Chapter XIV: Section III: NEMATODA (Round Worms) (2)

“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 appearance 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 precise, 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 happened that this poor pig became trichinised. In my communication 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 Trichinæ. 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. 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 absolutely 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:--‘Are there any sources of comfort to be gathered from the facts?’ Or you may say, supposing that in future our British swine are not as free from Trichinæ as they have been hitherto, can we possibly avoid the contingency of playing the part of host to those creatures? Certainly, I reply, it is simply a question of properly cooking 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 Trichinæ 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 Trichinæ 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 Trichinæ present, and yet the man survived the attack.

“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 infection. It is something to know what you are either handling or looking at, because there are many parasites besides Trichina 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-Trichinæ, after they have arrived at their destination within the flesh of man, are capable of producing any more unfavorable consequences? The answer is, Certainly not. In the case of man it would be necessary that his muscles should be eaten in order for the Trichinæ 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 sometimes twice a day, sausages made from the flesh of the trichinised 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 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 disease 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, G. J._, “Exhib. of Specimens,” ‘Micr. Jrn. and Structural Record,’ 1842, p. 94.--_Althaus, 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.--_Belfield_ (with _Atwood_), “Trichinæ in Pork;” ‘New York Med. Rec.,’ Dec. 28, 1878; ‘Med. Times and Gaz.,’ Feb. 15, and ‘Lancet,’ Feb. 22, 1879.--_Bellingham, O. B._, ‘Dublin Med. Press,’ 1852.--_Bowditch, H. J._, “Cases of Trichina,” ‘Boston Med. and Surg. Journ.,’ 1842-43-44.--_Bristowe, J. S._ (and _Rainey_), ‘Trans. Path. Soc.,’ 1854.--_Chevers, N._, “Sanitary Efforts in regard to Trichiniasis,” ‘Lancet,’ 1864, vol. ii, p. 733.--_Cobbold, 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, 1873, p. 46; also in the ‘Veterinarian,’ March, 1874.--_Idem_, Remarks 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 Ruminants 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” (l. c., Bibliog. No. 2, Lecture xviii), 1872.--_Idem_, “Outbreak of Trichinosis in England,” ‘Brit. Med. Journ.,’ 1871, p. 435.--_Idem_, “Trichinæ 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, C._, 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_, “Trichinæ 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._, ‘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_, “Trichinæ in the Badger,” ‘Assoc. Med. Journ.,’ 1853, p. 491.--_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._, “Trichiniasis,” 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 Hedersleben Epidemic,” ‘Brit. Med. Journ.,’ 1866, p. 76.--_Krombein_, “Trichiniasis in New York,” ‘Amer. Journ. Med. Sci.,’ 1864, and ‘Med. Times and Gaz.,’ 1864, p. 292.--_Küchenmeister, F._, Symptoms, &c., ‘Lond. Med. Rev.,’ 1860, p. 457.--_Langenbeck_, case, ‘Edin. Vet. Rev.,’ Feb., 1864.--_Leidy, J._, “Trichina in 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.--_Mosler_, “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.--_Salisbury, 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. lxiii, 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, 1860.--_Wedl_, Report, ‘Brit. Med. Journ.,’ Dec., 1866, p. 618.--_Wilks, S._, “Letter respecting the Discovery of Trichina,” ‘Lancet,’ March 10, 1866, p. 269; see also the ‘Times,’ Feb. 13, 1866.--_Windsor, J._, ‘Brit. Med. Journ.,’ March 4, 1866, p. 319.--_Wood, H._, case, ‘Lond. Med. Gaz.,’ 1835.

