SPOROZOA 



773 



ways a relatively large purple nucleus. The chromatin of the young 

 rings is usually present as a single dot, but two such dots are frequently 

 seen. In older forms of the tertian and quartan parasites the various 

 changes found in mitosis may be followed in the nucleus. The whole 

 schizogenous cycle may be followed by taking blood smears from a 

 single case of malaria at intervals of three or four hours for forty- 

 eight hours for tertian and aestivo-autumnal, and for seventy-two 

 hours for quartan. 



FIG. 194. PLASMODIUM FALCIPARUM, MALE CRESCENT. (Army Med. School Col- 

 lection, Washington, D. C.) 



Two forms of sporonts or gametes may be seen ; in one the quantity 

 of chromatin is large and the cytoplasm pale blue, while in the other 

 the reverse is found, the nuclear chromatin is comparatively small in 

 quantity and the cytoplasm, being rich in nutrient material, stains 

 deeply. The first form, with abundant chromatin, is the male, or 

 microgametocyte, and the latter the female, or macrogametocyte. The 

 differentiation between schizont and sporont may be made while the 

 parasites are still quite young; since the schizont is characterized by 

 the presence of a nutrient vacuole, and the sporont, of equal age, while 



