1'appareil des Trematodes (Dist. insigne)" ' Compt. Rend./ 1875. Wedl, K., ' Anatomische Beo- bachtungen ueber Trematoden/ Wien, 1858 (contains excellent descriptions of numerous flukes, chiefly from birds). Westwood, J. 0., "New Flea on a Fowl (Sarcopsillus)," ' Entom. Month. Mag./ xi, p. 246, 1875. Wiesenthal, A., "Account of a Parasite infesting the Trachea of Fowls and Turkeys in America," ' Med. and Phys. Journ./ vol. ii, p. 204, 1799. Wyman, " On Eustron- gyli within the Cranium of Water-Turkeys," ' Proc. Boston Nat. Hist. Soc./ 1868. Youatt, " On a Verminous Disease in Poultry " (being a letter to him), ' Veterinarian/ p. 648, 1840. Zeller, " On Leucochloridium," from ' Zeitsch. f . wissensch. Zool./ 1874, s. 564, and from ' Bibl. Univ. Bullet. Sci./ 1874, p. 366, in < Ann. Nat. Hist./ Feb., 1875. PAET II (REPTILIA). Much that I have advanced in respect of the parasitism of birds holds good in the case of reptiles. I cannot recapitulate. The saurians, ophidians, and chelonians are extensively infested, but in this respect the amphibian frogs, toads, and salamanders are probably the most victimised. If, on the one hand, com- paratively few tapeworms have been found in reptiles, it may, on the other hand, be said that the Echinorhynchi come into prominence, causing serious injury to reptilian hosts. Serpents and chameleons are particularly liable to have their lungs infested by acanthocephalous entozoa, these organs being also attacked by pentastomes. I have received evidence of fatal epizooty amongst chameleons from this source ; and I have been requested to suggest a remedy. To prevent outbreaks of entozoal disease is one thing ; to offer a radical cure when the 452 PARASITES OF ANIMALS parasites are firmly anchored within the pulmonary organs is quite another matter. As remarked in my f Entozoa/ the trematodes display a great partiality for batrachians, more than half a dozen different species of fluke being known to infest the common frog. Flukes are likewise tolerably abundant in the saurian and chelonian reptiles. I regret that I cannot find space so much as to enu- merate the species. As one would naturally expect, the frog has been exhaustively anatomised and examined for entozoa, and it was this creature that supplied Leuckart and Mecznikow with the materials which led to their well-known discovery and controversy respecting the development, dimorphism, and parthenogenetic phenomena exhibited by Ascaris nigrovenosa. I cannot give the facts in detail. Female examples of the worm live in the lungs of the frog. Their young, as embryos, pass into the damp earth and mud, where they grow up into sexually- mature forms different from the parent worms found in the frog. These free adult worms, male and female, produce rhabditiform embryos which present characters of their own and attain a certain stage of growth. At this stage they are conveyed into the lungs of the frog where they arrive at sexual maturity. As there are no male worms in the frog, it is probable that the embryos of these parasitic females are agamo- genetically produced by internal budding, the sexual influence of the free males being, as it were, continued onward without actual contact with the parasitic females. Amongst the interesting parasites of the frog one must also mention Amphi- stoma subclavaium and Polystoma inter gerrimum. The former worm resides in the large intestine and the latter in the urinary bladder. The larvas (Cercaria diplocotylea) of this amphistome reside in or upon the body of water-snails, and, like the cercarian larvae of polystoma, they are furnished with eyes. I state this fact on the authority of Pagenstecher ; and, since I cannot devote a special section to the entozoa of mollusks, I repeat, in part, the valuable results which Pagenstecher published many years back and which have a permanent value in relation to the origin of parasitic diseases resulting from flukes. In the memoir quoted below, Pagenstecher gives the following conclusions (Schlussbemerkungen) : " (a). The eggs of the trematoda vary in respect of size, form, and color, being either furnished or not with a lid, and accordingly distinguishable. In the mature condition they EEPTILIA 453 contain a ciliated or a non-ciliated embryo of unequal growth, this embryo partly increasing in size even after its birth. In various conceivable ways the eggs themselves, or the embryos which have quitted their shells, arrive in and upon the bodies of mollusks, where they are consequently found. In this situation the egg opens, or the ciliated covering decays, and the contained motionless germ which in itself offers no distinctive charac- ters having become free, grows into a nurse, or forms several nurses within itself. " (b). Whilst some of the trematodes display a highly organised nurse condition, others exhibit only a simple kind of germ-sac. Both forms, nevertheless, appear to occur in one and the same species, probably depending upon external causes. " (c). The organised nurses (or r edits, as they are termed) have a mouth and a strongly marked muscular oesophagus, which is continued into a short or prolonged, single, blind intestine, or the latter may be double. The expulsion of animals developed within them I have only seen to take place through an opening at the hinder extremity. Old rediaa lose their structure. I did not observe any vascular system. Tailed trematode larvas (Cercarice), as well as redise themselves, are developed within the redise, this variation of nurse-contents probably depending on the season. " (d). No independent new germ-sacs are developed within the simple unorganised germ-sacs (sporocysts), and only such trematode larvae as are capable of arriving at sexual maturity are furnished with special appendages. " (e). When the immature contents Of both nurse forms (i.e. of sporocysts and redise) are accidentally set free, and are situated within the organs of nutrition of the living host, then they appear prepared to develop .themselves anew into nurse forms ; and, moreover, cercarise whose development has not yet attained a definite stage and even their tails also appear to enjoy a similar capacity. Some nurses are likewise capable of multiplication by division and budding. " (/) Some germ-sacs have the property of developing within themselves cercaria-like larvae which are different from the true cercariae from whose body the development of a distoma may take place, while their single or double tail-like appendages in all cases develop anew into germ-sacs. To this class belong Bucephalus and Distoma duplicatum. " (g). All the cercaria at present known are destitute of 454 PARASITES OF ANIMALS eyes, but other forms of trematode Iarva9 are furnished with visual organs. Accordingly, I never found eyes in young distomata whilst they were in their last dwelling-place, but eyes are certainly present in the young forms of Polystoma and Amphistoma. The supposition that a spontaneous wandering is associated with eyes is not yet confirmed in my experience. " (h). As a means of distinguishing the different forms of Cercarias, amongst other indications, their places of dwelling may be useful, because each mollusk only harbors a limited number of species. Notwithstanding, Professor Filippi is in error if he believes that every species of mollusk carries only a single armed form of cercaria. A migration of the cercaria is indispensable to its perfection. " (i). Many larval trematodes form cysts round themselves, probably by means of a special organ of secretion, and also by the epidermis. Their future destiny necessitates this. The sporocysts apparently fulfil towards the larvae, which are deve- loped within them, a similar purpose, namely, a protection against the stomachal digestion of the new host. In the pupa condition the development of the larva, which has now thrown off the tail, makes greater or less progress, according as to whether it is surrounded by nourishment or not. In particular, while in this stage, the different kinds of hooks for migratory purposes make their appearance, always, without doubt, after the shedding of the skin. Other trematodes pass through this tail-less sexually-immature stage without any cyst. I have not yet seen any larval trematode forms which had been produced in sporocysts or rediae without appendages ; they appear to occur, nevertheless. " (k). As the larvse exist only in a few hosts and most of them dwell only in one species of animal so, also, the con- tinued progress towards sexual maturity only succeeds in the case of certain well-defined larval organisms, but the digestion of the cysts and liberation of the larvae may be accomplished in various animals. " (/). The armed Cercariae appear to be larvae of the spine- covered distomes of amphibia ; for, as examples, the Cercaria ornata becomes transformed into Distoma clavigerum, and C. armata into Distoma endolobum ; the Dist. duplicatum and Gere, diplocotylea are, apparently, the juvenile forms of Dist. cygnoides and Amphistoma subclavatum. The Dist. echiniferum of Paludina could neither be advanced in development in the EEPTILIA 455 frog or duck, nor could all the other larvae which I subjected to experiment be developed either in the green or brown frogs. " (m) . When young treinatodes arrive at the right place for their maturation, then the male generative structures develop before the female organs, and in the subsequent excess of egg production the form and structure of the animal becomes obliterated . ff (n). The yelk-molecules surrounding the germinal vesicle are not directly transformed into an embryo." As regards the acanthocephalous parasites of reptiles, I may observe that Echinorhynchus anthuris is very common in the lesser water newt (Lissotriton punctatus) . In the accompany- ing illustration (Fig. 76) I have represented the free ovarian FIG. IG.Eckinorhynckus anthuris. 1, Attached to the intestine; 2, specimen enlarged; 3, ovarian vesicle, including germs ; 4, germs in various stages ; 5, vesicle with germs more advanced; 6, 7, eggs in their capsules; 8, free egg. Original. egg-bearing bodies, the development of the ovum, and the adult worms. For anatomical details, however, I must refer to my earlier treatise ( f Entozoa/ p. 100 et seq.). Amongst the species of entozoa that were found by me at the Zoological Society's Menagerie I may mention Distoma coro- narium and Ascaris lineata, from the intestines of Alligator mississippiensis ; Dist. Boscii, from an American snake (Coluber)' an immature nernatode, from the heart of Coluber Blumen- bachii ; and Echinorhynchus inflexus, attached to the intestines of a snapping turtle (Chelydra serpentina). I may add that the 456 PARASITES OF ANIMALS lungs of the alligator also contained examples of Diesing's Petitastoma oxycephalum. An Egyptian hooded snake (Naia haje), which died at the Zoological Gardens in 1859, furnished a new species of pentastome (P. multicinctum) . Dr George Harley described and anatomised this worm with remarkable care. To Harley 's memoir Prof. Leuckart did ample justice in his work on the ' Pentastoma/ Several new species of reptilian entozoa have recently been described by Dr von Linstow ; and Dr Solger has found a new trichosome (T. recurvum) beneath the skin of a young crocodile (probably Croc, acutus). For further particulars I refer to the revised descriptions and additions by Diesing, Molin, Schneider, and other systematists. BIBLIOGRAPHY (No. 58). Baird, W., "Description of a new Entozoon from the Diamond Snake," in ' Proceed. Zool. Soc.' for 1865, p. 58, and in ' Ann. Nat. Hist/ for July, 1865, p. 52. Blanchardj " On Polystoma," ' Ann. des Sci. Nat./ 3e ser., viii, p. 331. Canton, E., " An account of some Parasites attached to the Conjunctivas of the Turtle's Eyes," ' Quart. Journ. Micr. Sci./ and ' Dublin Med. Press/ 1861 (with remarks by myself }. Colloid, 'Notes/ &c. (1. c., Bibl. No. 57), and in ' Linn. Trans./ 1857. Crisp, E., " Note on Cysticerci and Trichocephali from an Alligator," 'Path. Soc. Trans./ 1854. Diesiny, 'Revision der Cercarieen/ 1858; ' Re vis. der Myzel- minthen/ 1858; 'Nachtrage (u. s. w.)/ 1859; ( Re vis. der Nematoden/ 1860; ' Re vis. d. Turbellarien/ 1861; ' Re vis. d. Cephalocotyleen/ 1863. Idem, ' Monographic d. Gatt. Amphis- toma und Diplodiscus/ and 'Nachtrage zur Monog. der Aniph./ 1839. Dujardin, 'Hist. d. Helm/ (1. c., pp. 320, 526, &c.). Elerth, " On Myoryktes Weismanni from the Muscles of the Frog," trans, by Busk, from ' Siebold und Kolliker's Zeit- schrift/ in ' Lond. Micr. Journ./ Jan., ]864. Gastaldi, ' Cenni sopra alcuni nuovi Elmint./ Torino, 1854 (new flukes from frogs and salamanders). Gluge, "On Entozoa in the Vessels of Frogs," from ' Comptes Kendus/ in ' Micr. Journ. and Struct. Eec./ p. 207, 1842 ; see Griibe and Valentin. Grille, " On the Entozoa of the Frog, and on the Pathology of that Batrachian," from ' Comptes Rendus/ in ' Micr. Journ. and Struct. Rec./ p. 246, for 1842 ; see also Mandl. Harley, G., " On the Anatomy of a new Species of Pentastoma found in the Lung and Air-sac of an Egyptian Cobra," ' Proc. Zool. Soc./ June, part xxv, p. 115, 1857. Leuckart, ' Bau und Entwickelungsgeschichte der Pentastomen/ Leipsig, 1860. Linstow, ' Enthelurinth/ (1. c., PISCES 457 Bibl. No. 57). Macalister, A., "On the presence of certain Secreting Organs in Nematoidea/'' ' Ann. and Mag. of Nat. Hist/ for 1865. Idem, "On the Anatomy of Ascaris dactyluris" ' Proc. Nat. Hist. Soc. of Dublin/ vol. iv, I865.Mandl, "De- velopment of Entozoa (Ascaris nigrovenosa of the frog)," from ' Kep. of French Acad. of Sci./ in ' Month. Journ. of Med. Sci./ vol. ii, p. 1081, 1842. Molin, ( Monog. del gen. Myzelminth ; Mon. del gen. Physaloptera ; Mon. del gen. Histiocephalus ; Mon. del gen. Spiroptera ; ' Wien, 1859-60. Pagenstecher, ' Tre- matodenlarven und Trematoden/ Heidelberg, 1857. Sibbald, J., " On the Nematoideum natricis," ( Path. Soc. Trans.,' vol. viii, 1857. Solger, " Ueber eine neue species von Trichosoma," 'Arch, f. Naturg./ 1877. Valentin, "On Parasites in the Bladder of the Frog " (from ( Repertorium '), in ' Micr. Journ. and Struct. Eecord/ 1842, p. 183. Vogt, C., "On Filaria in the Vessels of the Frog," from ' Miiller's Archiv/ in ' Micr. Journ. and Struct. Eec./ p. 241, 184,2. Wedl, F., " Beitrage zur Lehre von den Haematozoen," ' Sitzungsb. Akad./ Wien, 1850 (from the blood of frogs, &c.).Zeller, E., " Weiterer Beitrag zur Kentniss der Polystomen," l Sieb. und Koll. Zeit- schrift/ 1875. PAET III (Piscis). Swarms of entozoa infest fishes, and it is hard to say whether they are less numerous in the inhabitants of fresh water than in those of salt water. More attention has been paid to the helminths of the fishes than to the internal parasites of birds and reptiles, consequently, the number of known species must be estimated by many hundreds. In like manner a great deal has been written respecting the ectozoa of fishes. These parasites, often called fish -lice, belong chiefly to the haustellated crustaceans, and are better known by the title of Epizoa. No account of them can be afforded in this treatise, but some trifling notice of the literature of the subject will be given below. About a hundred distinct species of fluke have been described as infesting fishes. Not many of these worms possess more than a zoological interest ; nevertheless, from that point of view certain types are very curious. Most of the species dwell in the stomach and intestines, but, as more or less remarkable exceptions, I may mention Distoma seriale infesting the kidney 458 PARASITES OF ANIMALS of Salmo umbla, D. longum (Leidy) from the pharynx of Esox estor, D. polymorphism from the urinary bladder of the common pike (Esox Indus), D. obesum from the gall bladder of Salminius and other Brazilian fishes (Xiphostoma, Leporinus), D. tornatum attached to the gills of Coryphana hippuris, D. rosaceum attached to the palate of Lota communis, and D. contortum attached to the gills of Orthagoriscus mola. Most of the forms found encysted are sexually-immature worms. To these belong D. annuligerum, found