PROTOZOA IN THE CIRCULATORY SYSTEM 75 



fresh blood preparation (under a co\ er-glass) with a low 

 power dry objective and look for the disturbance among the 

 erythrocytes, which may suggest the presence of the trypan- 

 osome. But absolute identification must be made on 

 stained smears under a high power objective. Others advo- 

 cate centrifugalization of the citrated blood. If lymphatic 

 glands are enlarged, gland-puncture should be examined 

 in stained smears. In the advanced stage of infection and 

 also in cases where an early nervous symptom is present, 

 cerebro-spinal fluid should be drawn out, centrifugalized 

 and the sediments examined in stained smears. If this ex- 

 amination is also negative, some portion of the sediment 

 may be inoculated intra-peritonealh^ into a rat or a monkey, 

 the blood of which will reveal the trypanosomes if periodic 

 examinations are made. 



2. Trypanosoma rhodesiense Stephens and 

 Fantham 1910 



This trypanosome is considered the causative organism 

 of Rhodesian or East African sleeping sickness which is 

 more virulent than Gambian form and runs a course of 

 only a few months. It is confined in its distribution to the 

 southeastern coastal region of Africa. 



Tnjpanosoma rhodesiense (Fig. 18) is indistinguishable 

 from T. gamhiense in human blood smears. But when 

 inoculated into rat, the position of the nucleus shifts in a 

 certain proportion of the individuals (usually less than 

 5^), toward the posterior end, near or behind the blepharo- 

 plast, together with the shortening of body. 



Some investigators maintain that T . rhodesiense is the 

 human strain of T. bntcei (of cattle and game animals), 



