Of the numerous insect parasites and tormentors of solipeds the gadflies (Œstridæ) 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 larvæ make their escape. As maggots they are next transferred to the mouth, and ultimately to the stomach along with food and drink. A great many larvæ perish during this passive mode of immigration, some being dropped from the mouth, and others being crushed in the fodder during mastication. It has been calculated that out of the many hundreds of eggs deposited on a single horse, scarcely one out of fifty of the larvæ 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 fæces. 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 larvæ 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 larvæ of Œstrus 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 1876 that he had a drove of foreign ponies under his care, all of which suffered irritation from hæmorrhoidal 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 larvæ of G. hæmorrhoidalis 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 larvæ of G. nasalis commonly reside in the duodenum near the pylorus. According to Schwab and Brauer, they rarely occupy the stomach. As occurs in the common species, this bot passes away with the fæces, 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-larvæ 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-mentioned 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. (Œstrus) veterinus, G. ferruginatus, G. jubarum, G. (Œ.) 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. Brückmüller published a case where the brain was infested by larvæ; and Mr Shipley has sent me an example of H. equi, which he states he removed from the choroid plexus of the brain. In addition to the cases by Woods, Goodworth, and Brewer, already quoted, others have been published by Tyndal and Cartwright.
Amongst the numerous other parasitic dipterous larvæ 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 Cœnurus. I have previously mentioned my having received an Helophilus-larva that had passed from the human body. One of the most troublesome 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 Stackra, 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 (Glossina 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 (Hæmatopota pluvialis) which is very abundant in the West Highlands, various species of Tabanidæ and Asilidæ (Tabanus autumnalis, T. bovinus, Chrysops cæcutiens, Asilus crabroniformis), and also a host of ordinary flies and gnats (Muscidæ and Tipulidæ), 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 (Anoplura) 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, Hæmatopinus equi, H. vituli, H. eurysternus, and the ass-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 account of cases of lousiness due to Hæmatopinus I am indebted to Mr S. Butters. As regards the scab, itch, and mange insects or mites (Acaridæ), three perfectly distinct forms are known. Adopting M. Mégnin’s classification they are Sarcoptes scabiei, var. equi, Psoroptes longirostris, var. equi (being the Dermatodectes equi of Gerlach), and Chorioptes spathiferus, var. equi, which is the Symbiotes equi of Gerlach. All the species have been beautifully illustrated by M. Mégnin, whose memoir has dispersed many of the clouds of error and misrepresentation 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 Mégnin in respect of the structure 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 Ixodidæ, known to infest other animals, behave in the same way. The Arachnidan called Pentastoma tænioides, 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. Rose, whose writings I have frequently quoted in connection with the Cœnuri of rabbits.
Bibliography (No. 50).—Aitken, J., “Worms in the Spermatic Artery of a Colt,” ‘Veterinarian,’ p. 683, 1855.—Anderson, J., “A Case of Strangulation of the Ileum (with Lumbrici),” ‘Veterinarian,’ p. 261, 1859.—(Anonymous), “Rupture of the Stomach, associated with the existence of Cysts between its Coats containing Worms,” ‘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,’ 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., tom. x, p. 345.—Bollinger, O., ‘Die Kolik der Pferde und das Wurmaneurisma der Eingeweidearterien,’ Munchen, 1870. (Reviewed by myself in the ‘Veterinarian,’ Jan.–April, 1874.)—Bovett, “Existence of Filariæ in a Sinuous Ulcer of the Withers of a Mare,” ‘Veterinarian,’ p. 515, 1861.—Bradshaw, C., “Death of Mules from Parasitic Disease in the Mauritius (with remarks by Dr Cobbold),” ‘Veterinarian,’ Dec., 1876, p. 837.—Brauer, F., ‘Monographie der Œstriden,’ Wien, 1863.—Idem, “Œstr. (Hypoderma) Clarkii,” in ‘Verhandl. 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. S., “The Œstrus equi, or Horse-bot,” the ‘Veterinary Journal,’ July, 1877, p. 14.—Brückmüller, “Larvæ in the Brain of a Foal,” from ‘Viert. für 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,” ‘Veterinarian,’ p. 413, 1833.—Idem, “Case of about 200 ‘Bots in the Œsophagus’ of a Horse,” ibid., p. 400, 1828.—Chambron, “On a Parasitic Malady in the Horse,” from ‘Ann. de Méd. Vét.,’ in ‘Edin. Vet. Rev.,’ 1861; see also (Cambron) ‘Veterinarian,’ 1860, p. 612.