_Foreign Literature_:--_Ardenghi, E._, “Sulla _Trichina spiralis_,” ‘Lo Studente Veterinario,’ 1876, p. 115.--_Behrens_, “Ein Fall von Trichiniasis,” ‘Deutsche Klinik,’ No. 30, 1863 (quoted by Davaine).--_Bette, F._, _ibid._, 1876.--_Bischoff_, ‘Path. Anat. des menschl. Körp.,’ 1845.--_Idem_, ‘Med. Annalen,’ 1840.--_Böhler_, ‘Die Trichinenkrankheit in Planen,’ 1863.--_Boudin_, “Des épidémies de Trichina spiralis observées en Allemagne dans ces dernières années,” ‘Journ. de Méd. Vét. Milit.,’ August and September, 1864 (quoted by Davaine).--_Claus_, ‘Wurzb. nat. Zeitschr.,’ 1860.--_Idem_, ‘Ueber die Trichine’ (a discourse), 1877.--_Colberg_, ‘Deutsche Klinik,’ 1864.--_Davaine, C._, ‘Traité’ (l. c., Bibl. No. 1), 1860, p. 672, 2nd edit., p 732-768.--_Idem_, “Faits et Considerations sur la Trichine,” ‘Mémoires de la Société de Biologie’ for the year 1862, tom. iv, ser. 3, 1863; in ‘Gazette Médicale de Paris,’ 1863; in ‘British Medical Journal’ for April 25, 1863; and in my ‘Entozoa,’ p. 349.--_Idem_, “La Trichine” (popular exposition), in ‘Revue des Deux Mondes’ for May, 1865.--_Dujardin_ (l. c., Bibl. No. 1), p. 24.--_Fiedler_, ‘Virchow’s Archiv,’ 1864.--_Fleckles, F._, ‘Die Trichinen und die Trichinenkrankheit’ (popular exposition), Prag., 1866 (quoted by Davaine).--_Friedrich, N._, ‘Virchow’s Archiv,’ 1862.--_Fürstenberg_, “Wochenblatt d. Ann. der Landwirthsch., in d. Königl. Preuss. Staaten,” 1865.--_Gerlach, C._, ‘Die Trichinen,’ 1866.--_Idem_, ‘Hannöversche Zeitschrift,’ 1864.--_Hagen_, in ‘Pharmaceutische Centralhalle,’ 1862.--_Henle_, ‘Muller’s Archiv,’ 1835, s. 526.--_Herbst_, ‘Nachrichten v. d. Georg-Aug. Univ. zu Göttingen,’ 1852; ‘L’Institut,’ 1852, p. 135.--_Heschl, R. L._, ‘Ueber Trichinen, die Trichinenkrankheit und die Schützmassregeln dagegen,’ Gratz, 1866 (quoted by Davaine).--_Kestner_, “Etude sur le Trichina,” ‘Gaz. Méd. 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 Vet.,’ 1872.--_Kratz_, ‘Die Trichinenepidemie zu Hedersleben,’ 1866.--_Küchenmeister_, ‘Parasiten,’ 1855.--_Leuckart_, ‘Untersuchungen ueber _Trichina spiralis_,’ 1866.--_Idem_, ‘Die mensch. Par.,’ Bd. ii, s. 409.--_Idem_, “Die neuesten Entdeckungen ueber menschliche Eingeweidewürmer und deren Bedeutung für die Gesundheitspflege,” ‘Unsere Zeit.,’ 1862.--_Lion_, ‘Zur Geschichte, Therapie, Prophylaxis, und Sanitätspolizei der Trichinen’ (quoted by Pagenstecher).--_Luschka_, “Zur Naturgeschichte der _Trichina spiralis_,” ‘Zeitschr. für wissenschaftl. Zool.,’ 1851.--_Meissner_, ‘Zeitschr. f. rat. Med.,’ 1855.--_Idem_, “Ueber Trichinenkrankheit,” ‘Schmidt’s Jahrbücher,’ 1863.--_Ordonez, E. L._, ‘Note sur la Distinction des Sexes et le Développement de la Trichina spiralis des Muscles,’ Paris, 1863; and ‘Compt. Rend. Soc. Biologie,’ p. 61, 1863 (quoted by Davaine).--_Pagenstecher_, ‘Verhandl. d. Naturhist.-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, 1877.--_Reyher, O._, ‘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_, ‘Ueber die Trichinenkrankheit und ihre Vermeidung,’ Jena, 1863.--_Siebold_, art. “Parasiten,” ‘Wagner’s Handwörterbuch,’ 1844.--_Simon, G._, “Eine Trichinen-epidemic in Calbe,” ‘Preussische Medicinal Zeitung,’ 1862.--_Tommasi_, ‘La Trichina spiralis e la Malattia prodotta da esso,’ Torino, 1863.--_Tüngel_, ‘Archiv von Virchow,’ xxvii, 3, 421, 1863 (quoted by Davaine).--_Virchow_, ‘Deutsche Klinik,’ 1859; ‘Comptes Rendus de l’Acad. des Sci.,’ tom. xlix.--_Idem_, ‘Archiv f. Path. Anat. und Physiol.,’ Bd. xviii.--_Idem_, ‘Darstellung der Lehre von den Trichinen’ (fur Laien und Aerzte), 1864.--_Vogel_, ‘Die Trichinenkrankheit,’ 1864.--_Wagner_, “Eine Trichinenepidemie in Leipzig,” ‘Arch. der Heilkunde,’ 1864.--_Wunderlich, C. A._, “Sur la diagnose probable de l’affection trichinale,” ‘Gaz. Méd. de Paris,’ p. 311, 1863; from ‘Wagner’s Archiv der Heilkunde,’ ii, 3, p. 269, Leipzig, 1861 (quoted by Davaine).--_Zenker_, “Zur Lehre von der Trichinenkrankheit,” ‘Deutsches Archiv. für 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 longitudinal band of minute wart-like papillæ. The tail of the male 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 1/480″ to 1/447″ in their long diameter. The whipworm infests the cæcum, and also the upper part of the colon. Upwards of one thousand were found by Rudolphi 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 calculates 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 Rennes 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 investigated by Dujardin, Mayer, Von 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 Küchenmeister that there are no external appendages in the female _Trichocephalus_ comparable to those known to exist in the allied _Trichosomata_, is incorrect. Leuckart’s, and especially Virchow’s, researches disproved Küchenmeister’s and Meissner’s notion that _Trichinæ_ 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 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 1/333″ in length, and resembles the parent to a certain extent.

