171 Notwithstanding the progress made during the last decades, the ova of helminthes and more particularly of trematodes, have been mistaken for Coccidia. Thus Poschinger (Zool. Anz., 1819, ix, p. 471) and Gebhard (Virchow’s Arch., 1897, No. 147, p. 536) mistook the ova of Distoma turgidum, Brds., for Coccidia. Podwyssotzki (Centralbl. f. allg. Path., 1890, i, p. 135) made a similar error with the ova (and vitelline sacs) of a species of Prosthogonimus (Distoma ovatum of the authors); von Willach (Arch. f. wiss. u. prakt. Thierheilk., 1892, xviii, p. 242) mistook the ova of a nematode for Coccidia.

172 The life-cycle given here is based on that of Eimeria (Coccidium) schubergi, after Schaudinn (1900). See “Untersuchungen über den Generationswechsel bei Coccidien,” Zool. Jahrb., Abt. f. Anat., xiii, pp. 197–292, 4 plates.

173 Arch. f. Protistenkunde (1911), xxii, p. 71.

174 Fantham, H. B. (1910), “The Morphology and Life History of Eimeria (Coccidium) avium, a Sporozoön causing a fatal disease among young Grouse,” Proc. Zool. Soc. Lond., 1910, pp. 672–691, 4 plates. Also Fantham, H. B. (1911), “Coccidiosis in British Game Birds and Poultry,” Journ. Econ. Biol., vi, pp. 75–96.

175 Fantham, H. B. (1910), “Experimental Studies on Avian Coccidiosis, especially in relation to young Grouse, Fowls and Pigeons,” Proc. Zool. Soc. Lond., 1910, pp. 722–731, 1 plate.

176 For an account of the life-cycle of Eimeria stiedæ consult Wasielewski, Th. von (1904), “Studien und Photogramme zur Kenntnis der pathogenen Protozoen,” Heft. 1 (Coccidia), 118 pp., 7 plates, Leipzig: J. A. Barth. Also, Metzner, R. (1903), Arch. f. Protistenk., ii, p. 13.

177 Gubler, A., “Tumeurs du foie déterm. par des œufs d’helm. . . .” Mem. Soc. Biol., Paris, 1858, v, 2; and Gaz. med. de Paris, 1858, p. 657; Leuckart, R., Die menschl. Paras., 1863, 1st edition, i, pp. 49, 740.

178 Leuckart, R., Die menschl. Paras., 1863, 1st edition, i, p. 740.

179 Leuckart, R., Die Paras. d. mensch., 1879, 2nd edition, p. 281.

180 Leuckart, R., ibid., p. 282.

181 Silcock, “A Case of Parasit. by Psorospermia,” Trans. Path. Soc., London, 1890, xli, p. 320.

182 Pianese has confirmed the fact that Coccidia actually occur in the blood of the hepatic veins of infected rabbits.

183 Die ei- u. kugelf. Psorosp. d. Wirbelt., 1870, p. 16.

184 Railliet and Lucet, “Obs. s. quelq. Cocc. intest.,” C. R. Soc. Biol., Paris, 1890, p. 660; Railliet, Trait. Zool. med. et agric., 2e éd., 1895, p. 140.

185 Arch. f. path. An., xviii, 1860, p. 523.

186 Podwyssotzki, “Ueb. d. Bedeut. d. Coccid. in d. Path. Leber des Menschen,” Centralbl. f. Bakt., vi, 1889, p. 41.

187 Thomas, J., “Case of Bone Formation in the Human Brain, due to the Presence of Coccidium oviforme,” Journal Boston Soc. Med. Sc., iii, 1899, p. 167; Centralbl. f. Bakt. [I] xxviii, 1900, p. 882.

188 “Notes on Paras.,” No. II, Journ. of Comp. Med. and Vet. Sci., 1892, xiii, p. 517.

189 Arch. f. path. An., 1860, xviii, p. 527.

190 Grunow, “Ein Fall von Protozoën (Coccidien?) Erkrankung des Darmes,” Arch. f. exper. Path. und Pharm., 1901, xlv, p. 262.

