238 INFECTION AND IMMUNITY 



movement. After a period of amoeboid activity of 

 greater or less duration, the body again assumed an 

 oval or spherical form and remained quiescent for a 

 time. While in this form it was easily recognised, 

 as the spherical shape caused the light passing 

 through it to be refracted, and gave the impression 

 of a body having a dark contour and a central 

 vacuole, but when it was flattened out and under- 

 going amoeboid changes in form it was necessary to 

 focus very carefully and to have a good illumination 

 in order to see it. The objective used was a Zeiss's 

 one-twelfth inch homogeneous oil immersion. 



Very properly, skepticism with reference to the 

 causal relation of these bodies to the disease with 

 which they are associated was not removed by the 

 demonstration that they are in fact blood parasites, 

 that they are present in considerable numbers during 

 the febrile paroxysms, and that they disappear during 

 the interval between these paroxysms. These facts, 

 however, give strong support to the inference that 

 they are indeed the cause of the disease. This in- 

 ference is further supported by the evident destruc- 

 tion of red blood corpuscles by the parasite, as 

 shown by the presence of grains of black pigment 

 in the amoeba-like micro-organisms observed in these 

 corpuscles and the accumulation of this insoluble 

 blood pigment in the liver and spleen of those who 