Whipworms rarely put their bearers to inconvenience; nevertheless, 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. 545.--_Bellingham, O. B._, “On the frequency of _Trichocephalus dispar_ in the Human Intestines,” ‘Rep. of Brit. Assoc., in Dubl. Journ.,’ 1838, and in ‘Med. Chir. Rev.,’ 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.--_Chiaje_, sul _Tricocephalo disparo_, &c., 1836.--_Cobbold_, ‘Entozoa,’ pp. 69 and 329.--_Idem_, ‘Worms,’ pp. 31 and 67.--_Davaine_, l. c., p. 205.--_Idem_, ‘Compt. Rend.,’ 1858, p. 1217, and ‘Journ. de Physiol.,’ 1859, p. 296.--_Dubini_, ‘Entozoografia umana,’ p. 83.--_Dujardin_, l. c., p. 32.--_Eberth_, “Die Generationsorgane von _T. dispar_,” ‘Sieb. und Köll. Zeitschr.,’ 1860, s. 384.--_Gibson, D._, “On a Case of Paralysis, with loss of speech, from intestinal irritation (produced by _T. dispar_),” ‘Lancet,’ Aug. 9th, 1862, p. 139.--_Goeze_, ‘Naturg.,’ s. 112.--_Gurlt_, ‘Path. Anat.,’ p. 350.--_Küchenmeister_, l. c., s. 235; Eng. edit., p. 321.--_Leidy_, ‘Proc. Acad. Phil.,’ viii, p. 53.--_Leuckart_, l. c., s. 465.--_Mayer_, Sieb. und Köll. ‘Zeitsch. f. wiss. Zool.,’ Bd. ix, s. 367; Bd. x, s. 233, and s. 383, 1858-60.--_Mérat_, ‘Dict. Sc. Méd.,’ 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 _Trichina spiralis_. Step by step the facts have been evolved by a slow process of observation, and from the data thus afforded a tolerably connected narrative of the probable life-cycle of this 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 philosophic naturalist. In the case of Trichina, Owen’s nomenclature 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 hæmatozoon 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 papillæ. 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, 3-1/2 in.; breadth, 1/90″; embryos, 1/200″ to 1/125″ in length, by 1/3000″ to 1/2250″ in breadth; eggs, averaging 1/1000″ by 1/1650″ 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 hæmatobia_, 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 formulated in the following manner his judicious and prudent conclusions:--It would be rash on my part to put forth a conjecture on the coexistence of these worms of the hæmatochyluria, 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 hæmaturic, 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 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 hæmaturia in the last-named case, which Dr Salisbury describes as one of “cystinic rheumatism,” or “severe cystinæmia 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 (× 300 diam.), and one representation of the embryo (× 1000 diam.). If these figures give the size correctly, the ova measure only about 1/800″ in length, by 1/1560″ in breadth, whilst the embryo would be about 1/500″ from head to tail.