191 Annals Trop. Med. and Parasitol., iv, p. 255.

192 Centralbl. f. Bakt., Orig., lxxi, p. 66.

193 Bull. Soc. Path. Exot., vii, p. 437.

194 Quinine is still almost exclusively the remedy used in the treatment of malaria. It is prepared from the bark of the cinchona tree. This important remedy was introduced into Europe in 1640 from Ecuador by Juan del Vego, physician of the Countess del Cinchon.

195 The discovery of Laveran is in no way lessened by the fact that one investigator or another (according to Blanchard [Arch. de Paras., vii, 1903, p. 152], P. F. H. Klencke in 1843) had seen, mentioned and depicted malarial parasites. (Neue phys. Abhandl. auf. selbständ. Beob. gegr., Leipzig, 1843, p. 163, fig. 25). In 1847 Meckel had recognized that the dark colour of the organs in persons dead of malaria was due to pigment. Virchow in 1848 stated that this pigment occurred in blood cells. Kelsch in 1875 recognized the frequency of melaniferous leucocytes in the blood of malarial patients. Beauperthuy (1853) noticed that in Guadeloupe there was no malaria at altitudes where there were no “insectes tipulaires,” and suggested that the disease was inoculated by insects.

196 Grassi, B. (1901), “Die Malaria,” 250 pp., 8 plates. G. Fischer, Jena.

197 It should be remembered that some authors (Laveran, Argutinsky, Panichi, Serra) argue against the intra-globular position of malarial parasites and state that they only adhere outwardly to the red blood corpuscles. These views have recently been revived by Mary Rowley-Lawson, and she states that the malarial parasite is “extracellular throughout its life-cycle and migrates from red corpuscle to red corpuscle destroying each before it abandons it.” (Journ. Exper. Med., 1914, xix, p. 531.)

198 The incubation period, that is, the time between infection and the first attack of fever, is ten to fourteen days; with severe infection fewer days (minimum 5 to 6) are needed.

199 Schizonts ingested about the same time perish in the intestine of the mosquito.

200 If the microgametocytes are sufficiently mature the formation of microgametes occurs in the blood of man as soon as it is taken from the blood-vessel and has been cooled and diluted. Such a stage is called a Polymitus form, and the process has been called “exflagellation.”

201 See Schaudinn, F. (1902), Arb. a. d. kaiserl. Gesundheits., xix, pp. 169–250, 3 plates.

202 The pigment masses (melanin or hæmozoin) are taken up by the leucocytes, particularly the mononuclear ones, and are carried especially to the spleen, and also to the liver and the bone-marrow. From this circumstance arises the well-known pigmentation of the spleen in persons who have suffered from malaria.

203 Bull. Soc. Path. Exot., vii, p. 385.

204 Proc. Roy. Soc., B, lxxxvii, p. 77.

205 Annals Trop. Med. and Parasitol., viii, p. 85.

206 Journ. Exptl. Med., xvi, p. 567.

207 Annals Trop. Med. and Parasitol., vi, p. 449; vii, pp. 153, 509.

208 Trans. Soc. Trop. Med. and Hyg., vi, p. 220.

209 Annals Trop. Med. and Parasitol., vii, p. 621.

210 Arch. Inst. Bact. Camara Pestana, iii, p. 11.

211 Parasitology, v (1912), p. 65.

212 Nuttall and Graham-Smith, Journ. Hyg., vii, p. 232.

213 “Piroplasmosis,” Herter Lectures, Parasitology, vi, p. 302.