by Nordmann in cysts in the vitreous humour of the eye of the perch (Perca fluviatilis) , andD. embryo from the liver and peritoneum of Acerina vulgaris. One of the largest and most remarkable of the flukes inhabiting marine fishes is the Distoma clavatum, found by Tilesius in the stomach of Pelamys, by Pohl in Thynnus, and by Bosc in CorypJwena. In the last-named fish it has been found adhering to the gills, in the liver, and in the intestines. In August, 1865, 1 obtained this parasite from a sword-fish (Xiphias gladius), and in the same piscine host I also found examples of four other species of helminths (Tetrarhynchus attenuatus, scolex of another tetra- rhynch, Bothriocephalus plicatus, Ascaris incurva). Believing Distoma clavatum to represent several forms hitherto regarded as distinct, I append a few particulars respecting it. Five examples of this worm were obtained by me from the stomach of a sword- fish. Generally they varied in length from four lines to two inches. They differed somewhat in shape, but all had the so- called head and neck directed backwards. Below the ventral sucker the two largest specimens were distended with eggs and black pigment. All of them likewise exhibited more or less well-marked transverse rugae, the last ring surrounding an orifice which represented the outlet of a large contractile vesicle. The eggs averaged 8 Jo" in length. When revising the entozoa of the Museum of the Royal College of Surgeons I encountered many parasites without labels attached. Amongst these were several flukes, which, though differing from each other in size and shape, appeared to be identical. One of these specimens turned out to be the particular Distoma clavatum described and figured by Professor Owen in the 'Zoological Society's Transactions/ Several of the others I made out to be part of a series contributed by Mr George Bennett, who also gave specimens to the British Museum, but the College Museum stores contained yet a third group of specimens of uncertain history. The large fluke PISCES 459 described by Prof. Owen was formerly in the collection of the Rev. Lansdown Guilding. In Dr Baird's catalogue the specimens presented by Mr Bennett are stated to have come from the stomach of a bonito, and probably Mr Guilding' s specimens may be referred to the same " host." Be that as it may, the specimens differ from each other in a very striking manner. In the year 1 730 M. Garsin first described this worm under the generic title of Hirudinella. He says : " Get insecte tire de Festomac de la Bonite ne vecut qu' environ deux heures. Expose a Fair il etoit languissant, et reprenoit de la vivacite dans de Feau de mer. II diminua sensiblement de volume pendant qu'il vivoit encore." M. Garsin's description is accom- panied by three figures. His specimens do not appear to have exceeded \\" in length. In 1774 Pallas described a trematode (Fasciola ventricosa). It measured two inches in length. All that he says regarding its source is as follows : " Ex Amboyna missum fuit singulare hoc molluscum, quod ad aliud quam Fas- ciolarum genus referre non potui, in quo quasi gigas erit." He remarks upon its pale white color, and notices particularly the soft elastic body proper, which when wounded gave out a dark matter resembling soot. This material, when examined with the microscope, appeared fresh ; it was not the result of decom- position. Pallas also gives many other details, accompanied by a figure. In 1790 Menzies likewise described and figured a fluke about two inches long. He calls it Fasciola clavata : " It is of whitish color, somewhat pellucid, discharging at its mouth a black-colored fluid, which can easily be perceived through its body. I have often found it," he adds, " in the maws of the bonito, between the tropics in the Pacific Ocean." Notwithstanding the similarity of description, Menzies does not appear to have recognised the identity of his worm with that described by Pallas. Prof. Owen, however, subsequently estab- lished this identity, and referred to this species as the Fasciola clavata seu ventricosa. On the other hand, the British Museum Catalogue represents Pallas's worm as specifically distinct from that of Menzies, but as identical with the specimen described by Prof. Owen from Mr Guilding' s collection. In 1802 Bosc described and figured a trematode under the title of Fasciola fusca. This he obtained from the intestines of a dorado. In form it differs considerably from the fore- going species. Bosc's description runs as follows : " Brune, la partie posterieure tres-renflee, presque ovale, la partie 460 PARASITES OF ANIMALS anterieure mince, cylindrique, inegale, avec deux petits tcnta- cules en dessous. Le su9oir de Fanus tres grand." ]><>so recognised the identity of this worm with the Distoma coryplicncs of Rudolphi, and systematists generally have adopted his synonymy. In the British Museum Catalogue the Fasciola fusca and F. ventricosa of Pallas are regarded as one and the same species. The existence of two small tentacles is certainly peculiar. In 1827 Nardo obtained two very large flukes from the stomach of a fish captured in the Gulf of Venice during the month of September. He calls the fish Prostostegus prototypus t which appears to be the same as the Luvarus imperialis of Rafinesque. One of the parasites, being five inches in length, he named Distoma gigas. His description is as follows : "Distoma teres, rubrum, retractile; poro ventrali minimo cujus apertura magna, rotunda, ciliata ; poro antico terminali, parvo ; collo brevi, retrorsum divergente, extensili, apice angusto, basi lato ; cauda longa, postice incrassata et in apice obtusa oscula donata." The alleged ciliated character of the ventral sucker, was perhaps due to a wrinkled state of the lip. Apart from this character, I see no reason for supposing this parasite to be distinct from the Distoma clavatum procured by Mr Guilding, or the Fasciola ventricosa described by Pallas. The intestines of the fish harbored another parasite (D. Raynerianum) . Unfortunately, Nardo gives no figure of Distoma gigas. It is the longest fluke known to science. In the year 1835 Professor Owen communicated the memoirs already alluded to. In his paper he discussed questions relating to the structure of Distoma clavatum, and threw much light upon its anatomy, but I believe that the large t( lateral cavities " described by Owen are neither more or less than the somewhat unusually distended alimentary caeca. In 1845 Dujardin placed the worm with the true distomes, yet, at the same time, expressed grave doubts as to whether it were, in any sense, a fluke. " Ce ver," he remarks, " n'est certainement pas un distome ni meme un trematode. Si sa forme exterieure et ses deux oscules lui donnent quelque ressem- blance avec les distomes, sa structure musculeuse la rapproche davantage des Gordius, et son tegument ressemble a celui des siponcles." M. Dujardin examined the specimens preserved in the Paris Museum, and with regard to one particular example, described as " Fasciola, trouve dans la mer de Nice," PISCES 461 he says, it presents f{ une certaine analogie avec le pretendu Distoma clavatum." Dujardin himself was somewhat puzzled by the resemblance in question. He does not appear to have examined fresh specimens, yet he mentions the species as tolerably common in the bonito, and occasionally present in the tunny. At all events, it appears that the rightly so-called Distoma clavatum is not unfrequently taken from the ocean in the free state. In concluding my notice of this remarkable worm I can only add that after examining numerous speci- mens both in the fresh and preserved states, I have formed the opinion that the following specific names all refer to one and the same parasite : Distoma clavatum, Eudolphi ; D. cory- phoentp, Rud. ; D. gigas, Nardo ; Fas- ciola clavata, Menzies ; F. coryphcente, Bosc ; F. coryph. hippuridis and F. Scombri pelamidis, Tilesius ; F.fusca, Bosc; Hirudinella marina, Garsin ; H. clavata, Baird. In this list of syno- nyms we may probably also include Rudolphr 5 s Distoma tornatum. In addition to these distomes there are numerous piscine flukes which may fairly be relegated to other genera. Thus, provisionally, I ele- vated Dujardin's sub-genus Echino- stoma into a separate genus ; and on what I considered sufficient grounds I established several other new genera from amongst the more curious flukes that had been described as infesting fishes (Wedlia, Kollikeria). In the genus Echinostoma the oral sucker is either surrounded by a circle of little spines, or it occupies the centre of a disk, which is cleft at the ventral or anterior aspect. In the latter case the disk is either bordered both laterally and above by spines, or there are two large lobed appendages, whose margins are FIG. 77. Echinostoma Mspidum. Magnified. Original. 462 PARASITES OF ANIMALS furnished with spines. In other respects this genus nearly corresponds with the distomes, the simple digestive tubes bifurcating immediately below the cesophageal bulb. The speci- men of Ech. hispidum here drawn (Fig. 77) was taken by me from the spiral intestine of a sturgeon (1855), in which fish it occurs very abundantly. The figure represents a back view of the head and a lateral view of the body, the neck having been slightly twisted. The ventral sucker is concealed, but the transparency of the skin permits a view of the internal organs. Another remarkable genus, estab- lished by Von Siebold, is Gastero- stoma. In this genus the ventral sucker has taken the position usually assigned to the oral opening; the latter being near the centre of the body. The digestive caeca also dis- appear, leaving only a short sto- machal cavity, which reminds one of the same viscus in imperfectly or- ganised sporocysts or rediae. When O. gracilescens first came under my observation I followed Rudolphi in describing it as a distome (D. graci- lescens). The anatomy of the genus has been illustrated by Von Siebold ; from whose observations also it may be inferred that the larvae are various forms of Bucephali. Prof. Molin de- scribes the water- vascular or respi- ratory apparatus as consisting (in G. fimbriatum) of a broad central tube, occupying the entire length of the body and opening externally at the tail . Amongst the more remarkable fluke-types may be mentioned Van Beneden's Nematobothrium (N. fla- rina), occupying the branchial cavity of Scitena aquila, also Holostoma clavuSy found by Molin in the intes- tines of Gadus merlucius, also KolliTferia filicollis, occupying 1'iG. 78. Gastfrostoma graciltscens. Magnified. Original. PISCES 463 open follicles in the branchial cavity of Brama Raii. The sexes in the last-named genus are distinct ; male and female worms together occupying each cyst. The genus Monostoma is also largely represented amongst fishes. Prof. Wedl found a species (M. Wedlii) occupying follicles in the intestinal mucous mem- brane, and also adhering to the fin rays of Rhombus laevis. I also found a species (M. dubium) in a cyst attached to the ovary of Gasterosteus spinachii. Several species of amphisto- matoid worms were found by Natterer in Brazilian fishes (Cataphractus, &c.), some of these representing distinct genera (Aspidocotylus, Notocotylus) , to which I found Sonsino's remark- able fluke (Gastrodiscus Sonsinonis, mihi) from the horse to be very closely allied. In this connection must also be men- tioned Griibe and Wagener's curious Amphiptyches urna, found attached to the branchiae, and also in the intestines of Chimaera monstrosa. In addition to the above families and genera of digenetic flukes infesting fishes we have the monogenetic tristomes and poly- stomes. As remarked in my introductory treatise, the Tristo- midas display a leech-like aspect, in consequence of which they have been placed either along with the Malacobdellida, or in some other allied family of the suctorial annelids. The tris- tomes are not strictly entozoa, yet their internal organisation conforms more to the Trematoda than to the Hirudinidce. Thus, they support two small suckers anteriorly and one large sucker posteriorly, the body being externally smooth and devoid of annulations. The tristomes have therefore no anus. In some species the large caudal sucker is sessile, in others it is stalked or pedunculated, being in either case bordered by a membranous fold (Dujardin). All the species are hermaphroditic. They attach themselves to the gills of fishes or to the general surface, selecting especially the neighbourhood of the fins. Some species are parasitic on crustacean parasites that are themselves attached to marine fishes. In the genus Udonella the mode of develop- ment is known to be simple and direct. According to Van Beneden, the embryos are large and acquire the form and characters of their parents whilst they are still within the egg- shell. They are ready to assume an independent existence the moment they quit the shell. The eggs are oval, the chorion being prolonged into a single filamentary process or " holdfast/' Van Beneden compares a group of them to a " bouquet of vorti- cells," On quitting the shell the embryonic Udonella at once 40 i PARASITES OF ANIMALS attaches itself to the Caligus, and there acquires the adult con- dition. The Polystomida comprise a variety of remarkable genera. I accept this family as the equivalent of Dujardin's first group of trematodes which he termed " Onchobothriens," rejecting only his genus Diporpa, which is a juvenile condition of Diplozoon. In this family Van Beneden includes the genera Calceostoma and G-yrodactylus. In all the polystomes we have a more or less ramified intestine, but the reproductive organs conform to the general trematode type. All are hermaphroditic, the eggs being supplied with filamentary appendages, in some only at one pole of the shell, in others at both ends. The water-vascular system is conspicuously developed. All the species are supplied with prehensile hooks. In the Diporpa condition of Diplozoon there are two super- numerary hooks, associated with a dorsal sucker at the centre of the body, and it is by means of these organs that a conjugation between two such juvenile forms is effected. These two indi- viduals become organically united for life, after the fashion of the Siamese twins. After conjugation the sexual organs appear. In Onchotyle appendiculata the lower end of the body merges into a curious appendage, which is placed almost at a right angle with the body itself, and in this way, as Van Beneden justly remarks, the entire animal resembles a little hammer, the resemblance being very much heightened by the circumstance that one end of the appendage is cleft so as to correspond, as it were, with the notch which we employ in the action of nail-draw- ing. The Onchotyle appendiculata was first discovered by Kuhn attached to the gills of a dog-fish (8cillium catulus), but it has since been found ectoparasitically lodged upon other marine fishes. With the Gyrodactylidce I include Van Beneden's genus Calceostoma. The gyrodactyles have been classed with the Polystomidae. Amongst the characters standing out most prominently are those having reference to peculiar hooks which project from the great sucking disk. In Calceostoma this mechanism is reduced to a single horny structure placed at the margin of the caudal sucker in the central line. In some Gyrodactyli the hooks are very numerous. In Gyrodactyht* elegans the caudal sucker supports a pair of large laterally- curved hooks, which are placed back to back in the centre of the disk, being connected at their upper ends by a supple- mentary semi-lunar bar. A series of tentacles serve to increase the prehensile action of the sucker. In many species the males PISCES 465 are supplied with accessory horny developments. The genus Gyrodactylus has been studied by Nordmann, Von Siebold, G. Wagener, Yan Beneden, and especially by Wedl, who records the following results : (a.) " Gyrodactylus is found on the gills of fresh- water fishes under numerous specific forms, G. elegans being also found by Creplin