128 



Some authors describing trypanosoma equiperdum give a very 

 characteristic morphological detail, the posterior end of some 

 specimina being divided. We never saw this in our parasites. 

 As to the dimensions there seems to be but little difference. 



Moreover their dimensions differ in different hosts. 



During a recent stage at the Leyden School of Tropical 

 Medicine, Mr. A. KUYER, dutch colonial medical officer, measured 

 over a hundred specimens of both our strains, following the 

 sheme of Lingard and found the following dimensions: 



Tryp. brucei: length in m. M. without flagellum 12.65; 

 with flagellum 19.43 



Tryp. strain D : length in m. M. without flagellum 14.19; 

 with flagellum 21.20. 



Tryp. lewisi : length in m. M. without flagellum 17.84; 

 with flagellum 23.03. 



The complement-fixation test being a group reaction, is 

 not fit to distinguish between two species. A much better method 

 is the crossed-immunity test. An animal that survives after 

 being infected by a certain species of trypanosomes gains an 

 immunity generally for a certain time. It can however be killed 

 by another species of trypanosoma. 



I had the chance to find a cat that survived an infection 

 with ngana after having been severely ill. When she had com- 

 pletely recovered I infected her with the other strain, after 

 wich she died in ten days. 



Still I dare ^not say that the strains are different it being 

 possible that two strains of trypanosoma brucei from the same 

 source get very different in virulency. 



In consequence I shall speak of ngana and the D strain. These 

 curves (fig. 2) show you the time in wich guinea pigs succumbed 

 to the infection. You see that the virulency was increasing. 



The animals show no symptoms at all in the beginning, though 

 trypanosoma may be seen in the blood after a few days. 



A short time before the fatal end they are getting rest- 

 less and trembling. There is loss of appetite and a pronoun- 

 ced emaciation, the head is swollen. Sometimes short before 

 death the posterior extremities are paralysed. The blood is 

 anaemic, flows from a wound much easier than usually and 

 contains an incredible number of parasites. 