214 Sci. Mems. Govt. India, No. 29.

215 Quart. Journ. Microsc. Sci., li, p. 297.

216 Sci. Mems. Govt. India, No. 29.

217 Quart. Journ. Microsc. Sci., 1, p. 493.

218 Parasitology, ii, p. 156.

219 Parasitology, ii, p. 325; iii, p. 117.

220 Zeitschr. f. Infekt. paras. Krankh. u. Hyg. d. Haustiere, viii, p. 406.

221 Bull. Soc. Path. Exot., iii, p. 135.

222 Yellow Fever Bulletin, i, p. 251.

223 C. R. Acad. Sci., Paris, xcv, p. 1168.

224 Annals Trop. Med. and Parasitol., vi, pp. 145–214, 3 pls.

225 C. R. Soc. Biol., lxviii, p. 997.

226 Centralbl. f. Bakt., Orig., xlvii, p. 612; see also xlvii, p. 56; lv, p. 373.

227 Journ. Exptl. Med., xii, p. 19.

228 Sitz. Gesell. naturf. Freunde zu Berlin, p. 377.

229 Proc. Soc. Exper. Biol. and Med., xi, p. 152.

230 Science, xxxvii, p. 498.

231 Proc. Acad. Nat. Sci., Philadelphia, May, 1914, p. 432.

232 Proc. Cambr. Philosoph. Soc., xvii, p. 221.

233 “Ueb. d. hyg. Bdtg. d. Gregarinen,” Dtsche. Ztschr. f. Staatsarzneikunde, 1868, xxvi, p. 326.

234 “Ein Befund von Psorosp. in Herzmusk d. Menschen,” Ztschr. f. Hygiene, 1892, xi, p. 435.

235 Kartulis, “Ueb. pathog. Protoz. b. Menschen,” Ztschr. f. Hyg. u. Inf., 1893, xiii, p. 1. Compare also Braun, M., Die Thier. Par. d. Mensch., 2nd Edit., Wrzbg., 1895, p. 92; Braun, M., “Z. Vork. d. Sarcosp., b. Menschen,” Centralbl. f. Bakt. 1895, xviii, p. 13.

236 “Sur un cas de Tub. Psorosp. ob. chez l’homme,” C. R. Soc. Biol., Paris, 1894 (x), I, p. 201. “Le Parasitisme d. Sarcosp. chez l’homme,” Bibliogr. Anat. 1894, p. 79.

237 Arch. Internal Med., III, p. 183.

238 Quart. Journ. Microsc. Sci., li, p. 81.

239 See Fantham, Brit. Assoc. Reports, 1907, p. 553.

240 Quart. Journ. Microsc. Sci., xlix, p. 521.

241 Journ. Pathol. and Bacteriol., xi, p. 270; and Brit. Med. Journ., Nov. 16, 1907, p. 1402.

242 New York Med. Journ., December 21, 1907, p. 1149.

243 La Ciencia Medica (Buenos Ayres), 1912.

244 Lancet, September 3, 1910, p. 726.

245 It may be stated that numerous peculiarly shaped species live in the stomach of ruminants, others in the colon of horses. Several species are found in the rectum of frogs and toads; others, again, on the surface of the bodies of fishes; and various other species exist in and on the bodies of invertebrate animals.

246 Bronn’s Cl. u. Ordn. d. Thierr., i, Protozoa, Part 3, Infusoria.

247 According to Gourvitch (“Bal. coli. Darmk. d. Menschen,” Russ. Arch. f. Path., klin. med. u. Bact., Petrograd, 1896), the conjugated Balantidia are supposed to fuse with each other and form oval cysts two or three times the size of the free organisms, and to divide into numerous globules within the cystic membrane; the process, however, has hitherto not been confirmed. The supposed Balantidium cysts appeared in two patients who were simultaneously suffering from Dibothriocephalus latus, after the administration of anthelminthics. It therefore seems, according to the description, that in reality these forms were actually abnormally large, possibly swollen, young eggs of the tape-worm mentioned.

248 Centralbl. f. Bakt., Orig., xlvii, p. 351.

249 Philip. Jl. Sc., Sec. B, viii, p. 333.

250 Lehrbuch der Protozoenkunde, 3rd ed., p. 963.

251 For a detailed account of the Chlamydozoa see Prowazek’s Handbuch der Pathogenen Protozoen, Bd. i (1911–12). Leipzig, J. A. Barth.

