THE HAEMOFLACELLATES 



'95 



of Amoeba-\ike parasites in the blood of a trout. In the two or 

 three years following, Remak, Berg, and others recorded the 

 occurrence of Htiematozoa which were undoubtedly Trypanosomes 

 in different fishes. The parasite of frogs was first seen by Gluge 

 (1842), and in July 1843 Mayer described and figured certain 

 corkscrew-like and amoeboid organisms from the blood of the same 

 animal, which he termed variously Amoeba rotatoria and Paramoecium 

 costatmn or loricatum. A few months later (November) Gruby also 

 published (24) an account of this parasite, to which he gave the new 

 generic name of Trypanosoma. The same form was subsequently 

 described and figured by Lankester (30) in 1871, who, unaware of 

 Gruby 's work, called it Undulina ranarum ; this author was the 

 first to indicate the presence of a nucleus in the organism (Fig. 1, B). 

 The well-known parasite of rats was discovered by Lewis, in India, in 

 1878, and was afterwards named Herpetomonas lewisi by Kent. 1 It 

 is to Mitrophanow (1883 to 1884) and Danilewsky (1885 to 1889), 

 however, that we owe the first serious attempts to study the com- 

 parative anatomy of these 

 Haematozoa. The work of 

 the latter researcher in par- 

 ticular is deserving of recog- 

 nition, especially when the 

 primitive state of knowledge 

 in regard to blood-technique 

 in those days is borne in 

 mind. Some of Danilewsky's 

 figures of a Trypanosome of 

 birds are reproduced in Fig. 2. 

 Trypanosomes were first 

 met with in cases of disease 

 by Griffith Evans, who, in 

 1880, found them in the blood 

 of horses suffering from Surra 

 in India. The organisms were 

 thought by him to be Spirilla. 

 Steel rediscovered the same 

 form a few years later and 

 took a similar view of its 

 affinities, naming it Spirochaeta 

 evansi. In 1894 Bruce found the celebrated South African parasite 

 ( T. bnicii) in the blood of cattle and horses laid low with Nagana, 

 or Tsetse-fly disease ; and this worker subsequently demonstrated, 

 in a brilliant manner, the essential part played by the fly in trans- 

 mitting the parasite. Brace's discovery may be said to have 

 inaugurated a rapid increase in the number of known forms, the 



1 This form is now placed in the genus Trypanosoma. 



A-C, different forms of Trypanosoma, sangulnis 

 avium, Danilewsky. D, the same parasite dividing 

 longitudinally . n, nucleus ; u.m, undulating mem- 

 brane ; /, nagellum. (After Danilewsky.) 



