SPOROZOA 



769 



of nucleus and cyptoplasm. The pigment of the adult parasite and 

 the unused portion of the cytoplasm are cast off after segmentation 

 as a restkorper, which is promptly phagocyted and such masses ac- 

 cumulate in the spleen, bone marrow and viscera. With rupture of 

 the erythrocyte, at the time of the chill, the merozoites are set free, 

 and if not phagocyted, immediately attack new erythrocytes and the 

 asexual or schizogenous cycle is repeated, until treatment or increas- 

 ing immunity halts or alters the cycle. 



FIG. 188. PLASMODIUM VIVAX. (Army Med. School Collection, Washington, D. C.) 



In practice it is not unusal to find parasites of different ages in 

 the same film, as some individuals seem to develop in advance of 

 others; in this case, however, there will not be much difference in 

 their appearance. When extreme difference of age is noted in films it 

 is probable that there have been several different inoculations, pro- 

 ducing double or triple infections with quotidian or irregular fever 

 curves, and such cases are not uncommon. 



As all the forms so far described belong to the schizogenous cycle, 

 they may be called schizonts, or trophozoites of the schizogenous 

 cycle. The sporogenous cycle begins in man and is completed in the 

 mosquito. The earliest sexual forms noted were the so-called ' * spheres, ' ' 

 large adult parasites, first seen in wet preparations, which did not seg^ 