252 Journ. Exptl. Med., xviii, p. 314.

253 Idem, p. 572.

254 This grouping goes back to the year 1800, and was made by J. G. H. Zeder, a physician and helminthologist of Forchheim, who divided the helminths, which until 1851 were generally regarded as a special class of animals, into the groups of round, hook, sucker, tape and bladder worms, as which they are recognized up to the present time. In 1809, K. A. Rudolphi gave them the names Nematodes, Acanthocephali, Trematodes, Cestodes and Cystici.

255 A sucker or acetabulum (little cup) is a round, cup-shaped muscular organ, the muscles of which are sharply defined from those of the body.

256 Nematobothrium filarina, van Bened., on the branchial chamber of the Tunny.

257 The following conditions represent deviations from this type: (1) In Gasterostomum the oral aperture is situated in the middle of the ventral surface, and occasionally is even nearer to the posterior than to the anterior end. There is no proper oral sucker, but the pharynx is thus termed. (2) A few genera, such as Gasterostomum, Aspidogaster, Diplozoon, etc., have only one intestinal diverticulum, which is undoubtedly to be taken as representing the primitive condition, as it is also often found in the young stages of the Trematoda. (3) The branches of the intestines are curved and united behind (several Tristomidæ and Monostomidæ), while in Polystomum integerrimum (in the bladder of frogs) there are several commissures between the intestinal branches, and in the Schistosomidæ the united intestinal branches proceed as one channel towards the posterior end. (4) The termination of the two intestinal branches is not always on a level; they are therefore of different lengths. (5) When the œsophagus is very long the intestinal branches extend both forward and backward, so that the gut exhibits the form of an H. (6) In the broad and flat species the gut-forks form diverticula mostly externally but also internally; these again may branch (fig. 139). (7) In a few cases (Nematobothrium, Didymozoon) the intestine completely disappears up to the pharynx.

258 The following description relates in the main to the Distomata.

259 The following description relates mainly to the Distomata.

260 The typical position of the genitalia is subject to many deviations, which are of importance in the differentiation of the genera and families. The following are some few of these deviations: (1) The genital pore remains on the ventral surface, but is situated beside or behind the ventral sucker, or it becomes marginal, and is then found in front of or beside the oral sucker, or at a lateral edge, or, finally, in the centre of the posterior border; the ducts also correspondingly alter their direction. (2) The ovary usually lies in front of the testes, not rarely, however, behind them or between them. (3) The three genital glands mostly lie together close in front of, or behind, the centre of the body; they may be moved far back, and may incidentally become separated one from the other. (4) The vitellarium may be single, in which case it then may lie in the central field. (5) A few forms possess but one, others several or numerous testes. Amongst the ectoparasitic trematodes there are also species with but one testis; but they mostly have several. As a rule, their uterus is short, but the oötype well developed. Special canals (vagina), single or double, are used for copulation, not the uterus. The vitelline ducts also communicate with the intestine through the canalis vitello-intestinalis (fig. 123).

261 Monogenea: Trematoda in which the anterior sucker, if present, is double. Development without an intermediate host.

262 [Recent work (e.g., Goldschmidt, Zool. Anzeiger, xxxiv, p. 482) has shown that the older views regarding the formation of the egg must be modified. In certain species, at any rate, the shell material is formed by the yellow droplets of the yolk glands and not by the so-called shell gland (Mehli’s gland) secretion, which is clear and watery. The function of this secretion accordingly still requires explanation; according to Looss it serves as a covering secretion for the egg-shell proper. It appears also that other granules, the yolk granules as distinct from the shell drop granules, are not always used up during the development of the embryo and hence do not function as yolk, so these also when they exist, and frequently they are wanting, must serve some other purpose, possibly that of imbibing water for the use of the embryo.—J. W. W. S.]

263 Holostomata: Prostomata with (in addition to the oral and ventral suckers) a third fixation apparatus, generally on a separate part of the body.

264 [Also known as ciliated embryos.—F. V. T.]

265 [In Fasciola hepatica in the summer months the rediæ give rise to daughter rediæ, which then give rise to cercariæ.—J. W. W. S.]

