5o6 Malaria 



on the side of the vacuole that has the thinner protoplasmic outUne. 

 The smallest such rings usually have a diameter equal to about 3^ 

 the diameter of the blood-corpuscle. The tiny ring-form, or, as 

 it might better be called, the "seal-ring form," continues until the 

 schizont becomes half the diameter of the blood-corpuscle, when 

 its protoplasm has begun to increase so rapidly that the vacuole 

 no longer appears to be so conspicuous. The organism also becomes 

 irregular in shape and is actively ameboid, its protoplasm streaming 

 this way and that when examined in fresh blood. At this time it 

 may be noticed that the infected blood-corpuscle is increasing in 

 volume, sometimes becoming twice the normal size, and also be- 

 coming pale in color. It seems also as though the disk shape of 



SS 



Fig. 182. Fig. 183. 



Figs. 182, 183. — Gametocytes of Plasmodium malariae: 85, The macrogametocyte; 

 86, the microgametocyte (KoUe and Wassermann). 



the corpuscle was lost, and it had become swollen into a more spher- 

 ical — sometimes irregular — form. The parasite, which may still 

 show a rehc of its original ring-form, now shows plentifully through- 

 out its protoplasm exceedingly fine granules of yellow-brown pig- 

 ment. When from thirty-six to forty hours old, all trace of the 

 "seal-ring" form disappears, the ameboid action becomes less 

 marked, and the parasites (now three-quarters the size of the enlarged 

 pale and misshapen corpuscles in which they are contained) appear 

 as irregular, ragged, protoplasmic bodies filled with fine pigment 

 granules. In about forty-five hours they completely fill the enlarged 

 corpuscles, and begin to gather their protoplasm into rounded forma- 

 tions in which the pigment is no longer distributed, but occurs in 

 irregular stripes or gathers together into a rounded clump. In a 

 couple of hours the blood-corpuscle has disappeared and the rounded 

 parasite, larger than normal red corpuscles, with a lobulated surface, 

 and with its pigment granules collected to form one or two rounded 

 masses, is seen to have reached the stage of the meroblast. This 

 does not form the rosette or "daisy-head" shown by the quartan 

 parasite, but might better be compared to a mulberry, and even- 



