22 Sir D. Bruce and Capts. Hamerton and Bateman. [Sept. 18 r 



These gentlemen deserve the highest possible credit for this most difficult 

 achievement, an achievement which most workers in this subject thought 

 impossible. The amount of work they expended and the splendid intelli- 

 gence and pertinacity with which they pursued their object, refusing to 

 accept defeat, command the admiration of all their co-workers in this branch 

 of biological science. Since then the trypanosomes of birds, frogs, and fish 

 have been cultivated by the same and other workers ; but these successes 

 have only been made possible, as a rule, by the pioneer work of Novy and 

 his assistants. Coming out of their work, mention may also be made of the 

 very interesting and important observation made by Kogers when he grew 

 Leishman's bodies in ordinary citrated blood into trypanosome-like flagellates. 



One of the chief interests attaching to this cultivation of trypanosomes is 

 that it may assist in separating the different species of these organisms. At 

 the present time trypanology is in a state of chaos on account of this difficulty 

 in differentiation. Many diseases of auimals caused by trypanosomes have 

 been reported from all parts of Africa, Arabia, India, the Philippines, 

 Mauritius, etc., and it has often been found impossible to name the species 

 of trypanosoma causing them with any approach to certainty. 



As mentioned above, the usual method of separating the different species 

 is by taking into consideration the morphology, the result of inoculation into 

 animals, the cross-immunisation methods and serum diagnosis of Laveran and 

 Mesnil, the mode by which the disease spreads from the sick to the healthy — 

 by a tsetse fly, a stomoxys, a tabanus, or by contact, as in dourine — by the 

 effect of various drugs, cultivation, etc. ; and, as already stated, the effect the 

 parasite has on animals and the mode of conveyance are probably, for 

 practical purposes, the most important. But to assist in separating the 

 various species, cultivation has been of use in the past, and, as the methods 

 become perfected, will be of still greater use in the future. 



The following description of the cultural characters of Dr. Edington's 

 trypansome exemplifies this, for, by comparing them with the cultural 

 characters of other pathogenic species, a fairly shrewd guess at its classifica- 

 tion may be made by this means alone. For the purpose of this comparison 

 a compilation of the cultural characters of Trypanosoma lewisi, Trypanosoma 

 brucei, and Trypanosoma evansi has been made from the writings of Novy, 

 MacNeal, and Smedley. 



It may be mentioned here that attempts have been made in this laboratory 

 to cultivate these three species. The cultivation of the first was found to be 

 a* comparatively easy matter ; but all attempts, and they were many, to 

 cultivate the last two have, up to the present, failed, although Novy's 

 instructions were carefully followed. 



