324 SUMMARY OF CURRENT RESEARCHES RELATING TO 



among which may be mentioned, the merozoite or spore ; the tro- 

 phozoite and cytocyst of the asexual cycle ; the micro- and macro- 

 gametocytes, oocyst, and sporozoite of the sexual cycle, in which the 

 microgametocyte is extra-corpuscular, while the macrogametocyte is both 

 extra- and intra-corpuscular. Infection may be induced by the food 

 taken into the animal's digestive tract, as well as by other causes. 

 Schizogony and sporogony occur in the red blood-corpuscles of the same 

 host ; in the asexual cycle, multiplication is effected by segmentation, or 

 sporulation. After many generations of schizogony, the sexes become 

 differentiated into macro- and microgametocytes, and conjugate by some 

 means not yet discovered. The extra-corpuscular macrogametocyte, after 

 fertilisation, penetrates a red blood-corpuscle and becomes encysted ; 

 from the cyst-nucleus arise sporoblasts, which in turn are converted 

 into sporozoites. These rupture the oocyst and escape into the plasma^ 

 .vhere they are ready to invade fresh blood-corpuscles. 



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