and Siebold on the fins. Moreover, as I have found nearly every species of fish supporting a particular gyro- dactyle representative, it would seem that each finny creature supplies its own Gyrodactylus. Sometimes two of them are parasitic upon the same gill, being frequently associated with Trichodina, as well as with the still unintelligible Psorospermia. (b.) The clasping apparatus at the pos- terior end of the body must in an animal so soft and constantly ex- posed to the passage of regular currents be comparatively strongly developed and accommodated to the peculiar dwelling-places, and pro- bably the varying character of the latter supplies a reason why there should be so great a difference in the mechanism of the hooks belong- ing to the disk, (c.) The hooked apparatus affords a very valuable and mathematically precise means of diagnosis in the determination Of Species. This differentiation FIG. 7?. Gyrodactylus elegans, containing . an embryo, a, a, (Esophagus; a, testis ; inaV be accomplished by Observing h, h, sucker ; i, i, large hooks ; I, spines. J J Magnified. After Van Benedeu. whether there are two or four large hooks ; whether there be one or two connecting portions, and by noticing their several forms and relations to one another ; and whether, again, there are booklets or not, remarking in the first instance their position, form, distribution, and so forth. (d.) The integument is sometimes wrinkled transversely, at other times appearing to be smooth. (e.) The muscular apparatus is, in certain cases, very strongly developed. In the majority of instances special muscles are inserted into the 30 466 PARASITES OF ANIMALS handles of the hooks, and they are also very frequently directed into the transverse muscles of the skin. In Gyrodactylus cras- siusculus we find a protrusor penis and retractor palparum medius. (/.) Except in the case of G. elegans, four so-called eye- spots are observed at the anterior extremity of all Gyro- dactyli. As Siebold sayp, they answer the purpose of light- refracting organs. The palpi, which in G. crassiusculus are seen to contain muscular bundles, appear to be retractile touch- organs, extending more or less prominently forward. (g.) Observations in regard to the alimentary canal are at present incomplete, for only in the case of G. cochlea did I find a single gullet demonstrable, (h.) Gyrodactylus becomes sexu- ally developed, and cannot be regarded merely as a kind of ' nurse/ " So much for Wedl, whose views I have elsewhere recorded at great length. The genetic relations subsisting amongst the Gyrodactyles have given rise to much controversy. Observing the singular mode of reproduction in G. elegans, Von Siebold arrived at the conclusion that Gyrodactyles in general were only nurse-forms of some higher organism, and he pointed out, with undeniable accuracy, all the birth-stages of the young one as it apparently pullulated within the parent and sub- sequently emerged an almost perfect Gyrodactyle. Von Siebold also remarked that the so-called " daughter," at the time of birth, nearly equalled the " parent " in respect of size, whilst, moreover, it contained within its interior another very young Gyrodactyle, or, in other words, a " grand-daughter." Van Beneden interpreted these facts very differently. I have myself noticed the second generation, or daughter, to contain in its interior evidences of a third generation. This I observed in specimens obtained from the tails of Gasterostei caught in the Serpentine, Regent's Park. Indications of the third progeny were seen whilst the daughter still resided within the body of the nurse-parent, and the so-called grand-daughter became much larger immediately after birth. In one instance the " daughter " commenced showing herself by a slight bulging at the centre of the parent's body, whilst the integument of the latter yielded on all sides of the bud-like projection, and in such a manner as to convey the idea of a vaginal opening. There was an evident struggle on the part of the young one to free itself from the so-called parent envelope, but the tissues showed no signs of injury. On partial protrusion it was seen PISCES 467 that the budding portion corresponded with the centre of the daughter's body, and this, in a little while, assumed the aspect o a semicircular band. Subsequently the upper end became detached, the freed extremity being now recognised as the head. An interval elapsed before the broad posterior end of the animal could be disengaged, but immediately after this was effected the sides of the parent envelope closed in upon the opening, and all that remained was a small cavity or sac, indicating the position recently occupied by the daughter. Altogether the process occupied about five minutes. I care- fully compared the so-called " parent " with the " daughter/' but in regard to sige I can scarcely say which was the larger of the two. As before hinted, Van Beneden demurs altogether to Yon Siebold's views. He does not admit the parent to be a kind of " nurse," he does not consider the primary young one to be a "daughter," and, consequently, he does not regard the embryo seen within the latter as a "grand-daughter." Yan Beneden says : " According to our researches there is here a false interpretation ; the little daughter is lodged within the side of its pretended mother, and not in its interior ; instead of being its mother, it is its sister; there is a difference of shape because there is a difference of age ; the Gyrodactyles are vivi- parous, and as among the Trematodes the eggs are formed one by one, one embryo is scarcely formed when another commences its evolution, and the egg- deposition is effected even whilst the embryo is being produced, i The Gyrodactyles are therefore viviparous worms, which beget a single embryo at a time, as those of the trematode group, to which they are allied, beget a single egg at a time, and before the first embryo is expelled another is already partly developed. There, we believe, lies the correct interpretation of that phenomenon ; instead of a bud it is an embryo, which has escaped from an egg.. Here, therefore, we have no phemonenon of alternate generation or of digenesis, as Yon Siebold supposes, but a simple viviparous reproduction." Passing on to notice the cestodes of fishes, I may remark i that they often display characters very distinctive from those inhabiting birds and mammals, being commonly furnished with special tentacular hook-appendages employed as supplementary organs of boring and anchorage. In the cartilaginous sharks and rays these cestodes are remarkably abundant, and in certain osseous species they are scarcely less frequent. The only noteworthy kinds of fish which are commonly free from the 468 PARASITES OF ANTMALS invasion of tapeworms are the sturgeons, blennies, gobios, mullets, sparoids, and Sciaense. Some few of them are infested by Ligula, Caryophyll&i, &c. Cuttle fishes harbor a great variety of tapeworm-larvae, forming one of the chief sources whence sharks and rays obtain the same parasites destined to arrive at sexual maturity within their own bodies. Among the most interesting cestodes of fishes we may reckon the pit-headed tapeworms and their allies (Bothriocephalidae). One of the most common species is Both, proboscideus which FIG. 80. Section of the strobile of Botkriocephatiu proloscideus. Magnified. After Busk. is found, often in considerable numbers, lodged within the pyloric appendages of the salmon (Salmo salar and 8. hucho). It acquires a length of two feet. When in large numbers it cannot fail to prove injurious to the bearer. In this connection also must be mentioned B. nodosus. In the adult state this worm infests a great variety of water-birds (herons, PISCES 469 gulls, and divers), but in the young or sexually-immature taenioid condition it is a frequent inhabitant of sticklebacks (Gastereosteus aculeatus and G. pungitus), being also found in the salmon and in the bull-head, or father-lasher (Coitus scorpio). The immature tapeworm was formerly considered a separate species (B. solidus). Some years back Creplin dis- covered the connection subsisting between the two forms, and re-described the species in its two conditions under the name of Schistocephalus dimorphus, but it was reserved for Von Siebold to explain the full nature of this relationship. In his essay on " Tape and Cystic Worms " he shows that it is not until the worm reaches the intestine of the ultimate host that its segments acquire sexual completeness. As Yon Siebold observes, "the extent of development in each individual will be found to be in proportion to the time the parasite has passed in the bird's alimentary canal after its passive immigration." A similar instance, it is added, " occurs in the case of the Ligula simplicissima } infesting the abdominal cavity of various species of carp, whose sexual organs are, and remain, undeveloped as long as the worm resides within the fish; whilst, when the latter is eaten by ducks, divers, waders, and other water-fowl, the entozoon being thus conveyed into their intestine, it attains perfect sexual development. In the older helmintho- logical works the sexually- mature Ligula simplicissima is described under various specific names (L. sparsa, L. uniserialis, L. alternans, L. interrupta) ." These results have been con- firmed by later observers, but it is now usual to recognise the sexually-mature worm as the Ligula monogramma of Creplin. In 1876 Dr Duchamp published his beautiful memoir on this subject, treating the entire question exhaustively and adding important experimental details. M. Duchamp gives a list of about twenty species of fish that are infested by the immature worm, and amongst these the Cyprinidce play by far the most conspicuous part. M. Duchamp has recorded a fatal piscine epizooty amongst tenches (Tinea vulgaris), occurring in the ponds of La Bresse. This is produced by Ligula simplicissima, which escapes by an aperture formed near the vent of the infested fish. M. Duchamp also gives important anatomical and embryological details, but the especially interesting part of his memoir refers to his feeding experiments, seven in number. He succeeded in rearing L. monogramma in the domestic duck, by feeding this bird with examples of L. simpli- 470 PARASITES OF ANIMALS cissima obtained from the abdomen of the tench (Tinea vulgaris). The interest of these experiments does not cease here, since they afford a probable clue to the source of human BotkriocepKali, which in nearly all essential points of structure correspond with the Ligules. As remarked in the first part of this work, Leuckart long ago pointed to the Salmonidae as probably furnishing the intermediate host of this worm ; and he dis- proved the views of Knoch, of Petersburg, who thought he had reared Bofhriocephalus latus in the dog in a direct manner. I have already called attention to the opinion of Dr Fock, of Utrecht, who thinks the human bearer may become infested by the consumption of the little fresh-water bleak (Leuci.^ <.-< alburnus). From the observations of Dr Bertolus, it is extremely probable that our Bothriocephalus latus is the sexually- mature condition of Ligula nodosa infesting the abdo- minal cavity and pyloric appendages of the common trout (Salmo trutta). Another cestode of general interest is the Tricuspidaria (Trianophorus) nodulosus, infesting many of our fresh- water fishes. It varies in length from one to two feet. The seg- mentation of the strobila is very indistinct, but the reproductive organs occur at regular intervals. All parts of the body are extremely contractile, especially the head. The tricuspid hooks support thin chitinous laminae, which connect the two lateral horns of each hook to the central apophysis. The object of this arrangement is to afford additional security to the prong- like processes. Van Beneden appears to think it an error that the cusps of the hooks should have been figured in ' Kegne Animal ' as directed forwards, and he has drawn the hooks with the points downwards. In regard to the calcareous cor- puscles, narrow vessels may be easily recognised passing off continuously from the capsules in closing the particles. These vascular prolongations are single, having their course directed towards the epidermis ; doubtless they open at the surface, but I did not detect any aperture. I have figured the tubes in my f Entozoa ' (p. 132). Dr Guido Wagener figures similar structures as occurring in Cercaria macrocerca. Various species of Tetrarhynchus dwell in the bodies of sharks and rays, whilst their larvae inhabit fishes on which the plagiostomi feed. Immature tetrarhynchs occur in cuttle-fishes, but they are most abundant in such fish as the cod, haddock, turbot, whiting (Fig. 81), flounder, sole, gurnard, mackerel, PISCES 471 mullet, and conger-eel. A taenioid scolex constantly infests the muscles and viscera of the great sunfish. The tetrarhynchs differ from one another as regards the form of their proboscides and the relative number and disposition of the hooks. I must refer to my ' Bntozoa ' for a full description, with figures, of a larval tetrarhynch from the wall of the intestine of a haddock. Some Tetrarhynchi exhibit a very complex armature, as may be seen in Tetrarliynchus longicollis infesting the tope or penny dog-fish (Galeus vulgaris}. In this species the hooks are uniform in size, and arranged in spirally disposed circles car- rying from twenty to thirty hooks each. In the tetrarhynch from the whiting the hooks show much irregularity both as regards size and arrangement. A remarkable scolex in- fests the sun-fish (Orthagoriscus mola) ; it is a true tetrarhynch, but has been variously classed. According to my view all the follow- ing titles refer to this parasite : Gymnorhyn- chus reptans, Eudolphi ; G. horridus, John Goodsir ; Acanthorhynchus reptans, Diesing ; Bothriorhynchus continuus, Van Lidth de Jeude ; Bothriocephalus patulus, Leuckart ; Acanthocephalus elongatus, Rudolphi ; A. macrourus, Bremser ; Floriceps saccatus, Cuvier ; F. elongatus, Blainville ; Scolex gigas, Cuvier ; Tetrarhynchus reptans, Cobbold. Five or six examples of the sunfish have been examined by me in the fresh state, all of them being infested by tetra- rhynchs. In the fish here drawn (fig. 82) the liver and lateral muscles were extensively tunnelled by the parasite. In all instances the anterior part of the worm was found surrounded by a thick, clear, transparent cyst, which gradually diminished in thickness towards the tail. When liberated from its investing capsule the head of the worm presents a quadrilateral figure, each lateral half being furnished with a bipartite facet. The retractile boring organs are club-shaped, each supporting about 1600 hooks. Nearly all the hooks display a uniform length and thickness, but at the lower part of each proboscis there are two conspicuous circles, the hooks of which are at least twice as large as the others. The joints of the immature strobile are well formed, but exhibit no trace of sexual organs. If it be G. 81. -Portion of the proboscis of a scolex of Tetrarhynchus infest- ing Merlangus vulgaris. Magnified. After Busk. 472 PARASITES OF ANIMALS asked " what is the object of this perpetual tunnelling/' and " does the boring cause suffering to the host," I reply : " The object of tunnelling is apparently twofold ; first, that the parasite may constantly obtain fresh nourishment ; and secondly, that it may acquire another residence." It furnishes an example of a parasite perpetually striving to perform an act which it cannot accomplish ; for, in order to arrive at sexual maturity, it must wait until the sunfish is devoured by a shark. In regard to the question as to the boring action giving rise to pain, one cannot, of course, speak with absolute certainty. When there are many parasites occupying the liver, or other important viscera, then, doubtless, they create pain, and cause decay of the organs infested ; thus they enfeeble the vital powers of the host. At such a time the sunfish would be easily overcome by its natural enemies, and be the first to succumb in the struggle for existence. These wandering tetrarhynchoid scolices never escape the body of the inter- mediate host until they are passively transferred into the alimentary canal of the ultimate entertainer. In the sharks and rays they acquire sexual maturity. From these animals the proglottides pass into the water in the ordinary way. The ova are subsequently swallowed by sunfishes and other inter- mediate hosts, within whose stomachs the six-hooked embryos are liberated, and the scolices become developed in the ordi- nary manner. As obtains in Cysticercus fasciolaris of the mouse the scolex of Tetr. reptans becomes taenioid. I have seen the liver of an adult sunfish so infested by these para- sites that the whole organ might be fitly described as a mere bag of worms, the immature strobiles being inextricably coiled together and defying separation. One of the parasites which I removed from this particular fish is preserved in the Hunterian Collection. In reference to the nematoids of fishes I can say but little. They are excessively abundant ; sexually-immature filariaa being found in almost every marine fish that one examines. Even at our dinner and breakfast tables nothing is more common than to observe the little Filaria piscium spirally coiled within the tissues of herrings, -haddocks, cod-fish, and whiting. All the sexually-immature nematoids are, as it were, waiting to be passively transferred to their ultimate hosts. These final bearers are usually either fishes, birds, cetacea, or seals. Amongst fresh-water fishes the Cuc.ullanida play an FIG. 8Z.Tetrarhynckus reptans. I, Reduced figure of a sunfish, showing the worms in situ; 2, head ot a worm in its capsule ; 3, tsenioid scolex ; 4, section of the immature strobile ; 6, proboscis ; 6, row of hooks ; 7, 8, large and small hooks (magnified 260 diameters) ; 9, head of the scolex viewed from above. Original. 