266 The cercaria is the characteristic larval stage of the Trematodes, and corresponds to a cysticercus or cysticercoid, though there is the important difference that the cercaria has an enteric cavity. According to some observers the enteron is represented by the frontal sucker of some Cestodes, and by the rostellum of the majority of others.

The sporocyst and redia are regarded as intercalated stages, viz., as cercariæ exhibiting pædogenesis, i.e., development of young by a parthenogenetic process from individuals (i.e., cercariæ) not yet adult.

267 Leiper places this species in a new genus Gastrodiscoides. Genus Gastrodiscoides, Leiper, 1913, distinguished from Gastrodiscus by: (1) large genital cone; (2) position of genital orifice; (3) disc without papillæ; (4) testes one behind the other.

268 [There does not seem to be any direct evidence of either rabbits or hares normally being invaded by this fluke.—F. V. T.]

269 [This is not the case in Great Britain; fluky sheep are sent to market, there being no danger to man from eating the flesh.—F. V. T.]

270 As an example, this occurred in Berlin in the case of 19,034 oxen, 15,542 sheep, 1,704 pigs, and 160 calves in the period of 1883–1893; during which time 719,157 oxen, 1,519,003 sheep, 2,258,110 pigs, and 567,964 calves were slaughtered. As a matter of fact, however, the number of infected beasts was really larger.

271 In the English translation of Küchenmeister’s work on Parasitology (London, 1857). The specimen is preserved in the Hunterian Museum, London, and is an adult liver fluke, measuring 18 mm. in length and 7 mm. in breadth.

272 This species from Canis fulvus was for long thought to be the same as that here described as Amphimerus noverca. It probably does not belong to the genus Metorchis.

273 In the genus Tocotrema the common genital duct opens into the ventral sucker.

274 It is noteworthy that in this almost classical case no worms were found in any of the sections. It is further noteworthy that the eggs in the rectum showed great irregularity of form. Eggs with a spine at each end were not uncommon; exceptionally eggs with two polar spines and one lateral.

275 In a case from Madras, recorded by Stephens and Christophers, the eggs were long and spindle-shaped, quite unlike the eggs of Schistosoma hæmatobium.

276 They may remain simple, and are then not separated from the remaining muscles of the scolex; or they project as roundish or elongated structures over the scolex, hollow on their free surface, and often divided into numerous areas by muscular transverse ribs. They may also carry accessory suckers on their surface.

277 The various parts of a hooklet are thus named from the point backwards: (1) blade or prong, (2) guard or ventral or posterior root, (3) handle or dorsal or anterior root.

278 There are, however, tapeworms with only one, others with only two or three testes in each segment.

279 I.e., regarded from the interior or centre of the invagination.

280 Bothridia or “phyllidia” are outgrowths from the scolex. They are concave and extremely mobile. By some authors the term “phyllidium” is used for the outgrowth, and the term “bothridium” is restricted to the muscular cup. Bothria, on the other hand, are grooves more or less wide, the musculature of which is only slightly developed and is not separated off internally from the parenchyma. Acetabula, or suckers in the usual sense, are hemispherical cups, without lips and with musculature separated internally from the parenchyma.

281 Until recently this worm, which was understood to belong to a separate species, was proved on examination by R. Blanchard (“Mai. Par.,” 1896), to be Dibothriocephalus latus. Compare also Galli-Valerio, in Centralbl. f. Bakt., Path. und Infektionskr., 1900 (1), xxvii, p. 308.

282 The genus is by some authors divided into two sub-genera—Hymenolepis, s. str., and Drepanidotænia, Raill.

Drepanidotænia.—Body, broad lanceolate, testes three, female genitalia antiporal beside the testes. Scolex small, with eight hooks. Neck very short, longitudinal muscle bundles very numerous. No accessory sac opening into genital atrium.

Hymenolepis.—Narrow, female genitalia ventral to or between testes.

