662 TRYPANOSOMIASIS 



proliferation of the parasite, as indicated by its appearing in the 

 blood, takes place ; but often either no disease occurs or this runs 

 a very chronic course. The relative insusceptibility of animals, 

 especially of the dog, to the Tr. ugandense is taken as evidence 

 that this organism is essentially different from Tr. brucei. 



By means of microscopic examination the organisms may be 

 found in the cerebro-spinal fluid, the blood, or the juice of 

 glands. In the case of the first, about 10 c.c. of the fluid is to 

 be centrifugalised for fifteen minutes and the deposit placed under 

 a cover-glass for examination ; it is better to make a little cell 

 on a slide by painting a ring of ordinary embedding paraffin, 

 to place the droplet of fluid in its centre, and to support the 

 cover-glass on the paraffin; in this way injury to the delicate 

 structure of the organism is avoided. In fresh cerebro-spinal 

 fluid the trypanosomes can be seen to be actively motile ; the 

 number in which they occur varies very much, and the same is 

 true to a greater degree of the blood, in which they are, however, 

 usually very scanty. With regard to the examination of the 

 blood, Bruce and Nabarro state that it is difficult by ordinary 

 centrifugalisation to concentrate the organisms, as these are not 

 readily precipitated. They accordingly recommend that the 

 blood be mixed with citrate of sodium solution (equal parts of 

 blood and of a one per cent, citrate solution) and centrifugalised 

 for ten minutes, that the plasma be removed and centrifugalised 

 afresh for the same time, and that this be repeated three times, 

 the deposit from each centrifugalisation after the first being 

 carefully examined. Greig and Gray have insisted that the 

 examination of the glands in a suspected case forms the most 

 ready means of arriving at a diagnosis, and this opinion has 

 found strong support from the work of Dutton and Todd. The 

 method is to push a hypodermic needle into the gland, suck up 

 a little of the juice, and blow it out on to a slide. In all cases 

 where films of any kind are to be prepared the staining methods 

 of Leishman or Giemsa are to be recommended. Often in 

 cerebro-spinal fluid and gland juice the staining of the chroma- 

 tin is difficult, but good preparations are obtained by the pro- 

 cedure recommended by Leishman for studying the parasite in 

 sections (p. 115). 



Greig and Gray found evidence of the trypanosome multiplying 

 in the stomach of the glossina, and it also was seen to undergo 

 changes not observed elsewhere. These consisted in alterations 

 in the position of the micronucleus, which often became anterior 

 to the macronucleus ; there also occurred rosettes, consisting of 

 from four to twenty individuals attached by their posterior 