474 PARASITES OF ANIMALS important role. These parasites closely resemble the strongy- loid Sclerostomata, but the absence of a true bursa seems to justify their separation into a distinct family. In most of them the body is truncated in front and much narrowed or drawn out posteriorly. The head is broad and globular, and furnished with a powerful muscular pharynx. The mouth is seldom round ; it is often subterminal, opening by a transverse slit. The tail of the male is recurved, and usually supplied with membranous winged appendages ; sometimes there is a pre- anal sucking disk. In the female the tail is simple, and more or less sharply pointed. FIG. W.Cuctillanus forcolatus. Female. From the plaice (Platessa tulgar'u). Magnified. After Busk. The facts relating to the development of these parasites are especially interesting as having afforded Leuckart and Fed- schenko a clue to what obtains in the guinea-worm (Dracun- culus). The Cucullanus of the perch (G. elegans) is a vivipa- rous species. The embryos are supplied with little boring teeth, or styles, which enable them to perforate the bodies of entomostracous crustaceans. Having in a direct manner gained access to the perivisceral cavity of Cyclops, they remain coiled within the intermediate bearer until it has been pursued, captured, and transferred to the stomach of the ultimate or piscine host. Once liberated within the stomach of the fish the young Cucullani soon acquire sexual maturity. The acanthocephalous Echinorhynchi are very abundant in fishes. They also, like the Cucullani, require a change of PISCES 475 hosts in order to ensure the continuance of the species. No less than six species of Echinorhynchi are known to infest the trout (Salmo fario). As many as four species likewise infest the eel (Anguilla) ; the same number of distinct forms being also found in the turbot (Rhombus) and ling (Lota), whilst three species may be met with in the common sole (Solea). What we at present know respecting the mode of development of Echinorhynchi infesting fishes is principally due to the researches of Leuckart. Some years back Dr Guido Wagener FIG. 84. 1, Echinorhynchus angustatus (natural size and enlarged) ; 2, Echinorhynchut nodulosus (natural size and enlarged), with (3) two eggs (magnified 1000 diameters). Both species from a trout. After Busk. supplied admirable illustrations of the eggs and embryos of Echinorhynchi, but he was erroneously led to conclude that the larvas were developed in a direct manner. The notion of a simple metamorphosis was entirely disproved by the experi- ments of Leuckart, who found the growth and development of the young to be accompanied by a true alternate generation. He showed this to obtain in Echinorhynchus proteus, a species abundant in the trout and in many other fresh- water fishes. The 470 PARASITES OP ANIMALS embryo of this parasite is broad and obliquely truncated at the ventral surface anteriorly, being gradually narrowed to a blunt point posteriorly, and at the front part, on each side of the middle line, there are five or six spines biserially disposed. Similar characters are seen in E. filicollis. Prof. Leuckart introduced a number of eggs into a vessel of water con- taining several small crustaceans (Gammarus Pulex). These little animals readily swallowed the ova, and in a few days the embryos were found emerging from their shells, boring their way through the intestinal walls, then passing into the general cavity of the body, and even into the appendages themselves. During the next fourteen days the embryos within the Gammari exhibited an increase of size ; and in course of the third week a further metamorphosis caused the embryos to assume the readily recognisable characters of a young Echinorhynchus. Thus, in Leuckart's own words, " the ultimate animal arises in the interior of the primordial body, by a process which presents BO close an analogy with the production of an embryo, and, consequently, with the act of generation, that one feels inclined at once to identify it with such an act, and therefore, also, to regard the Echinorhynchus as exhibiting an alternation of generation in its mode of development rather than a metamor- phosis/' The young Echinorhynchus afterwards grows rapidly, its several internal organs, proboscideal sac, and muscular apparatus, gradually coming into view. At last the young entozoon com- pletely fills the interior of the embryo, the latter having scarcely undergone any change, and still remaining, of course, within its crustacean host. What may be regarded as even more extra- ordinary is the circumstance that the embryonic body next becomes firmly adherent to the young Echinorhynchus, thus ultimately forming the true integument of the adult Echinorhyn- chus. The original skin of the embryo, however, is cast off " as soon as the Echinorhynchus occupies the whole interior of the embryo." After this the sexual differences become clearly established. Leuckart remarks that the passage of the young Echinorhynchi into their ultimate host is probably unattended by any striking changes, whilst the metamorphosis of the embryo, as thus far detailed, occupies a period of about six weeks. In general the crustacean hosts appear to suffer little from the borings of the embryo parasites, but when the latter have assumed the Echinorhynchus - condition and happen to be PISCES * 477 particularly numerous they not unfrequently prove fatal to the unsuspecting Gammari. After their transference to the intestine of the ultimate host a period of about one week more is required for the completion of their development. From the large number of species of Echinorhynchi infesting our fresh-water fishes, they present quite a feature of piscine parasitism. Almost every perch, chub, carp, pike, barbel, bream, or roach that one opens is found to have its intestines occupied by parasites which exhibit a light yellow color. These are Echinorhynchi, the common forms being E. proteus, E. angus- tatus (Fig. 84, No. 1), E. clavceceps, E. globulosus, and E. tuberosus. In the Salmonidae, besides several of the above, we may also find E. clavula, E. fusiformis, and E. pachysomus. As a group these parasites are more attractive looking than most other helminths, and they will well repay the zoological collector. The species infesting marine fishes are almost as numerous as those found in fresh-water hosts. BIBLIOGKAPHY (No. 59). (Anonymous), " Note by ' An In- quirer ' respecting Worms in Fish," in the ' Lancet/ March 7, 1868, p. 336. Baer, K. E. von, " On the Tapeworms found in the Waters of the Pregel by Linneus," from the German, in ' Edin. New. Phil. Journ./ 1829, p. 374, and in the ' Edin. Nat. and Geo. Sci. Journ./ 1829-30, p. 3J1 ; also from the ' Trans, of Nat. Soc. of Dantzig/ in the ' Lancet/ 1829. Badcock; see Slack. Baird, ' British Entomostraca/ London, 1850. Beneden, J. P. van, " Les vers cestoides," f Mem. de FAcad. Roy. de Belg./ torn, xxv, 1850. Idem, ' Mem. sur les vers intest./ Paris, 1858. Idem, " On Echinobothrium," in ' Bull, de TAcad. de Brux./ 1849. Idem, (with Hesse), ( Rech. sur les Bdellodes ou Hirudinees et les Trematodes marins/ 1863-65. Idem, ( Rech. sur les Turbel- laries/ 1861. Idem, "On a new Lerneonema/' ' Bull./ 1. c., 1851, and in f L'Institut/ 1851. Bertolus, ' Mem. sur le deve- loppement du Dibothrium latum (Bothriocephale de Phomme)/ App. to Dr Duchamp's work quoted below. Bosc, ' Hist. Nat. des Vers/ 1802, p. 271. Bradley, G. L., "On the occurrence of Gyrodactylus on Sticklebacks/' ' Proc. Linn. Soc./ 1861. Brulle, " Note on the Reproduction of Ligula," from ' Comptes Rendus/ in 'Ann. Nat. Hist./ 1855Chatin, ' On Amphibdella torpedinis from the Gills' (1. c., Bibl. No. 57). Chavannes, " On Fluke-larvae from Coregonus/' in ' Bull, de la Soc. Yaud. des Sci. nat./ torn. iii. Claparede, E., " Ueber die Gattung Tetracotyle," &c., in ' Zeitsch. f. wiss. Zool./ 1857, s. 99 et 478 PARASITES OP ANIMALS seq. Cobbold, " The Sunfish (Orthagoriscus) as a Host/' ' Intell. Observer/ Sept., 1862. Idem, " Notes on the Calcareous Corpuscles of Tricuspidaria," ' Quart. Journ. Micr. Sci./ 1859. Idem, " Notes on Tricuspidaria and Pentastoma," ibid., 1859. Idem, " Note on Gyrodactylus elegans," ibid., 1862 ; see also Wedl. Idem, " On Distoma clavatum from the Sword-fish," 'Proc. Linn. Soc./ 1867 (Zool. Sect., p. 200). Idem, "Tape- worms in Trout/' letter to the ' Field/ July 26, 1873 ; see also F. Francis (below). Idem, " Remarks on the Entozoa and Ectozoa of Fish/' the 'Veterinarian/ Oct., 1867, p. 671. Idem, " On Agamonema crenilabri," in ' Science Gossip/ 1876 ; see W. W. Wilson. Idem, in ' Linn. Trans./ 1858. Idem, 'Note on Parasites from the Wolf-fish (Annarhicas) and Lump-sucker (Cyclopterus), collected by Mr Devis ' (1. c., Bibl. No. 57). Idem, " Descr. of the Scolex of a Tetrarhynchus," in a paper on 'Parasite Larvae/ f Intell. Observer/ 1863. Idem, "Synopsis of the Distomidas," ' Proc. Linn. Soc.' (Zool. Div.), 1860. Idem, " Remarks on Bothriocephalus latus, in relation to Dr Fock's supposition that the Bleak (Leuciscus alburnus) is con- cerned in its Production/' the 'Veterinarian/ July, 1878. Cornalia, E., ' Sopra una nuova specie di Crostacei Siphono- stomi (Gyropeltis doradis),' Milano, 1859. Ooughtrey, M., " On the absence of Tapeworm in the Salmon-trout of New Zealand," letter to the ' Otago Daily Times/ dated from the Otago Uni- versity, Dec. 6, 1875. Diesing, ' Vierzehn Arten von Bdelli- deen/ Wien, 1858; see also 'Revisions/ quoted in Bibl. No. 58. Donnadieu, A., "Etude sur les Ligules," in 'Archives Zool. Experiment./ 1876. Duchamp, (?., ' Recherches anat. et physiol. sur les Ligules,' Paris, 1876; see also Bertolus. FocJc, ' The Bleak as a source of the Broad Tapeworm.' See Cobbold. Francis, F., "Tapeworm in Fish" (with report by myself), in the 'Field/ June 28, 1873. Idem, in the 'Field' for July 12, 1873. Garsin, 'Histoire de 1'Acad. des Sci.,' Paris, 1730, p. 44. Goodsir, J., "On Gymnorynchus horridus, a new Cestoid Entozoon," ' Edin. New Phil. Journ./ p. 9, 1841. Hough-ton, W., ''On the occurrence of Gyrodactylus elegans in Shropshire/" Ann. Nat. Hist./ 1862. Huxley, "Note on Gyrodactylus," ' Proc. Roy. Inst./ April 20, 1852, and ' Edin. New Phil. Journ./ 1852, p. 172. Knocli, J., 'Entwick- elungsgeschichte d. Both, proboscideus,' 1862. Knox, J. F., " Note respecting the occurrence of a peculiar Microscopic Entozoon in the Textures of the Herring," ' Lancet/ 1838. PISCES 479 Kolliker, " Zwei neue Distomen," ' Ber. v. d. K. Zoot. Anstalt zu Wiirzburg/ 1849. Idem, ' Ueber Tristoma/ ibid., 1849. Leidy, J. y " Notice of a Tetrarhynchus (T. ienuicaudatus) in the Remova;" ' Proc. Acad. N. S. Philad./ Oct. 15, 1878; and in 'Ann. Nat. Hist./ Feb., 1879. Leydig, " Ueber Argulus/' 'Sieb. und Koll. Zeitsch./ 1850. Maddox, R. L., " Some Remarks on the Parasites found in the Nerves (and other parts) of the Common Haddock (Morrhua ceglefinus}," ' Trans, of the Roy. Micr. Soc./ 1867, p. 87. Menzies, ' Linn. Trans./ 1790, p. 187. Miescher, " On Filaria piscium," &c., in 'Excerpta Zoologica/ communicated by Dr Frances, in ' Ann. Nat. Hist./ l842.M'Intosh, W. G. y "Notes on the Food and Parasites of the Salmo solar of the Tay," 'Proc. Linn. Soc./ 1863; repr. in the ' Zoologist/ Feb., 1864. Muller, J.j "Note on a Parasitic Formation (Gregarina) in the Pike, with a statement from his 'Neurologie der Myxi- noiden/ that Diplostomum rachineum is to be found alive under the cerebral membranes of Petromyzonfluviatilis," from 'Miiller's Archiv/ in ' Micr. Journ. and Struct. Record/ p. 20, 1842. Nardo, in ' Heisinger's Zeitsch./ 1827, s. 68, and in ' Isis/ 1833, s. 523. Olsson, P., "Researches on the Flukes and Tapeworms chiefly of Marine Fishes," ' Bntozoa, iakttagna hos Skandanaviska Hafsfiskar/ Lund (aftr. ur ' Lunds Univ. Arsskrift/ torn, iii, iv), 1867-68. Owen, ' Zool. Soc. Trans./ 1835, p. 382. Pallas, ' Spicilegia Zoologica/ fasc. x, p. 18, 1774. Siebold, C. von, ' Band und Blasenwiirmer/ s. 41, Huxley's edit., p. 32. Idem, "On Diplozoon paradoxum," from ' Zeitsch. f. wiss. Zool.' (by Huxley), in < Ann. Nat. Hist./ 1851. Idem, " Ueber den Grenerationswechsel der Cestoden nebst einer Revision der Gattung Tetrarhynchus/' ' Zeitschr. f . wiss. Zool.,' 1850, s. 198. Idem, " Gyrodactylus, ein ammenartiges Wesen," ibid., 1849. Slack, H. J., " On Bucephalus polymorphous," in f Monthly Microsc. Journ./ April, J875, p. 141. Van Beneden (see Beneden). Verrill, A. E., " On the Parasitic Habits of the Crustacea," from ( American Naturalist/ in 'Scientific Opinion/ Aug. 4, 1869, p. 185. Idem, "New Flukes (Tristoma lave and T. cornutum) from the Mouth and Gills of Tetrapturus albidus," 'American Journ. of Science,' p. 40, 1875. Von Baer (see Baer). Von Sielold (see Siebold). Wagener, R. G., " Helminth. Bemerkungen," in e Sieb. und Koll. Zeitsch./ I8b7.Idem, " Enthelminthica," < Miiller's Arch./ 1851. Idem, "Ueber Eingeweidewurm (Amphiptyches) 480 PARASITES OF ANIMALS in Chimara monstrosa," ' Miill. Arch./ 1852. Idem, ' Beitrage zur Entw.