626 TRYPANOSOMIASIS 



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 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 chroma- 

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

 cedure recommended by Leishman for studying the parasite in 

 sections (p. 114). 



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 

 macronucleus ; there also occurred rosettes, consisting of from 

 four to twenty individuals attached by their posterior extremities. 

 Oval forms were also observed. It was at first supposed that 

 monkeys could not be inoculated with the trypanosomes from 

 the stomach of the fly, but recently Bruce has succeeded in 

 originating an infection in this w r ay; probably, however, the 

 organism remains alive in only a small proportion of flies biting 

 an infective case. Minchin in this connection has described in the 

 gut of the fly different types of the parasite corresponding with the 

 male, female, and indifferent forms found in other trypanosomes. 

 This was confirmed by Koch and by Klein, who also found in 

 the intestine agglomerations of immature forms which they 

 ascribed to the results of sexual conjugation. The most im- 

 portant fact established by the last observer was, however, that 

 when Gl. palpalis was allowed to bite an animal suffering from 

 nagana it did not become infective for some days. This has 

 been confirmed for Gl. palpalis in the case of monkeys suffering 



