3^7 



T. lewisii, but subcutaneous is almost equally 

 certain, and in T. hrucei scratch inoculations 

 nearly always succeed. 



Blood Examination. — If present in fair quan- 

 tity there is no difficulty in detecting them fresh 

 with a low power. If very scanty, it may be 

 necessary to centrifugalize the blood. The most 

 delicate test of a successful infection which may 

 have resulted, even though no parasites be found, 

 is a subinoculation into a highly susceptible 

 animal. 



Fig. 82. T. soleae, T. avium (after Danilewsky) 

 Tp. borreli [after Laveran) 



Where parasites cannot be found by an 

 ordinary examination in the blood, they may, 

 however, be readily discovered in the oedematous 

 swellings so often found in trypanosomiasis. 

 Thus it is often extremely difficult, if not im- 

 possible, to detect trypanosomes in the blood of 

 a rabbit infected with T. Brucei, yet they are 

 easily found in the oedematous fluid about the 

 ears, muzzle, etc. 



Cultivation of trypanosomes. — Novy and McNeal have 

 succeeded in growing trypanosomes in vitro. Of those yet tried 

 T. lewisi is the most readily cultivated. The medium consists 

 of a mixture of nutrient agar and defibrinated blood. The pro- 

 portion of blood to agar is 2 : i, though T. lewisi will also grow 