-Gesch. der Eingeweidewurmer (Preisschrift)/ 1857. Wedl, " On Gyrodactylus " (see reference to my paper on ' G. elegans '), ' Quart. Journ. Micr. Sci./ 1862 ; trans, from his ' Anhang/ " Ueber die Gattung Gyrod./' to ' Anat. Beobach- tungen ueber Trematoden/ Wien, 1858. Idem, ' Haematozoa in Fishes/ &c. (1. c., Bibl. No. 58). Wigham, P., "Note on Holostotnum cuticola from Roach and Bream/' 'Ann. Nat. Hist./ p. 235, 1851. Wilson, W. W., "On a Parasitic Worm infesting a Marine Fish (Crenilabrus rupestris)," in f Science Gossip/ Jan., 1876. Yarrell, W., "Note on Tristoma coccineum," in his work on ' Brit. Fishes/ vol. ii, p. 353, 1836. PART IV (EVERTEBRATA) . Since a large proportion of all those helminths that require a change of hosts must needs pass into the bodies of insects, crustaceans, mollusks, or other evertebrated animals, it is evident that these lower creatures are almost as liable to be infested by parasites as the vertebrates themselves. As a rule, no doubt, the parasitic forms infesting individual evertebrated hosts are not numerous; nevertheless the water-snails form a noteworthy exception. Thus, some ten different species of parasite are found either in or upon the common Planorbis corneus ; whilst Lymnaus stagnalis, Paludina vivipara, and P. impura, each support at least a dozen species. Of course, the parasites are not sexually mature, since nearly all of them are Cercarics or larval trematodes. Snails, oysters, mussels, whelks, and other mollusks afford harbour and anchorage to a variety of parasites and messmates ; but, fortunately, few or it may be none of the strictly human parasites require to pass through these intermediate bearers. Distoma crassum is possibly an exception. Save the cuttle-fishes, not many evertebrated animals are infested by sexually-mature worms. One of the most notable exceptions is that of a nematoid infesting bees. This worm was known to John Hunter, who spoke of it as " the animal that breeds in the humble bee." In the year 1836, M. Leon Dufour first applied the term Sph&rularia to this remarkable worm, which he discovered in the abdominal cavities of two species of bee (Bombus terrestris and B. hor- torum). The worm was subsequently found by Von Siebold in EVERTEBRATA 481 two other species of bee (B. muscorum and B. sylvarum), but it remained for Sir John Lubbock to demonstrate that this parasite not only infests these insects, but also Bombus lucorum, B. lapidarius, B. pratorum, B. subterraneus, and Apathus vestalis. I possess specimens from Vespa vulgaris and F. rufa. Sir J. Lubbock and Mr. Cole have separately given full anatomical descriptions of the worm. According to Lubbock the so-called female is about an inch in length, of a whitish color, and " in thickness, being bluntly pointed at either extremity. Spharularia is everywhere covered by small warts or button-like projections, in all numbering about 800. The warts are transparent, each, according to Lubbock, project- ing from y^o" to T o 6 5o " above the general surface of the integu- ment. There is neither mouth, oesophagus, intestine, nor FIG. 85. Sphaemlar'ia bombi. Showing the supposed male in situ. After Lubbock. anus ; but in their place a large fatty mass or corpus adiposum. Sir J. Lubbock remarks that this peculiar organ "is homo- logous, not with the whole intestinal canal of nematodes, but only with the intestine ; and we find, in fact, that in Grordius the oesophagus is very short, and opens at once into the anterior end of the corpus adiposum ; so that to pass from this genus to Sph&rularia it would be necessary to shorten the oesophagus a little more, and then the wall of the corpus adiposum would be immediately attached to that of the body. So far, therefore, as concerns the corpus adiposum and the 31 482 PARASITES OF ANIMALS oesophagus, Spharularia agrees neither with Gordius nor Mennis, nor, indeed, with one more than the other ; since, if it agrees with Mcrmis albicans in the double series of large fat cells, it has no oesophagus, and in this respect more nearly resembles Glordius." The reproductive organs consist of a single ovary, uterus, and terminally situated vulva. These organs in the full-grown females contain ova in all stages of development up to the condition of advanced yolk segmenta- tion; but it does not appear that embryonic formation takes place whilst the eggs are still in utero. " The young animals are born soon after the eggs are laid. They are about 55" in length, and ^' in diameter at the broadest part. Before Sir J. Lubbock conducted his inquiries the so-called male appears to have been overlooked. The male, if male it be, is extremely minute ; that is to say, about 28,000 times smaller than the female. Notwithstanding this very circumstantial account based on Lubbock's determinations, Schneider has sought to show that the facts have been entirely misinterpreted. What Lubbock regards as the male worm is, in Schneider's opinion, a female, whilst the so-called female is nothing more than a gigantic prolapsed uterus which has become many thousand times larger than the body of the worm whence it proceeded. It must be allowed that Schneider's description and accompany- ing figures are very convincing. When revising the entozoa of the Hunterian Collection in 1866 I explained the specimens and dissections in accordance with Lubbock's views. In the following year Prof. Huxley in his College Lectures supported the view of Schneider, but in his recently published manual the opinions of the Berlin helminthologist are not so much as alluded to. Another point of special interest in connection with the parasites of insects concerns the development of Mermis albionix. At or near the time of the maturation of the ova, the parent worm, hitherto lodged within the body of some insect, buries itself in the soil. It commences its migration by boring its way out of the body of the host. Some difference of opinion exists as to the condition of the parent at the time of its wandering, for Von Siebold asserted that it quitted its parasitical mode of life " in order to become sexually mature away from the animal " infested ; whereas Van Beneden states that the embryos are always formed at the time of the wandering. From Von Siebold's experiments it would appear that in- EVERTEBRATA 483 completely developed Mermes can become mature whilst still in the soil ; but the normal condition requires the wandering to commence, as we have said, at or near the full time of embryonal development. The embryos are reproduced viviparously, and being set free, they pass a certain period of their existence in the soil. Here they grow rapidly, acquire sexual organs, and subsequently seek to " gratify their immigrative propensities," as Yon Siebold says, by selecting and penetrating the soft-bodied larvae of lepidopterous and other insects. This entrance they accomplish by means of a sharply-pointed dentule or boring stylet, which at the time of disuse is concealed within the head. Having once gained access to the host they remain within its body until the caterpillar has become transformed into the perfect butterfly, or until their own sexual maturity is completed. Yan Beneden thinks it probable that the males quit the host some time before the females, a view which, if correct, might alone account for the comparative scarcity of the males. According to Yon Siebold, sexual congress occurs before the entrance of the worm into the caterpillar. This observation agrees with the generally admitted fact that hitherto no male Mermes have actually been detected in the bodies of insects. The Gordii, like Mermes, become free in damp earth and penetrate the bodies of certain insects or their larvae. Some of them gain access to fishes. Like the free nematodes (Anguillulidtf) , many of the Gordii will survive complete desic- cation. The eggs of the mature worms are deposited in long agglutinated chains in water or damp situations. I must conclude. In the body of this work will be found many notices of insect parasites that are awaiting transference to some vertebrate. I need only allude to the r61e of the mosquito, to that of the louse of the dog, and especially to that of the little myriapod (Glomeris) which, like the common glow-worm (Lampyris), possesses phosphorescent properties. I mention this again partly in correction of an entomological error (at p. 296) which escaped me at the time of going to press. Leidy has described a mature nematode (Ascaris infecta) from Passalus cornutus, and numerous Filariae are known to infest insects (Blatta, Forficula, Pliosphuga, &c., &c.). From an earwig I obtained a filaria nearly five inches in length. We have seen that the larvae of Dracunculus, CucuUanus, as well as those of other important nematodes, dwell in bodies of entomostracous Crustacea, whilst those of Echinorhynchus attack 484 PABASITES OF ANIMALS the Gammari and their allies. The well-known Udonclla caligorum attaches itself to Crustacea that are themselves parasitic. As many of the so-called free nematodes live in the slime of animals, Villot is of opinion that no very distinct line of demarcation can fairly be drawn between the parasitic and free species. This work, however, having dealt only with genuine parasites, I have purposely omitted any detailed account of the so-called free nematoids. I mention this lest it should be supposed that I had shown a studied neglect of the more or less remarkable labours of Biitschli, Bastian, Eberth, Linstow, Marion, Villot, Glaus, De Man, Carter, and many others. BIBLIOGRAPHY (No. 60). Bastian, H. C., "Monograph on the Anguillulidae, or free Nematoids, marine, land, and fresh- water, with description of 100 new species/' ' Linnean Trans/ for 1865, vol. xxv, p. 73. Idem (see Bibliog. No. 2). Linn, " Free Nematoids," being an article in the { Popular Science Review' for 1868, vol. vii, p. 163. Brady, 0. S., ' Monograph of the free and semi parasitic Copepoda/ London, 1878. Butschli, 0., " Untersuchungen ueber freilebende Nematoden und die Gattung Chaetonotus," ( Sieb. und Koll. Zeitschrift/ 1876. Carter, H. J., " On a Bisexual Nematoid Worm which infests the common House-fly (Musca domestica)," ' Ann. Nat. Hist./ 1861, and in the 'Bombay Med. and Phys. Soc. Trans./ new series, 1860. Claparede (see Panceri). Glaus, C., ' Beo- bachtungen ueber d. Organis. und Fortpflanz. v. Leptodera appendiculata,' 1869. Cobbold, " Note on Insect Parasites/' in ' Rep. of Entomological Club/ in the ' Midland Naturalist/ March, 1878, p. 80. Cole, W., " Remarks on a Parasite of Humble Bees/' in ' Journal of the Quekett Microscopical Club/ 1875. Dufour, L., " Sphserularia," < Ann. des Sci. Nat./ 1836. Dujardin, " On Mermis," ' Ann. des Sci. Nat./ 2e ser., torn. 18, p. 129. Eberth (see Bibliog. No. 2). Garner, R., " Note on a Distoma," in his paper ' On the Lamellibranchiate -Conchifera/ ' Trans. Zool. Soc./ 1841. Ghaleb, 0., "Observa- tions and Experiments on the Migrations of Filaria rhyti- pleurites, a Parasite of Cockroaches and Rats," ' Comptes Rendus/ July 8, 1878, and ' Ann. Nat. Hist./ Aug., 1878. Idem, " Note sur 1'anat. et les migrations de deux Nematoides parasites, le Poecilogaster blatticola et Fil. rhytipl.," Paris, 1876 (quoted by 0. von Linstow). Giard, M. A., " On the parasitic Isopoda of the genus Entoniscus (infesting Crustacea)," from 'Comptes Rendus/ Aug., 1878, in 'Ann. Nat. Hist,/ Otc., EVEKTEBRATA 485 1878. Idem, " On the Orthonectida, parasitic on Echinoder- mata and Turbellaria (Rhopalura)," 'Ann. Nat. Hist./ Feb., 1878. Grube, A., " On Cyclops as a new Cestoid-bearing Host," from ' Zoologisch. Anzeiger/ Bd. i, s. 74, in ' Journ. Royal Microsc. Soc./ Nov., 1878, p. 254. Hunter, J., " Filaria of the Bee," in ( Catal. (by Owen) of the contents of the Mus. Royal Coll. Surg./ part iv, fasc. i, p. 37, 1830. Kynston, " Worms attached to a Grasshopper," ' Proc. Ashm. Soc./ in ' Corbyn's India Review/ and in ' Journ. of Foreign Sci./ 1837, p. 172. Lima, J. F. da S., " Remarks on the Filaria medi- nensis or Guinea-worm ; on the occurrence of this parasite in the Province of Bahia; and on its entrance into the human body by drinking water;" trans, from the Portuguese by Dr J. L. Paterson, and pub. in the ( Veterinarian ' for Feb., 1879 et seq. Linstow, " Helminthologische Beobachtungen," in 'Archiv fiir Naturgeschichte/ 1876. LubbocJc, Sir /., "On Spharularia bombi," 'Nat. Hist. Rev./ 1861. Idem, "Notes," &c., ibid., 1864, p. 265. Mason, J. W., " Note on the Geo- graphical Distribution of the Temnocephala chilensis (parasitic upon a freshwater crayfish, Paranephrops setosus, in New Zealand)," ' Annals Nat. Hist./ 1875, p. 336. Marion, A. F., f Revision des Nematodes (&c.)/ Marseilles. Maund, B., " A description of Filaria forficula," ' Rep. Proc. Linn. Soc.,' in 'Zool. Journ./ 1832-34, p. 263. Meissner (see Thomson). Owen, E. (see Hunter). Pagenstecher (see Bibl. No. 58). Panceri, P. (e di E. D. Claparede), "Nota sopra une alciopide parassito dell Cydippe densa," e Mem. della Soc. Ital. di Sci. Nat./ 1867. Sars, "Intestinal Worm in an Acaleph.," from 'Wiegmann's Archiv/ in 'Ann. Nat. Hist./ 1845. Siebold, G. J. von, in 'Wiegmann's Arch.,' 1835. Idem, in 'Ray Soc. Rep/ (by Busk), 1847. Idem, "Worms," &c., ibid., p. 503, 1847. Idem, " Report on Helminthology, and on the Nemer- tinae" (trans, by W. B. Macdonald, in ' Ray Soc. Rep. on Zool./ 1842, p. 280), Edinburgh, 1845. Idem (see Thomson). Thom- son, A. (for review of the writings of Meissner, Von Siebold, and others, respecting the development of Mermis, Gordius, &c., see the classical and elaborate art. " Ovum "), in ' Supp. to Todd's Cyclop./ 1859. Vogt, G., " On some Inhabitants (Cercarise) of the Fresh-water Mussels," from 'Ann. des Sci. Nat./ in 'Ann. Nat. Hist./ 1850. Whitman, C. 0., "The Embryology of Clepsine (with valuable Bibliography)," ' Quart. Journ. Micr. Sci./ July, 1878. 486 PARASITES OF ANIMALS APPENDIX. The memoirs announced by Dr T. R. Lewis in the January issue of the ' Microscopical Journal/ and referred to at the close of my account of Filaria Bancrofti, having appeared, I fulfil the promise previously made (p. 202). In the few lines at my disposal I may observe that the beautiful brochure (quoted below) supplies fuller details of the results already announced by Lewis in the ( Proceedings of the Asiatic Society of Bengal/ In respect of the nematoid haematozoa, the memoir is chiefly important as confirming Hanson's observa- tions regarding the changes undergone by the Filariae that have been transferred to the stomach of the mosquito, and especially also, as advancing some novel facts in reference to the occurrence of bird's blood-corpuscles, associated with embryonic nematoids, in the same viscus of the insect. The worms are regarded by Lewis as transferred avian haematozoa, a view which gains strength by their comparison with the similar larvae which he had detected in the blood of Indian crows (Corvus splendent). In Egypt, as Sonsino had himself informed me by letter, similar haematozoa are to be found in crows, and avian filariae of this kind were long previously described, as Lewis and Sonsino point out, by Borell, Herbert, Schmidt, and Virchow. Facts of this order undoubtedly complicate matters, and suggest that extreme measure of caution in drawing conclusions, which Lewis himself everywhere displays. Respecting the final changes undergone by the mosquito- filariae before their re-entrance into the human body, Lewis does not appear to have gone further than Dr Manson. By rupturing the body of the most advanced larvae, Lewis readily recognised the oesophagus and intestine, but he remarks, significantly, " I have not been able to distinguish any other differentiated viscus in any of the specimens, and certainly, nothing suggestive of differentiation of sex " (p. 83) . In an earlier part of the me- moir Dr Lewis takes objection to my view that the urinary nematoids found by me in a case of Bilharzia are genetically related to Filaria sanguinis hominis. His distinguished coad- jutor, Dr D. Cunningham, also denies the possibility of such relationship. No doubt, if the urinary maternal worm was really oviparous my view is untenable ; but the proved presence of imperfectly formed ovarian ova, in which no trace of embryonic formation was discernible, has forced upon me the conviction that prolapsus and rupture of the uterine tubes of the parent worm had occurred, and that their rupture had occasioned the escape APPENDIX. 