PROTOZOA IN THE CIRCULATORY SYSTEM 87 



(Fig. 22, 1) which is about one-fourth to one-third the 

 diameter of the ervthrocyte. Tlie unevenly narrow periph- 

 eral portion is stained blue and encloses a clear vacuole. 

 A small compact nucleus is stained dark red and appears 





.J\^. 





-^ 



Vf 



9 10 II 12 



Fig. 22. Plasmodium vivax. X 1150. (original) 



1. A young ring fonn. 



2, 3. Growing schizonts. 



4. Two schizonts in an erythrocyte. 



5, 6. Large schizonts. 

 7-9. Schizogonic stages. 



10. Fully formed merozoites. 



11. A macrogametocyte. 



12. A microgametocyte. 



prominently. The infected erythrocvte at this stage does 

 not differ appreciably from uninfected cells, measuring 

 about 7.5|j in diameter. 



2. Growth period. In about six hours the ring-form has 

 now become larger and often assumes irregular amoeboid 