—Clark, B., “Obs. on the genus Œstrus,” ‘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., 1845.—Cobbold, “On the Diptera (bots),” in a chap. on the Parasitic Diseases of Animals, in Williams’ work (l. c., Bibl. No. [48]).—Idem, “Obs. on rare Parasites from the Horse,” ‘Veterinarian,’ 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 Mégnin’s Tapeworm,” ibid., Sept., 1874.—Idem, “Report on Parasites (sent from India by F. F. Collins and Spooner Hart),” ibid., Nov., 1874.—Idem, “Epizoöty 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 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,” ‘Veterinarian,’ p. 145, 1857.—Coupe, W., “Fatal Parasitism in a Colt,” ‘Veterinarian,’ Dec., 1876, p. 844.—Davaine, “Les Cestoides,” in ‘Dict. Encycl. des Sci. Méd.,’ p. 591.—Dick (see Knox).—Dickens, C., “Joint-lameness in Colts, associated with and symptomatic of Lumbricoid Worms,” ‘Veterinarian,’ p. 601, 1863.—Dun, R., “Remarks on Entozoa of the Horse,” ‘Veterinarian,’ 1854, p. 445.—Dupuy (with M. Prince), “Filariæ in the Great Mesenteric of a Horse,” ‘Veterinarian,’ 1835, p. 570.—Emmerson, C., “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, 1837.—Grellier, J., “On the Worm in the Eye (of the Horse),” ‘Veterinarian,’ p. 18, 1844.—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,” ‘Veterinarian,’ 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 ‘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].—Jeaffreson, 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 pellucidus) 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 (l. c., in text).—Lee, C. A., “On Filaria papillosa in the Anterior Chamber of the Eye of a Horse (and on Filariæ in general, &c.),” ‘Amer. Journ. Sci. and Art.,’ vol. xxxix, p. 278, 1840.—Lessona, G., “On the Bot (or Œstrus) of the Horse,” from ‘Recueil de Méd. Vét.,’ in ‘Veterinarian,’ p. 156, 1854.—Leuckart (l. 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,’ 1843, p. 648.—Mégnin, “Petit Tænia inorme du Cheval,” in ‘Bull. de la Soc. Cent. de Méd. Vét.,’ t. vi, 3e série, 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, J., “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.—Molyneux, 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’ (l. c., Bibl. No. [49]), p. 263.—Peall, 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, C., “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. 358, 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.—Tyndal, J., “Worms in the Intestines of a Mare,” ‘Veterinarian,’ 1843, p. 629.—Twining, W., “Obs. on the Filaria or Threadworm 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, “Perforation of the small Intestines by Ascarides lumbricoides (in the Horse),” from ‘Rec. de Méd. Vét.,’ 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, R. G., “Parasites in the Kidneys of a Mare,” ‘Veterinarian,’ 1866, p. 265.—Woodger, “Hydatid in the Brain of a Horse,” ‘Veterinarian,’ 1863, p. 75.—Woods, J. S., “Tetanus in a Mare, associated with the Larvæ of Œstrus 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,” ‘Veterinarian,’ 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, 1832.—Zangger, “Remarks on Entozoa,” from the French, ‘Veterinarian,’ 1855, p. 463.
Part X (Pachydermata)
Concerning the parasites and parasitic diseases of this miscellaneous assemblage of large mammals, I shall first speak of those of the proboscideans (Elephantidæ). 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:—Fasciola Jacksoni (mihi), Amphistoma Hawkesii (mihi), Ascaris lonchoptera (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, 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 papillæ about midway between it and the ventral acetabulum; intromittent organ 1/4″ in length; digestive apparatus with two main zigzag-shaped canals, giving off alternating branches at the angles thus formed, the ultimate cæcal ramifications occupying the whole extent of the body; length, when unrolled, from 1/2″ to 5/8″, breadth 1/3″ to 1/2″.” 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 Distomidæ,” which appeared in the ‘Journal of the Linnean Society’ for 1861, I had also placed it amongst the distomes, not considering it 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 R. 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 containing three bottles, one containing the liver-fluke (Fasciola Jacksoni) referred to in your work on the parasites of domesticated 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 earth, 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 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 Rudolphi; 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 fæces. 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 ‘Highlands 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.
General Hawkes afterwards supplied me with further information. 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 fæces 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 scientifically 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 circumstances, 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 ‘fasting,’ and bears testimony to the generally received notion of the necessity of withholding the rice when the animal is eating earth.”