487 of ova in various stages of growth. As free embryos were also detected, the adult worm was probably viviparous. There is an error in the representation of the oval-shaped ovum given in the figure (p. 183). I retain drawings of eighteen perfect nematoid ova from the Bilharzia case, and not one of these shows any double contour of the chorional envelope. In the case of the imperfect ova, the double contour is obviously due to the close apposition of the yelk-membrane to the shell- membrane, there being no true shell. As regards " a correc- tion " which Lewis makes in respect of the question of priority of description of the mature Filaria sanguinis hominis I can only find space to state frankly, that Lewis is perfectly correct. The error was quite unintentional on my part. The adult worm was first discovered by Bancroft, and upon the strength of his admittedly scanty record I named the worm Filaria Bancrofti. In the matter of supplying a proper diagnosis and an anatomical description I was completely anticipated by Lewis. No doubt, Dr Bancroft could have furnished a fuller description of the parasite, had he desired to do so, but here is what he says in the letter addressed to me from Melbourne on the 20th of April, 1877 : " I thought it better to send you this account of filarise than to publish it direct, as you so kindly set me on the track of the investigation." Here I feel constrained to remark that few, if any, of my many correspondents in helminthology, have displayed more engaging candour. Whilst actually writing this Appendix (April 15th, 1879) I have received a new record of filarious cases from Dr Bancroft, who also sends me some mosquitoes captured by a victimised patient whose blood swarmed with filariee. In one of the captured insects Bancroft himself detected forty-five filarise. The cases have been for- warded to the ' Lancet ' for publication. Lastly, in reference to the closing paragraph of Bancroft's previous letter to me (pub. in the 'Lancet,' Feb. 1st), I have received the following interesting commentary at the hands of Dr Silva Araujo, whose letter is dated from Bahia, March 3rd, 1879 : " Je dois vous communiquer que ce fait vient confirmer 1'idee qui existe chez nous, ou le peuple croit et affirme que qnand une per- sonne qui souffrait auparavant d'erysipele a un abces cela la preserve de nouveaux acces. La raison ne sera-t-elle pas que dans ce cas, avec Touverture de 1'abces, le ver sort ? Je le crois. Ces faits viennent demontrer que la cause de la maladie est le ver. Cependant nous avons ici a Bahia plusieurs con- 488 PARASITES OF ANIMALS freres qui ne le croient point ! Et a Rio- de- Janeiro aussi il y en a, peut-tre davantage (!)." I will only add that Dr Araujo deceives himself if he imagines that the full etiological sig- nificance of parasites in relation to disease will receive general professional recognition for many years to come. SUPPLEMENT TO BIBLIOGRAPHY No. 23, p. 202 (with emenda- tions). Araujo, ( Memoria sobre a Filariose ou a molestia pro- dusida por uma nova especie de parasita cutaneo/ Bahia, 1875. Idem, " Da filariose," ' Globo/ Jornal do Rio de Janeiro, 1876, e 'Re vista Medica do Rio de Janeiro/ 1876, anno 3o, No. 2, 15 de Julho, p. 107. Idem, " Caso de chyluria, ele- phancia do escr6to, escr6to lymphatico, craw-craw e erysipela em um mesmo individuo ; descobrimento da Wuchereria filaria na lympha do escr6to. Tratamento pela electricidade com excellentes resultados," ' Gaz. Med. da Bahia/ 2a serie, vol. 2o, No. 11, Nov. de 1876. Idem, "A Filaria Wuchereri no sangue," 'Gaz. Med. da Bahia/ Mar. de 1878, p. 106, e seguintes. - Idem, " A muri9oca e as filarias Wuchereri," ' Gaz. Med. da Bahia/ Setembro de 1878. Idem, "La Fil. immitis," &c., Transl. of Mem. (I. c., Bibl., No. 45) in ' Lyon Medical/ Nov., 1878, p. 319 et 363. Bancroft, "Instance of a European having taken leprosy in Queensland/' in a letter to myself ; see " Case from Bancroft/' quoted at p. 203. Chassaniol, A. (et F. Ouyot), " Hematurie graisseuse ou chyleuse," in their " Notes de Geo- graphie Med. recueillies a Taiti," in Archives de Med. Navale/ Jan., 1878, p. 65. Colloid, " Worms in the Heart of Dogs/' letter in the ' Lancet/ April 5, 1879, p. 498. Coles, "On Lymph- scrotum/' 'Brit. Med. Journ./ March 9, 1878. Fayrer, Sir /., " Lecture on Elephantiasis Arabum," in the ' Lancet/ March 29, 1879, p. 433. Idem, 'Report of Pathol. Soc./ 'Lancet/ Feb. 22, 1879, p. 267. Idem, ' Rep. of Epidemiological Soc./ ibid., p. 269. Idem, 'Letter on Filaria/ see Hoysted. Okaleb, 0. (with P. Pouquier), " On Filaria hamatica," from ' Comptes Rendus/ Feb. 5, 1877, in 'Annals Nat. Hist./ April, 1877. Hoysted, J., " Notes of a Case of Filaria sanguinis in a Dog /' see Bibliog. No. 49, p. 311. Lewis, T. R., 'The Microscopic Organisms found in the Blood of Man and Animals, and their relation to Disease/ Calcutta, 1879. Idem, " The Hsematozoa of Man (excerpt of the above)," 'Quart. Journ. of Microsc. Sci./ April, p. 245 (both from ' 14th Ann. Rep. of the San. Commis- sioner with the Govt. of India'). Makuna, ' Letter respecting Fil. sang. horn, in Chyluria ' (1. c., Bibliog. No. 23). INDEX. PAGE Acanthia lectularia, or the common bed bug * j, . 273 Acanthocephala in birds . . . . . . 446 include but one family . . . .5 in the Hunterian Museum . . . 413 Acanthotceniadcp., a family of tapeworms . . . .4 Acaridce, a family of Arachnida . . > , . .5 Acephalocysts in cattle, Hunterian specimens of . . . . 140 Agricultural societies, their indifference to helminthology . . . 412 Aguti, Spiroptera mediospiralis from the .... 403 Alligator, entozoa from an . . . . . . 455 Amphistoma and Polystoma in the frog . . . 452 hominis, notice of Lewis's and McConnell's . . .36 subclavatum, ciliated embryo of . . .49 Amphistomes infesting deer ...... 332 elephants ..... 395 the horse ..... 357 Amphistomidce, a family of flukes . . . . .4 Anaemia, tropical, due to Anchylostomata .... 203 Anchylostomum-helminthiasis, Wucherer's account of the . .213 Anchylostomum (DocJimius) duodenale, description of . . 212 Aneurism of the horse, Bellinger's account of . . . 368 Anguillula (Leptodera) stercoralis, description of ... 234 Anguillulida, a family of round worms . . . .5 Annelid parasites, ectoparasitic character of the . . . .6 Anoplocephala perfoliata as a synonym .... 401 Ant-eaters, internal parasites of . . . . 321 Antelopes and deer, Pentastomes found in . . .350 Anthomyia canalicularis as a human parasite .... 271 Arachnid parasites, various families of . . . .5 Argulidce, a family of parasitic crustaceans . . . .6 Arhynchotcenia critica of the hyrax ..... 403 Arhynchotceniada, considered as a group . . . .4 Armadillo, parasites found in the . . . . .321 Ascaridce, a family of round worms . . . . .4 Ascarides infesting cetaceans ..... 426 (Oxyurides) in relation to cleanliness .... 232 Ascaris alata, Bellingham's so-called ..... 237 Cornelyi from the vulturine pintado .... 447 halicoris from the Indian dugong . 429 490 INDEX PAGE Ascaris infecta from Passalus cornutus .... 483 lumbricoides as a human parasite .... 243 Davaine's experiments with . . . 2 1 1 development of the .... 244 Heller's " find " respecting the young of . . 244 remarkable cases caused by the . . . 248 maculosa causing avian epizoSty .... 441 Unterberger's experiments with .' . . 245 megalocephala and A. lumbricoides not identical . . . 243 experiments with the eggs of . . 246 of solipeds . . . . .378 mystax considered as a human parasite .... 237 Leuckart's experiments with .... 244 researches of Nelson respecting . . . 240 nigrovenosa, parthogenesis of . . . . .432 . suilla considered as a synonym .... 243. rf of the hog, a synonym ..... 405 tentaculata of opossums ..... 433 tetraptera, development of the embryos of ... 245 vesicularis from the ring-necked pheasant . . . 4 12 Aspidocephalus scoleciformis of opossums .... 433 Aspidocotylus mutdbilis, a parasite of fish .... 360 Ass, frequency of aneurism in the ..... 367 liver-fluke frequent in the ..... 356 strongyles from the stomach of the .... 383 Australian entozoa, Mr Krefft's brochure on . . .431 hedgehog, tapeworm from the .... 433 Avian htcmatozoa, observations by Lewis on . . . 486 ., parasites in the British Museum .... 448 ,, in the Hunterian Museum .... 448 Bacteria, the best known forms of . . . . 277 BacteridfB, as a family of protozoa . . . . .7 Balantidium (Parameciuni) coli of man .... 282 semiparasitic character of . . . .7 Bal from ..... 425 fluke from . . . . .421 Bats, entozoa and ectozoa infesting ..... 294 Bear, Cysticerci in the heart of a . . . .140 Beef, cyst -infected, quantity destroyed in India . . . .76 in India, prevalence of " measled " . . .61 tapeworm, description of the so-called . . . .56 Bee, parasite of the, known to John Hunter .... 480 Beetles (Passalus) infested by nematodes .... 483 Beluga leucas, worm from the ear of . . . . . 427 Bilharzia h&matobia, history and development of the . . .38 Birds, frequency of entozoa in ..... 434 Spiroptera helicina in the feet of .... 440 INDEX . 491 PAGE Birds, the gape disease in ...... 443 Blackbirds, tapeworms destructive to young .... 440 Blackcap, flukes reared by Zeller in the .... 436 Blackfish or tursio, cestode from the ..... 422 Bladderworms and measles in cattle . . . . .62 Blaptida as parasitic insects . . . . .7 Slaps mortisaga as a human parasite ..... 270 Bleak, the (Leuciscus), a possible source of tapeworm . . . 301 the, in relation to BotJiriocephalus latus . . . 470 Bonito, parasites from the ...... 458 Bopyridce, a family of parasitic crustaceans . . . .6 Bothrocephali of water-birds obtained from fish .... 468 researches of Bertolus and Duchamp on . .110 Bothriocephalus cordatus, brief description of t ; . . Ill cristatus, brief description of . % . Ill in Holland, Dr. Fock's remarks on . . 109 latus, distribution and characters of f . .106 source and proscolices of . . . . 107 proloscideus of the salmon . . . . 468 tropicus, note on the so-called . . . .96 Bot infesting the stomach of the rhinoceros .... 401 Bottle-head (Hyperoodon), flukes from the . . . . 421 Brain, Cysticerci occurring in the human . . . .92 Bronchi of whales, worms in the ..... 425 Bucephalus probably a larval state of Gasterostorna . . . 462 regarded as a germ -sac ..... 453 Bug, the common, as a human parasite .... 273 Cachalot, cestode from the high-finned .... 422 Calceostoma, hooks of the suckers of . . . . . 464 Caligidce, a family of crustaceans . . . . .6 Campula oblonga regarded as a synonym ; . . . 419 Capercaillie, entozoa of the ...... 440 Trichosoma and Ligula from a . . . 447 Carnivora, internal parasites of the ..... 297 CatapJiractus infested by Aspidocotylus .... 360 Cat, Australian, Bothriocephalus from .... 309 flukes and tapeworms infesting the .... 308 Cattle diseased by parasites, natural cure of . . .83 measles and bladderworms in . . . . .61 of the Upper Punjab infested by cysts, percentage of . .75 plague bodies, nature of the so-called .... 280 species of lice infesting ..... 352 tapeworms found in . . . . . . 332 Cercaria diplocotylea of water-snails . . . . . . 452 of the common fluke ..... 325 Cercarice and Redia, Pagenstecher's remarks on ... 452 Cercomonas hominis in cholera dejections .... 282 Cestoda, families of the order . .4 Cestode (larval) in Delphinus delphis ..... 422 492 INDEX PAOB Cetacea, external parasites of ..... 428 parasites of . . . . .416 in Hunterian collection . . . 427 worms in the lungs of ... 423 in the cranial sinuses of . . . .425 Chacma, strongyles found in the . . . . .291 Charbon, an anthracoid disease associated with bacterids . . . 278 Cheetah, tapeworm found in the . . . 300 Cheiracanthidee, a family of round worms , . .4 Cheiracanthus robustu* in Indian dogs . . 305 mistaken for Echinorhynchus . . . 257 Cheiroptera or bats, parasites of . . . 293 Chigoe or jigger as a human parasite ..... 274 Chinese missionary, flukes in the family of a . . .21 Cirrhipeds, parasitic, upon whales ..... 428 Civets, parasites found in . . . . . 299 Classification of Schneider referred to . . . . .4 Clepsinidee, a family of suctorial annelids . . .5 Coati, intestinal worms of the ... 1~* . 298 Cochin-China diarrhoaa due to Leptodera .... 235 Cockchafers harbor young Echinorhynchi . . . 413 Cockroaches (Blatia) infested by nematodes . " . . .483 Codfish, frequency of filariae in the . . . . 472 Caenuri from rabbits in Guy's Museum and at Oxford . . . 140 researches of Rose and Numan respecting . . . 334 Ceenurus cuniculi, specimen of, from Ayrshire .... 140 serialis of the hyrax ..... 403 Conocephalus typicus from a dolphin ..... 426 Conopida, the larvae of, as parasitic insects . . . .6 Conorhinus nigrovarious or pampas benchucha .... 273 Cotylogaster cochleariforme not an equine parasite . . . 360 Crane, entozoa from a ...... 447 Crossophorus collaris of the hyrax ..... 403 Crocodile, worm from beneath the skin of a . . . 456 Crows, haematozoa in Indian ..... 486 Crustacea, parasitic, upon whales ..... 428 the, as alleged human parasites .... 269 Crustacean parasites, families of . . . .6 Crustaceans, entozoa infesting ..... 480 Cucullanidce, a family of round worms . . . .4 development of the ..... 474 Culex, various species of, attacking man .... 273 Curlew, entozoa from the ...... 447 Cuterebra noxiali*, or Macaco worm . . . . .271 Cuttle-fishes, tapeworm larvae found in .... 468 Cyamida included with Pycnogonidae . . . . .5 Cyamus balcenarum or whale-louse ..... 428 Cyclobdella lumbricoides, the, of Brazil .... 259 Cyclops considered as an intermediate host : 223 Cymothoidce, a family of parasitic crustaceans . . . .6 INDEX 493 PAGE " Cyst ' -affected meat in the Punjab, quantity of . . .76 Cystic disease in cattle, Dr J. Fleming on . . .76 entozoa are larval tapeworms . . . . .4 Cysticerci, common situation of, in ration meat . . . .78 destruction of, by calcareous degeneration . . .83 detected in the living animal . . . .78 from sheep, Dr Maddox on . . . . .98 from the nasal sinuses of a porpoise . . . .421 from the skin of Physeter ..... 421 in the heart of a bear ..... 140 in the human body, seat of . . . .^91 in the psoas muscles, Dr Joseph Fleming on , , , .75 in meat, Pellizzari's and Tommasi's researches on . .62 investigations of Lewis respecting . . * .66 monstrous varieties of * . . 105 of the sheep alleged to contain eggs . ... . . 98 prophylactic measures respecting . . . .83 researches by Perroncito on . . . .67 said to be capable of swimming . . . .97 temperature necessary to destroy . . . .69 voluntarily swallowed by Italian gentlemen . . .71 Cysticercus bovis found in the liver and lungs . . . .59 human feeding experiments by Oliver with . . 72 del/phini, nature of the so-called .... 422 found in the dog ..... 302 from the Red River hog ..... 405 in the brain, cases of . . . .92 of the sheep, discovery of the . . . .97 report by Dr Neill respecting . . . .80 (telce) celluloses, or pork measle .... 89 tenuicollis found in man ..... 101 , the self -feeding experiment by Moller with . . 72 Cysts at the root of the tongue, diagnostic value of . .80 of the liver containing psorospermiae .... 282 Dactylogyrus, allusion to the eggs of . . . . .42 Dasse (Hyrax), parasites of the . . . . 403 Dasyprocta aguti, stomach excrescences in . . . . 403 Deaths from worms, Registrar General's returns of ... 285 Deer, abundance of amphistomes in . . . . 332 filariae found in various kinds of .... 350 Delphinus Forsteri, tapeworm found in . ... . 422 phoccena, cestode (Diphyllobothrium) from . . . 422 rostratus, tapeworm from ..... 422 tacuschi, flukes found by Natterer in . . . . 417 Demodex folliculorum of man and dog .... 266 Dermatophagoides Scheremetewsky, the so-called . . . 266 Dibothridce and Bothriocephalidce as synonyms . . . .4 Dibothrium Mans, supposed monstrous state of . . . . 105 Dichelestida, a family of crustacean parasites . . . .6 494 INDEX PAGE Dicotyles (Peccary), parasites of the genus .... 404 Dicrocoelium Buskii as a synonym . . . . .20 Didelphys philander, acantliocephalous worm of ... 434 Diphyllobothridce, a family of tapeworms . . . .4 Diphyllobothrium stemmacephalum from a porpoise . . . 422 Diplodiscus subclavatus, water- vessels of the larvae of . .51 Diplozoon in the Diporpa condition ..... 464 Diseased meat from " rot " . * *" . . . .331 Distoma Andersoni from Platanista ..... 420 campula of the porpoise ' . ' ^ . . . 418 clavatum, particulars respecting .... 458 conjunctum as a human parasite . . . .30 crassum or Busk's fluke . . . . .20 cygnoides, ciliated embryo of . . . .49 gigas of Nardo, description of the . . . . 460 hepaticum a synonym of Fasciola . . . .15 heterophyes, description of the . . . .34 ,, lancea infesting dolphins ..... 416 lanceolatum as a human parasite . . . .17 ciliated embryo of . . .49 description of the . . . .18 leptosomum and D. brachysomum, source of . . 