On the 17th of May, 1872, I communicated to the Metropolitan Counties Branch of the British Medical Association a paper on ‘_Bilharzia_,’ 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 perfectly spherical, with a well marked chorional envelope and double contour. These forms measured about 1/750″ in diameter. The fully grown eggs observed at the same time gave a longitudinal measurement of 1/500″ by 1/1000″ in breadth. On adding any stimulus, such as diluted sulphuric acid, the embryos moved themselves freely within the egg. After allowing the 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 envelope. In this state they were easily separated and examined, when they gave a measurement of 1/300″ in length, by 1/3500″ in breadth. On two occasions, whilst engaged in rearing the larvæ of _Bilharzia_ in water, I noticed single specimens of these embryos lying dead; and one of the examples thus observed gave a length of 1/150″, by 1/3000″ in 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. Accordingly, 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 O. 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 hæmaturia. He also afterwards found them in a man whose urine was slightly chylous, but not hæmatic. 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 Crévaux in a hæmato-chylurous patient at Guadeloupe. Dr Crévaux frequently examined the blood of this patient but found no hæmatozoa. 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 hæmaturia, 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 Filariæ 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 hæmatozoon Lewis gave the trinomial term _Filaria sanguinis hominis_, which thus fitly distinguished it from the _Filaria papillosa hæmatica canis domestici_ described by Grube and Delafond. Dr Lewis found the average size of the parasite to be 1/75″ in length by 1/3500″ 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 Filariæ 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 Filariæ 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 human body. On this point Lewis remarks:--“Not only may those hæmatozoa 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 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 Hæmatozoa 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 hæmatozoology 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 hæmatozoa abroad.

On the 20th of April, 1874, Dr Prospero Sonsino communicated to the Neapolitan Royal Academy his memoir entitled “Researches concerning _Bilharzia hæmatobia_ in relation to the endemic hæmaturia of Egypt, with a notice concerning a nematoid found in the human blood.” In this brochure he made known the fact of his having discovered microscopic Filariæ 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 hæmatic corpuscles. The worms glided amongst the globules, which were tossed about by their lively movements, showing various appearances 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, subsequently 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 Filariæ 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 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 Filariæ 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 Filariæ. 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 Filariæ, three of which I sketched _in sitû_, 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 1/500 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 Filariæ 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 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 hæmaturia, 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 Filariæ 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 condition it could be easily washed out of hydroceles through a large-sized trochar from patients known to suffer from Filariæ.”

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 announcement 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.” 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.

When (prior to Lewis’s discovery of the hæmatozoa) 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 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 Filariæ, and also eight bottles filled with various intestinal worms taken from animals. The Filariæ 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 1/90″ 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 complete 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 1/20″ from it), the anal orifice being placed within the 1/90″ from the extremity of the tail. The vaginal pouch, 1/100″ 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 1/10″ from the head. Towards the tail a fold of the tuba Fallopii was seen to extend to within 1/20″ 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 1/125″ in length by 1/2500″ in breadth. They 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 1/200″ in length by 1/3000″ 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 1/900 to 1/1000 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 (Brisbane, 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 hæmatozoal 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 hæmatozoa, it never once occurred to me that the numerous nematoid embryos mixed with the Bilharzia ova were hæmatozoal. 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 inference was wrong, but it has instructively shown how near one may go towards a great discovery without really making it. As regards the larvæ, 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, Crévaux and Corre, Silva Lima, Bancroft, Manson, 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 parasites appear to be associated with, if not actually the cause of, 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 Hæmatozoa, by Dr Patrick Manson, of Amoy, China, this careful observer gives interesting particulars of no less than fifteen cases in which hæmatozoa 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 remaining 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 ordinarily termed “good health” is rarely associated with a hæmatozoal condition of the blood in the human subject. The cases given by Lewis and Manson, where absolutely no recognisable disease existed, must be regarded as exceptional. Disease, moreover, may exist without any palpable symptoms being exhibited by the “bearer,” and thus perhaps it was with the hæmatozoal 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 Filariæ in their blood appeared to suffer no inconvenience whatever.

In the autumn of 1877 Dr Da Silva Lima published an article in the ‘Gazeta 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 insufficiently acknowledged Wucherer’s claims. A translation of this article appeared in the ‘Archives de Médicine Navale,’ with an important appendix by Dr le Roy de Méricourt. 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-Filariæ, 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 Roy de Méricourt appeared in the ‘Lancet’ for Jan. 5th, 1878, and I also published a full translation 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 Bancrofti_) 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 larvæ of _Filaria sanguinis hominis_ in the stomach of mosquitoes. Already, in April, 1877, Dr Bancroft had informed me of his expectation of finding that these insects sucked up the larvæ 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 hæmatozoa, 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 hæmatozoa occurring in Chinese subjects, together with additional particulars of one of the cases already published in the ‘Customs Gazette.’ These were afterwards published as separate contributions in the ‘Medical Times and Gazette.’ Dr Manson likewise forwarded 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 hæmatozoa, and he added valuable statistical evidence as to the prevalence of Filariæ 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 Manson’s investigations relating to the metamorphoses undergone by the Filariæ within the body of the mosquito. In this paper Manson pointed out 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 Filariæ 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 Filariæ, 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 Filariæ, 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.