560 TRYPANOSOMIASIS 



Inoculation of other species of animals is not usually so 

 successful, though in nearly every case, e.g. in the gui'nea-pig, a 

 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 centrifuged 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 centri- 

 fugalisation to concentrate the organisms, as they 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 centrif ugalised 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 Button 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 chromatin is difficult, but 

 good preparations are obtained by the procedure recommended 

 by Leishman for studying the parasite in sections (p. 545). 



Greig and Gray have studied the trypanosome in the body 

 of the glossina. They found evidence of its multiplying in the 

 stomach of the insect, and it also was seen to undergo changes 

 not elsewhere observed. These consisted in alterations in the 

 position of the micronucleus, which often became anterior to the 