438 macrostomum, development of .... 435 megastoma, ciliated embryo of . . . .49 militare, development of . . . . 436 neuronaii Munroli, the so-called . . . .52 ,, ophthalmobium, notice of the so-called . . . .36 sinense, or the Chinese fluke . . . . .29 species of, in Delphinus Forsteri . . . .421 Distomata confounded with proglottides . . . .16 Distomidce, a family of flukes . . . . .4 Distomum spatulatum as a synonym . . . . .28 Dochmius duodenalis, discovery of, by Dubini . . . .211 Sangeri from the elephant ..... 399 Dogs, destruction of dogs by heart- worms .... 304 Dog, ectozoa and follicle mites of the ..... 307 internal parasites of the ..... 300 Dolphin, remarkable worm from the stomach of a . . . 426 Dolphins, fluke parasites of . . . . . .416 Dorado, Fasciola fusca from the ..... 459 Dracunculus, description of the embryos of . . . 221 Fedschenko's discovery respecting .... 223 medinensis, description of the .... 217 Duck, worms from a dusky ...... 447 Dugong, parasites of the . . . . * . .429 Ear of the porpoise, worms found in the .... 427 Earth-wolf, remarkable parasite from the . . . . 299 Earth-worms as intermediate bearers ..... 346 Earwig, Filarice found in the . . 433 INDEX 495 PAGE Echidna, tapeworm from the . . . . . 433 Echinococci described by Leuckart and Naunyn . . . .117 Echinococcus brood-capsules known to Wilson and Busk . . . 117 Echinococcus hominis, synonyms of . . . . 112 multilocularis found in a calf .... 116 EehinorJtynchidce abound in fishes and reptiles . . . .5 Echinorhynchi found by John Hunter ..... 427 infesting monkeys ..... 292 in trout, frequency of . . . . . 475 of water newts . . . . . 455 EchinorhyncTius angustatus and E. hominis .... 413 gigas as a human parasite .... 256 of the hog . 412 hominis, Lambl's so-called '. . . . 256 in man, Welch's supposed case of ... . 256 Leuckart on the development of ... 476 microcephalus from an opossum .... 434 Muriel from a whale ..... 427 pellucidus and E. brevicollis . . . . 428 porrigens from whales .... 427 spirula of monkeys . . . . . 413 transversus in birds ..... 446 EcTiinostoma Mspidum from a sturgeon .... 462 Ectozoa of swine . . 414 of the elephant . . 399 of whales . . ' . ' 428 Edentata, parasites of the . ' . . 321 Eel, EcUnorhynchi in the . . 475 Eggs, entozoa found in the interior of . . 440 Elephants destroyed by " rot " in Burmah .... 394 earth-eating habits of worm-infected . . . 395 ectozoa of ... 399 in England destroyed by worms . 399 parasites infesting ..... 393 parasitic diseases of . . . . 397 Entozoa do not result from diseased states . . . .1 of game birds, list of . . . . 440 their relation to the helmintha . . . .8 Epidemics of rot disease . . . . . . 327 Epizoa, haustellated crustacean parasites . .6 Epizob'ty amongst elephants from flukes . . . 394 amongst pigeons . . . 441 in birds, very destructive to life .... 435 in cats, Dr Romano's account of . . . 308 in swine from EchinorhyncTius .... 413 in tenches from Ligulcs ..... 469 in the hog from Stephanurus .... 411 ,. in the Mauritius from worms .... 382 in the pig from Strongyli ..... 412 in young blackbirds from tapeworms .... 440 496 INDEX PAGE Eustrongyli within the skull of water-turkeys .... 446 Eustrongylus gigas, description of ... . 207 in dogs and wolves .... 305 source of the . 208 wild animals infested by . . . .207 papillosus from a crane ... . 447 Eye-worms in cattle . - 349 Eye of the fowl infested by filarim . . 440 Fasciola clavata, description of the so-called . 459 hepatic a as a human parasite . . .14 as a " zoological " individual .... 325 ciliated embryo of . . . . .48 Jacksoni infesting elephants .... 397 Fauna, parasites form a peculiar Ferret, ectozoon infesting the ears of the . . 307 Filaria acuta in the limbs of birds ..... 447 Banerofti, history of the discovery of . . 180 gracili* infesting monkeys . . . .291 homini* oris, description of the . 206 horrida from the American ostrich .... 447 immitis in the heart of dogs . . . . .304 inflexicaudata from Salanoptera .... 425 of the porpoise .... 425 labial is, description of the ..... 206 lacrymali* as a synonym ... . 206 lentis, notice of the so-called ..... 205 loa, notice of the so-called ..... 205 macropodis gigantei in the Hunterian Museum . . . 433 Mansoni in the eye of a fowl ..... 441 medinensis considered as a synonym .... 217 microstoma and F . megastoma, temperature necessary to kill . 70 oculi considered as a synonym ..... 383 papillosa hcematica canis domestici .... 184 in the horse . . . . .383 Salisburyii considered as a synonym .... 187 sanguinis, Bancroft's account of the *. 189 . equi, the so-called ..... 384 hominis, correction respecting .... 487 discovery by Lewis of ... 183 spelaa from a wallaby ..... 433 (Strongylus) bronchialis, description of . . . . 207 terebra in the black-tailed deer . . . .349 trachealis, remarks on the 207 Websteri proposed as a synonym .... 433 Filarite as a cause of abscess and erysipelas .... 487 discovery of microscopic, by Wucherer . . . .183 haematozoal, of Grube and Delafond .... 303 in human blood, Sonsino's verification of ... 185 of the mosquito, Hanson's description of ... 194 INDEX 497 PAGE Filaridce, a family of round worms . . . . .6 Fishes largely infested by EcUnorhyncM .... 477 of Brazil, amphistomes in the ..... 463 parasites of ...... 457 Flea, the common, of man ...... 274 Fluke, description of the common liver . . . .15 description of the large human . . . . .24 origin and meaning of the term . . . ",...' 4 Flukes abundant in the great kangaroo . .' . .431 causing " rot " in elephants . . . . . 394 found in fishes . . r . . . 457 found in ruminating animals ..... 323 Pagenstecher's researches on . . . . 452 their destiny favoured by mimetism .... 436 Fox, fluke of the American red ..... 299 source of tapeworms infesting the .... 300 Fowl, entozoa infesting the common . . . . . . . 440 Free nematoids, Villot's opinion respecting the . - . .. ;. . 483 Frog, Ascaris nigrovenosa of the . . . luafe-t . . 452 Oaleodes araneoides or canal tick ..... 267 Gallinula chloropus, worms in the limbs of . . . 447 Gamasida, a family of Arachnida . . . . .5 Game birds, list of entozoa infesting ..... 440 Gammarus pulex as an intermediate host . . . 476 Gape disease, methods of preventing and treating the . . . 445 " Gapes " in birds due to Sclerostoma ..... 443 Gasterostoma gracilescens, probable larval condition of . .52 peculiarities of the genus .... 462 Gastrodiscus Sonsinonis of the horse ..... 359 Gastrophilus rhinocerontis, a bot-fly ..... 401 Gid hydatid found in various animals ..... 333 in the hog noticed by Florman ..... 405 Giraffe, large fluke found in the ..... 323 Glossina morsitans as a human parasite .... 273 Glow-worm (Lampyris), correction respecting the . . . 483 Gluttons, internal parasites of the ..... 298 GnatJiostoma hispidum of the hog ..... 412 Goat, the beef-measle discovered by Zenker in a . . . .83 Gongylonema pulchrutn of the hog ..... 412 Goose, worms from the ashy-headed ..... 447 from the Sandwich Islands .... 447 GordiidcB, a family of round worms . . . . .5 Gordius survives desiccation ..... 483 Grebe, worms found in the legs of the lesser .... 447 Gregarinidce, as a family of protozoa . . . . .7 Grouse-disease, parasites producing the .... 433 entozoa of the red . . . . . . 440 GuUeria proposed as a generic title . ... 7 Guillemot, entozoa from the ..... 447 32 498 INDEX PAGE Gulls, entozoa found in . . . . . 447 Guinea- worm, development of the ..... 223 geographical distribution of the .... 218 Gymnorhynchus horridus as a synonym . . . .471 Gyncecophorus hcematobius considered as a synonym . . .39 Gyrodactylida, a family of flukes . . . . .4 Gyrodactylus, conclusions of Wedl respecting .... 465 elegant, development of . v . . . 466 Haddock, frequency of ftlarise in the . . . - . . 472 Halmaturus Derbyensis, nematodes of ... . . 434 Hams, Cysticerci in Westphalian . . . . . .405 Hares and rabbits, entozoa of . . . . .318 Hawk, entozoa from the sparrow ..... 447 If&matomyzus (Idocoloris) elephantis ..... 399 Il&matopinus of the hog . . . . . .414 Ilamatopota pluviali* or the clegg ..... 273 Haeraatozoa in dogs, discovery by Grube and Delafond of . . . 184 in Egyptian and Indian crows .... 486 of the dog . . . . . . 303 Hseraaturia caused by Silharzia hamatobia . . . .54 Hcementeria, American leeches of the genus .... 259 Hcemopis sanguisorba attacking French soldiers .... 258 Heart of whales, worms in the ..... 425 Hedgehog, parasites of the common ..... 295 tapeworm from the so-called Australian . . . 433 Helmintha, the term in relation to " worms " . . .8 Helminthology, practical results from the study of . .3 Helophilus, larva of, found in man . . . . .273 larvae found in the horse ..... :i^7 Herring, frequency of filaria in the ..... 472 Hesslingia proposed as a generic title . . . . .7 Heterocheilus tunicatus from Natterer's manatee . . . 429 Heteroura androphora, sexual peculiarities of . . . 445 Hexathyridium pinguicola and 11. venarum . . . .36 Hippoboscidce contain parasitic insects . . . .6 Hippopotamus, parasites of the ..... 402 Ilistiocephalus, a genus of nematodes ..... 433 Hog, absence of tapeworms in the ..... 404 cholera, supposed connection with Stephanurus . . . 410 skin affection from parasites in the wild .... 414 Hog's flesh, supposed injuriousness of . . . . 404 intestines perforated by parasites . . . .413 Hogs, Stephanurus discovered in a Chinese race of ... 408 Horse, aneurism in the, from parasites .... 368 a thousand amphistomes found in the .... 358 bladderworms found in the . . . . 366 bots or larval gadflies of the . . . . . 385 earth-eating habits of, in relation to worms . . . 357 ectozoa liable to attack the . 388 INDEX 499 PAGE Horse, epizooty from strongyles in the .... 374 eye-worms from the . . ... . . 383 giant strongyle found in the ..... 385 hsematozoa discovered by Sonsino in the .... 384 hydatids from the . . . . . .366 internal parasites of the ..... 357 plague, parasites not the cause of the .... 360 poultry lousiness of the ..... 388 psorospermial sac in the mitral valve of a . . . 281 scab or mange mites of the ..... 389 Sonsino's amphistomatoid fluke from the . . . 359 stomach-worms of the . . , . . ^ ./; . 380 tapeworm epizooty in the ..... 361 tick, the so-called . . ' '. . ' 'V ; ''' 388 worm-aneurism of the . . . *-' . . 368 Husk in young pigs caused by strongyles . . . .412 or parasitic bronchitis in cattle . _ . . . . 335 or verminous bronchitis in dogs ..... 304 Hydatid disease, deaths in Victoria from . . . .287 possibility of stamping out ; . ' . . . 141 Hydatids as the source of Tania echinococcus .... 113 exogenous, endogenous, and multilocular , . .115 frequently infest the head of the tibia . . . .129 hygienic considerations respecting . , . .126 in animals, Dr Cleghorn's statistics of . . . . 124 in Guy's Hospital Museum ..... 135 in King's College Anatomical Museum . . . 130 in Royal Veterinary College Museum . . . . 139 in St Bartholomew's Hospital Museum . . . 128 in St George's Hospital Museum . . . . 133 in St Mary's Hospital Museum .... 129 in St Thomas's Hospital Museum .... 134 in the Brighton and Sussex Hospital Museum . . . 136 in the Calcutta Medical College Museum . . . 137 in the Cambridge Anatomical Museum . . . 136 in the Charing Cross Hospital Museum . . . 131 in the London Hospital Museum .... 133 in the Melbourne Hospital Museum .... 141 in the Middlesex Hospital Museum .... 130 in the Norfolk and Norwich Hospital Museum . . . 137 in the Oxford Anatomical and Pathological Museum . . 136 in the Royal College of Surgeons Museum . . . 132 in the Westminster Hospital Museum .... 128 in University College Museum .... 131 in Victoria, number of deaths from .... 123 mortality in England from ..... 285 occupying the bones of cattle, specimens of . . 140 occupying the heart of a sow .... 139 occupying the nasal sinuses of a porpoise . . . 421 of animals in metropolitan museums .... 139 500 INDEX PAGE Hydatids of the tibia in the Nottingham Hospital Museum . .130 preserved in museums, their value .... 128 prevalence of, in Australia ..... 123 probable percentage of fatal cases of . . . .122 successful treatment of, by Mac"Gillivray . . . 128 their distribution in the organs of the body . . . 122 the so-called daughter vesicles of . . . 121 Hydrachnidce, a family of Arachnida . . . .5 Hymenolepis, as a new genus of cestodes '. j . . 102 Eyperoodon, Echinorhynchus found by Hyrtl in . . . 427 JSypertemia and Ancemia due to parasites . ' , . .213 Hyrax, parasites of the Cape . . . . . 403 Ichneumon, the Indian, fluke from the .... 299 Insectivora, entozoa found in the . . . . . 295 Insect parasites, various families of . . . . .6 Insects, entozoa of ...... 480 Intestinal worms, popular ideas respecting . . . .8 Itch or scab insect, description of the . . . . . 266 IxoAety species of, attacking man ..... 267 IxodidcB, a family of Arachnida . . . . .5 Jigger or chigoe as a human parasite ..... 274 Kaleege, worms from the black-backed .... 447 Kangaroo, tapeworm in the gall-bladder of a . . . 432 worms from the knee-joint of a . . . 433 Kestrel, entozoa from the ...... 447 Kite, entozoa from the . . . . . . 447 Klipdas (Hyrax), parasites of the . . . .403 Koala (Phascolarctos), tapeworm from a .... 432 KdlUkeriaJiUcollis, habitat of . . 462 Lagenorhynchus Eschrichti, worm found in . . . 421 Lambs, tapeworm epizooty in ..... 333 Lampyris, correction of an error respecting .... 483 Larvae of flukes, Pagenstecher's researches on . . . 452 Leeches considered as human parasites .... 258 of India, Ceylon, Japan, and Java .... 258 semiparasitic character of . . . .5 Lemurs, ccenuri or polycephalous hydatids in . . . 290 Leporines, acarine parasites of . . . . .319 Leptodera (Anguillula) stercoralis, description of ... 234 intestinalis, description of the . . . .235 Leptus autumnalis a human parasite ..... 268 Lernsoan parasites found on whales ..... 428 Lernceidcs, a family of crustacean parasites . . . .6 Leuciscus, the bleak, a possible source of tapeworm , . . 108 Leucochloridium, experiments by Zeller with , 435 Lice, various species found on man ..... 274 Ligula nodosa, as an immature Eothriocephalus . . . .110 INDEX 501 PAGE Ligula nodosa, the young state of Bothriocephalus . . . 470 simplicissima, researches by Duchamp on ... 469 Lindermannia proposed as a generic title . . . .7 Ling, Echinorhynchi in the . ... . . . 475 Lion, hydatids from the, in the Hunterian Museum . . . 189 Liofheida, a family of parasitic insects . . . .6 Liver fluke, the common, in man . . . . ,14 Louse of the elephant ...... 400 Lucilia hominivora, habits of the ..... 272 Lumbrici, geographical distribution of .... 247 in the Mauritius, remarks by Dyce on ... 247 remarkable cases of, in children ./ . . . 248 violent symptoms caused by . . . . . 249 Lumbricoid worms, poisonous effects produced by ... 250 Lungs of the porpoise, worms in the . ., . . 425 Maggots, rat-tailed, found in the horse .... 387 various species of, found in man .... 272 Malacoldellida, a family of suctorial annelids . . . .6 Manatees, parasites of the ...... 429 Marmoset monkeys, parasites of . . . .291 Marsupial animals, parasites of . . . . 430 Martens, internal parasites of ..... 298 Masuri and soorti, parasites of elephants .... 395 or amphistomes occur in man . . . .38 Measle-cysts in the Punjab, report respecting . . . .75 Measled cattle cured by removal from sources of infection . . 83 meat, Giacomini's observations on . . .65 Measles and bladderworms in cattle . . . . .61 and TcenicB, observations of Marchi on . . . .73 found in mutton brought to table . . . .97 of pork reared by experiment . . . .93 Meat question, the, in relation to " rot " . . . . 331 served as rations, Cysticerci in the . . . .78 Melolontha considered as an intermediate host .... 257 vulgaris as an intermediate " host " . . . . 413 Melophagus, a genus of parasitic insects . . . .6 Mermis albicans, development of . . . . 482 Messmates and parasites of mollusks ..... 