IMMUNOLOGY 



845 



(latent) periods, with second and third patent periods representing first 

 and second relapses and crises. 



When this infection was analyzed, it was found that the basic rate 

 of reproduction remains comparatively constant, whenever parasites are 



105-1 



103- 



PIOl- 



[9i 



99- 



r60- 



s40- 



c^ 



W.T^JMonk■ex 119 



Nq of Parasites 

 Teroperature 



0- 



FiGURE 188. The changes in number of Plasmodium brasUianum and the percentage 

 of segmenters during the acute rise and crisis of the infection in Central American monkey 

 119. A natural parasiticidal immunity is operative, as evidenced by the inter- and 

 intrasporulation death of parasites; and as acquired immunity is developed at the crisis, 

 further parasiticidal effects are operative, as evidenced by the tremendous death of 

 parasites. The rate of reproduction is temporarily affected, as evidenced by the irregular 

 percentage of segmenters. Had the animal lived, reproduction would have resumed its 

 normal rate, as ascertained from the study of other monkeys similarly infected. (From 

 W. H. Taliaferro, 1932.) 



demonstrable in the blood, since the schizonts produce between ten and 

 fifteen and a half progeny (merozoites) continuously and produce them 

 every twenty-four hours. (This statement is relatively true, since there 

 is no prolonged inhibition of reproduction. Temporary deviations and 

 fluctuations do occur, however. Thus, Boyd and Allen [1934] and Boyd 

 [1939] found that the number of merozoites produced decreases as the 



