42 



pheral blood. Apart from the actual presence of the 

 parasites, one may still derive evidence of malarial 

 infection from 



1. The presence of pigmented leucocytes. 



2. An alteration in the proportion of the leuco- 

 cytes. 



Pigmented Leucocytes. Pigmented leucocytes, 

 even in severe malaria are often very few, and often 

 require for their detection prolonged search in large 

 films. In other cases, however, they are abundant. 

 The presence of very few is quite compatible with a 

 severe malarial infection. For instance, in two cases 

 seen by us, only very few were found in the peripheral 

 blood, but in the spleen, post-mortem, enormous 

 numbers occurred. To detect them it is necessary to 

 make large and good films by the method already 

 described. By following the margins and termination 

 of the film, the majority of leucocytes in the film will 

 have passed beneath the eye, and pigment, if present, 

 is readily seen. 



In the vast majority of cases the pigment will be 

 found in the large mononuclear forms, and only very 

 rarely indeed in the polymorphonuclear forms. As a 

 rule, a pigmented large mononuclear (Fig. 7) is 

 crowded with granules of pigment, the presence of 

 only a few grains, or a single granular clump, is excep- 

 tional. The appearance of the clearly defined 

 yellowish -brown or black pigment granules in the 

 clear protoplasm is so characteristic that no doubt 

 ought to exist. It should be remembered, however, 

 that in dirty films specks of dirt may be over a leuco- 

 cyte, and so resemble pigment. In this case similar 

 specks will be found lying free. The occurrence of 

 malarial pigment free in the blood has never been 

 seen by us. 