480 Miana bug of Persia, or Argas ..... 267 Mice, internal parasites of . . . . . . 315 Micrococci considered as human parasites .... 277 Micropteron (Delphinus), flukes in . . . . 421 Mimetism favoring fluke development .... 436 Mite found upon Balcena australis . . . . . 428 Mole, parasites of the common ..... 296 Molluscs, entozoa of . . . . .480 Monads, parasitic forms of . . . . . . 282 Monkeys, hydatids obtained from ..... 141 parasites of ...... 289 502 INDEX PAGR Monodon monoceros, nematode worms of . . . 423 Monostoma plicatum from a northern whale .... 421 verrucosum, allusion to the eggs of . . . .41 MonostomidtB, a family of flukes . . . . .4 Mosquito, avian haematozoa in the . . . . 486 Mosquitoes of Queensland, filariae in the . . . 4S7 Mules, fatal epidemic affecting . . . . . . 382 Mitsca, larvae of, as human parasites . . . . 272 Musk-rat, cestode parasite found in the . . . . 296 Mutton measles, their existence denied '. . . 97 Narwhal, Prosthecotacter infesting the .... 423 Nematobothrium filarina, habitat of . . . . . 462 Netnatoda, families of the order of . . . , 4 Nematodes ahundant in marsupials ..... 433 Nematoids, opinion of Villot respecting the " free " . . 484 Nestlings destroyed by tapeworms ..... 440 Newts, ISchinorhynchtit anthuris of water .... 455 Nycteribiidce as parasitic insects . . . . .6 Octolothrium lanceolatum, allusion to the eggs of . .41 OdontoUus ceti from Balana australit .... 427 (Estridce, the, a family of parasitic insects . . . .6 ,, infesting the ox and sheep ..... 351 (Estrus (Qastrophilus) equi of the horse .... 385 hominis, Mr Higginson's case of . . . 271 Olulaniasis of the cat . . . . .310 Onchocerca reticulata of the horse ..... 385 Qnchotyle appendiculata from a dog-fish .... 464 Opossum, EcJiinorhynchus in a Brazilian .... 434 Opossums, flukes infesting American ..... 432 much infested by nematodes .... 433 Orcella Irevirostris, fluke found by Dr Anderson in . . 417 Orthagoriscvg mola as a " host " *. . . 471 Ostrich, entozoa from the American ..... 447 Otters, flukes and other entozoa of . . . . 298 Ox, insect parasites and tormentors of the . . . 351 species of Strongylus infesting the .... 347 Oxyurida, a family of round worms . . . , .6 Oxyurides, sanitary precautions in respect of . . . 232 source and mode of development of . . . 230 voluntary swallowing of human . . . .72 Oxyuris curoula of the horse ..... 380 vermicularis, description of the .... 227 Oysters as bearers of fluke larvae . . . . .26 Pachydermata, parasites of the . . . . 393 Palisade worms in relation to aneurism .... 368 Paramecium (Balantidium) coli of man .... 282 Paramecium, semiparasitic character of . . .7 Parasites from birds at the Zoological Gardens .... 117 INDEX 503 PAGE Parasites from cetacea in the Hunterian Museum . . . 427 in grouse from the Earl of Caw dor's estate . . . 439 of savages, little known respecting . . . ,27 popular delusions concerning . . . .1 their etiological significance not fully recognised . . 488 Partridge, entozoa of the ...... 440 Peccaries (Dicotylei), parasites of the .... 404 Pediculidce, a family of parasitic insects . . . .6 Pediculus, various forms of, infesting man . . 274 Pentastoma constrictum, description of the . 263 tcenioides as a human parasite .... 260 found in the horse , < i . 389 in the dog . , . , f . . . 306 Pentastomes infesting monkeys ..... 293 Pentastomidce, a family of Arachnida . . . ^ . ,5 Perch, flukes from the eye of the , ' " . . . . 458 Peritrachelius insignis from a dolphin .... 427 Pheasant, entozoa of the ...... 440 parasites from various species of . . 447 Philopteridcs, a family of parasitic insects . . . ,6 Phoccena communis, flukes found in . . . . 418 Phyllobothrium delpMni, source of . . . . 422 Pigeon, two hundred ascarides in a . . . , 442 Pig, hydatids from the, in the Hunterian Museum . . , 139 occurrence of Cysticerci in the brain of the ... 405 Pigs, the cause of " husk " in young . 412 Pike-whale, large fluke from the . . . . 421 Pike, worms from the urinary bladder of the .... 458 Pinnipedia, parasites of . . . . , 314 Pintado, ascarides in the vulturiue ..... 447 Physaloptera turgida infesting opossums . . . .433 Plagiotcenia gigantea of the rhinoceros . . . . 401 Plagues, parasites considered as a cause of . . . .2 Platanista gangetica, fluke from ..... 420 Podiceps and Gallinula, legs of, infested by filariae . . . 447 Polecats, filarize in the cranial sinuses of .... 298 Polystoma and Amphistoma of the frog .... 452 appendiculata, allusion to the eggs of . . .41 Polystomes, general characters of the ..... 463 Polystomidce, a family of flukes . . . . .4 Ponies, Welsh mountain, epizooty affecting .... 362 Porcupine ant-eater, tapeworm from the .... 433 Pork tapeworm, general description of the . . . .87 sources of infection by the . . . .94 Porpoise, flukes found in the common ..... 418 remarkable cestode from the common .... 422 worm from the tympanic cavity of the . . . 427 Porrlgo, mortality in England from ..... 285 Poultry lousiness not a human disorder .... 274 Proglottides mistaken for Dislomata . . . . .1.6 504 INDEX PAGE Prosthecoaacter, several species of . . . . 423 specimens of, in Hunter's Museum . . . 427 Proteles or earth-wolf, parasites of . . . . 299 Protozoa, parasitic families belonging to the . . .7 parasitic forms of, and gregarina . . . . 278 Psorospermia as a family of Protozoa ..... ^^P considered as human parasites .... 277 Psorosperms abundant in the hog . . . . . 414 in the flesh of animals . . . . . 281 Pulex penetrans, gigger or chigoe . . . 274 Pulmonary vessels of whales, worms in the . , . . 425 Pycnogonidce, a family of Arachnida . . . ^. .6 Quadrumana, entozoa and ectozoa of . . . . . 289 Quail, entozoa of the . . . . . 410 Queensland, Bancroft's collection of entozoa in . .431 Rabbits and hares, internal parasites of . . . .318 attacked by the autumnal spider .... 320 Caenuri found in the soft parts of . . . 333 Racoons, parasites infesting ... . 298 Rats, internal parasites of . . . . .316 Sedia and Cercarice, Pagenstecher*a remarks on ... 452 Redshank, entozoa from the ..... 447 Heduvius, or fly bug, various species of .... 274 Redwing, Echinorhynchi from a . . . . . 446 Reptiles, internal parasites of . . 451 Ehea Americana, filariro obtained by Darwin from . . . 447 Rhinoceroses, parasites of . . . . . 400 Ehopalophorus, a genus of flukeg ..... 432 Bhynchotteniada considered as a group . . .4 Rhytina stelleri, parasites of ..... 429 Rodentia, parasites of ... ... 315 " Rot " affecting the liver of porpoises .... 418 disease, conclusions respecting the .... 323 Round worms, various families of . . . .4 Ruminating animals, ectozoa found on .... 350 entozoa of . . . .323 Salmon, pit-headed tapeworms of the . Salmo umbla, worms in the kidney of .... 457 Sanguisuga medicinalis or the grey leech .... 258 Sanitation in connection with " rot " . Sarcoptes of the hog .... scabiei, description of the ..... 265 Savages, little known about the parasites of Scabies, mortality in England from . Scab or itch insect of man .... 265 Scalops canadensis, nematode found in 297 Schistosoma, considered as a synonym of Bilharzia . . .39 Sclerostoma and Anchylostoma as synonyms .... 211 INDEX 505 PAGE Sclerostoma dentatum of the hog ..... 412 pinguicola of Verrill, the so-called .... 409 syngamus in birds ..... 443 Seals and walruses, parasites of . . . . 314 Sheep, hydatids from cattle and . . / . . . . . 139 of New South Wales, fatal epizooty in . . . . 347 parasitic bronchitis affecting . . . . . . 335 whip-worms occasioning " scour " in . . . 349 Shrews, parasites known to infest ..... 296 Simondsia paradoxa, description of . . . . . 406 Simulium reptans or the creeping gnat . ' . . . 273 Skunk, tapeworm infesting the . . . . V * 298 Sloths, nematode worms found in - . . . < 322 Snake-birds, parasites in the cranium of . ' . . . 446 Snake, larval nematode from the heart of a , . . . 455 worms from an Egyptian hooded .... 456 Solidungula, parasites of the ..... 356 Solpugidce, a family of Arachnida . . . . .5 Soorti and masuri parasites of elephants . - . . 395 Sphcerularia bombi, Sir J. Lubbock's description of * -. ,t . . 481 found in various bees . .. u/ >*'< . . 480 Schneider's account of the development of . . . 482 Spirilla, found in the blood of fever patients .... 277 Spiroptera helicina in the feet of birds .... 440 megastoma of the horse . . . 380 sanguinolenta, Lewis's remarks on . . . . 303 sexalata infesting Dicotyles .... 407 strongylina of the hog ..... 406 Sporocysts or unorganised germ-sacs ..... 453 Squirrels, internal parasites of ..... 315 Stephanurus dentatus discovered by Natterer .... 407 Diesing's description of . . . . . 408 in Australia, announcement respecting . . . 409 in relation to porcine epizooty .... 411 Nattereri, proposed synonym .... 412 Professor Fletcher's account of . . . . 411 rediscovered by Dr. White . . . . 409 Sticklebacks, Gyrodactylus from the tail 'of . . . .466 Stoat, parasites found in the common .... 299 Stomoxys calcitrans, or the leg-sticker . . . . 273 Strongyle, meaning and origin of the term . . . .4 Strongyles, Welsh equine epizooty from .... 377 Strongylidce, a family of round worms . . . .6 Strongylus acuticaudatus from a Tinamou .... 447 armatus of the horse ..... 367 dentatus confounded with Stephanurus . . . 412 (Eustrongylus) gigas, found in man .... 208 filaria, experiments by Leuckart with . . . 337 temperature necessary to kill the . . .70 micrurus, or cattle lung-worm .... 335 33 506 INDEX PAGE Strongylus vnicrurus, original experiments with .... 337 minutissimus in Algerian sheep .... 346 Pallasii from Beluga leucas .... 427 paradoxu* a cause of husk . . . . .412 pergracilis and the grouse disease .... 439 tetr 'acanthus, larvae of , , , . 374 Sturgeon, Echinostoma hispidum from a 462 Suidce, rarity of flukes in the . . 404 Sun-fish, Tetrarhynchus infesting the . . , . . 471 Swine Breeders' Association, U.S. National . . . .412 external parasites of . . . , . . 414 internal parasites of . . . . . . 404 Sword-fish, parasites of the . , . , , . 458 Sydney, entozoa collected by Krefft and Masters near . . .431 Syngamus (Sclerottoma) trachealis ill birds .... 443 Syrphida include rat-tailed maggots . . , . .7 Tachyglossus setonu, tapeworm found in .... 433 Tacuschi, parasites of the so-called , 417 Tapeworm, Culliugwortb's monstrous variety of 103 ,, from the vulpine opossum ..... 432 in the Baikal, statements of Kaschm respecting . . 82 ,, mortality in England from .... 285 the broad, derived from fish , 107 Tapeworms infesting marsupials ..... 432 injurious to avian bearers ..... 438 (Ligula) causing piscine epizooty* .... 469 of the dog . . . . . 300 symptoms occasioned by . . . . .90 various families of . . . .4 Tapir, parasites of the American . . 402 Tcenia abietina, a variety of T. mediocanellata .... 102 acanthotrias, remarks on the so-called .... 103 and cysticercuSy coexistence of . . . . .94 angulata in nestling blackbirds ..... 440 bipapillosa from the wombat . . . . .432 calva and the grouse disease ..... 439 canina identical with T. elliptica . . . .101 crassicolUs, its source suggested by Goeze . . .57 possessing two heads .... 105 cyathiformis, allusion to the eggs of . . .41 echinococcus, its prevalence in Iceland . . . .125 reared from hydatids . . . .113 elliptica as a human parasite ..... 101 festiva in Macropus and Kdlmaturus .... 432 flavopuncta, brief description of the .... 101 from the Cape of Good Hope, variety of . . . . 104 geophiloides a new tapeworm ..... 432 lata of Pruner, probable synonym of . . .96 lophosoma, considered as a species . . . .99 INDEX 507 PAGE Tcenia Madagascar 'iensis, brief description of the . . . 100 magna of the rhinoceros ..... 401 marginata, as a human parasite .... 100 mediocanellata, description of the . . . .56 Cullingworth's specimen of . .99 feeding experiments with . . .58 Mussulmans infested by . . . .78 vnegaloon, doubtful character of the . . . 105 nana, brief description of the ..... 100 perfoliata, temperature necessary to kill the . . . 70 phalangista from the vulpine opossum .... 432 phoptica, a new tapeworm . . . . . 433 remarkable Hunterian specimen of . . . 102 saginata, considered as a synonym . . . .57 serrata, temperature necessary to kill . . . .69 solium, general description of the . . . .87 ,, sources of infection by . . . . .94 ,, tenella, probable source of the . . . . .95 variabilis, allusion to the eggs of . . .41 Tetrarhynchi of sharks and rays ..... 470 Tetraphyllobothridce, a family of tapeworms . . . .4 Tetrarhynchus reptans of the sun-fish .... 472 Tenches destroyed by Ligulce ..... 469 Tetrastoma renale, notice of the so-called . . . .36 Tetrabothrium triangulare, from Delphinus .... 422 Thecosoma considered as a synonym of Silharzia . . .39 Thorn-headed worms resemble nematodes . . . .5 Thread-worm, description of the common .... 227 Tinamou, worms from the . . . . . . 447 Tongues of living animals inspected for " cyst " . . .80 Tope, or penny dog-fish, Tetrarhynchus of the .... 471 Trachearian arachnida, parasitic families of . . .5 Trematoda, families of the order of . . . . .4 Trematode-larva), Pagenstecher's reseaches on . . . . 452 Trernatodes infesting opossums ..... 432 Trianophortis nodulosus with two heads .... 105 Trichina affinis, the so-called ..... 406 spiralis, discovery of, in man .... 194 description of the mature . . . .153 experiments conducted in England with . . Il>7 ,, in relation to diseased meat .... 166 temperature necessary to kill the . . .70 Trichinida form a family of round worms . . . .5 Trichinosis in animals, symptoms of . . . . , 163 in England, an outbreak of .... 169 in Germany, outbreaks of .... 168 Trichocephalidae, a family of round worms . . . .5 Trichocephalus affinis in sheep ..... 349 crenatus of the hog . . . . 406 dispar, description of the . . . . 178 508 INDEX PAGE Trichosoma, new species found by Solger . . . 456 Tricuspidaria nodulosa, with two heads .... 105 (Tricenophorus) nodulosa infesting fishes . . . 470 Tristomes not strictly entozoa ..... 463 TristomidcB, a family of flukes . . . . .4 Trout, EchinorJiynchi in the ..... 475 the, a probable source of Sothriocephalus . . . 470 Tsetse fly fatal to the horse . . .' . . .388 Turbellarians, remark concerning the . . . .8 Turbot, Echinorhynchi in the . ... . * . 475 Turkeys, water, parasites found by Wymau in . . . . 446 Turtle, worms from a snapping . . . , . . . 455 Tympanum of whales, worms in the cavity of the ... 425 Tyroglyphu* Mtricourti of Laboulbene . . . . 266 Urobales palustris in connection with the guinea-worm . . . 219 Udonella caligorum, peculiar habit of . . . . . 484 ,, mode of development of . . . . 463 Wagtail, flukes reared by Zeller in the . . . . 436 Wallaby, Filaria from the abdomen of a . . . .433 tapeworms observed iu the ..... 432 Warblers, development of flukes in . . . . 435 Warbles formed by the larva} of (Estrus .... 351 Wasps ( Vespa), Spheerularia in . . . .481 Water-hen, worms found in the legs of the .... 447 Water- turkeys, worms in the cranium of .... 446 Weasles, internal parasites of ... . 298 source of tapeworms in . . . . 296 Whale-lice (Cyami and Pycnogonidae) ..... 428 w (Cyamidte), zoological position of . . . .5 Whale-worms found by John Hunter ..... 427 Whales, ectozoa of . . . . . .428 internal parasites of ..... 416 Whip- worm (Trichocephalus) of the hog .... 406 White-throat, flukes reared by Zeller in the . . . . 436 Wombat, tapeworm found in the . . . 432 Worm-aneurism, Bellinger's researches on . . . 368 Worm-like sac in the mitral valve of a horse .... 281 Worms are not a criterion of previous disease . . . .435 from the heart of a guillemot ..... 447 infesting the Virginian opossum .... 433 in the knee-joint of a kangaroo .... 433 in the tympanic cavity of whales .... 425 in whales, found by John Hunter .... 427 mortality in England from . . 285 of the kangaroo in the Hunterian Museum . . . 433 Zebra, hydatids from the liver of the . . . . .366 from a, described by Huxley . . . .117 PKINTED BY J. B. ADLABD, BABTHOLOMEW CLOSE. I /I / fr