22 



Fig. 172. Developmental cycle of plasmodium vivax, the tertian 

 malarial parasite. Figures i to 17 are magnified 1200 diameters; 18 to 

 27, only 600 diameters: i, Sporozoit; 2, penetration of a sporozoit into a 

 red blood-corpuscle; 3 and 4, schizont developing in the red blood-cor- 

 puscles; 5 and 6, nuclear division of the schizont; 7, free merozoits; 8 

 (following the arrows to the left to 3), merozoits entering red blood-cor- 

 puscles, and multiplying by schizogony 3 to 7 ; after longer continuance 

 of the disease the sexual forms arise; ga to 12 a, macrogametocytes; 9b 