283 Proc. Zool. Soc., 1911, p. 9.

284 A third cysticercoid resembling this, but without hooks, has also been found.

285 [The larval stage of the Davaineas occurs in slugs (Limax) and snails (Helix).—F. V. T.]

286 The Greeks termed the tapeworms ἕλμινθες πλατεῖαι, more rarely χηρία (= fascia); the Romans called them tænia, tinea, tæniola, later lumbrici, usually with the addition lati, to distinguish them from the Lumbrici teretes (Ascaridæ). The proglottids were called Vermes cucurbitini; the cysticerci χάλαζαι (hailstones), later hydatids. Plater (1602) was the first to differentiate Tænia intestinorum (= Bothriocephalus latus) amongst the Lumbrici lati of man from Tænia longissima (= Tænia solium). The term solium was already used by Arnoldus Villanovanus, who lived about 1300; and, according to him, it signifies “cingulum” (belt, chain), while N. Andry, in 1700, traces this word from “solus,” because the worm occurs always singly in man. Leuckart and Krehl derive the word “solium” from the Syrian “schuschl” (the chain), which in Arabian has become “susl” or “sosl,” and in Latin has become “sol-ium.” What Linnæus described under the term Tænia solium was really Tænia saginata; the latter was first distinguished by Goeze, but was forgotten until Küchenmeister, in 1852, again called attention to the differences.

287 The larvæ which on rare occasions are found in the muscular system of sheep are either strayed specimens of Cysticercus tenuicollis, which normally develop in organs of the abdominal cavity, and appertain to Tænia marginata of the dog, or actually Cysticercus cellulosæ. (Cf. Bongert, in Zeitschr. f. Fleisch- u. Milchhyg., 1899, ix, p. 86.)

288 According to Gerlach only young pigs (up to 6 months old) are capable of infection, and perhaps the failure may have been due to the animals chosen for experiment being of the wrong age.

289 Dressel, for instance, examined eighty-seven persons suffering from cysticercus, and found it seventy-two times in the brain, thirteen times in the muscles; K. Müller, in thirty-six cases, found it twenty-one times in the brain, twelve times in the muscles, three times in the heart; Haugg, in twenty-five cases, found it thirteen times in the brain, six times in the muscles, twice in the skin, etc. According to Graefe, amongst 1,000 ophthalmic cases in Halle and Berlin, there was one with cysticercus in the eye; in Stuttgart there was only one in 4,000, in Paris one in 6,000, and in Copenhagen one in 8,000.

290 The diagnosis as a rule is not difficult; the patients themselves frequently observe the pumpkin seed-like segments in the fæces. But in such cases the diagnosis must still be confirmed. In other cases the discovery of the oncospheres in their embryonal shells (embryophores), which cannot be confounded with the other constituents of the fæces, gives complete certainty, although the differential diagnosis between T. solium and T. saginata is hardly possible from the embryophores; but, if evacuated segments are placed between two slides and lightly pressed, the species is easily recognizable by the shape of the uterus (cf. figs. 239 and 241).

291 Abnormal migrations of this species have also been known. Compare, amongst others, Stieda, A., “Durchbohr. d. Duod. u. d. Pancreas durch eine Tænia,” Centralbl. f. Bakt., Path. und Infektionsk., 1900, xxviii (1), p. 430.

292 In Iceland 28 per cent. of the dogs are infected with this Tænia, in Lyons 7·1 per cent., in Zurich 3·9 per cent., in Berlin 1 per cent., and in Copenhagen 0·4 per cent. In Australia even 40 to 50 per cent. of the dogs are affected. It is, however, a question whether, in addition to Tænia echinococcus, a second analogous form is not involved, as the form from Canis dingo attains a length of 10 to 30 mm.

293 Mosler, F., “Ueb. Mittel z. Bekampfg. endem. vork. Echinococcuskrank.,” Deutsch. med. Zeit., 1889, No. 72.

294 In such cases the toxic effects of the echinococcus fluid usually—if not always—manifest themselves. Such effects are manifested by severe symptoms of poisoning being set up, by urticaria, peritonitis, and ascites, and not infrequently they cause a fatal termination.