The Human Malarial Parasites 



481 



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 formations 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 eventuates in the formation of from fifteen to twenty- 

 five small, rounded or ovoid, pale, unpigmented bodies, the mero- 



Fig. 184. — Parasite of tertian malarial fever: a, b, c, d, e, f, g, Growing pig- 

 mented parasite in the red blood-corpuscles; h, spores formed by segmentation 

 of the parasite — no rosette is formed, but concentric rings of the cytoplasm divide; 

 i, macrogametocyte; i, microgametocyte with spermatozoits. 



zoits or spores. These become freed from the pigment and at- 

 tached to new red corpuscles, in which they are easily recognized 

 as the "tiny-rings" that begin the schizogonic cycle. The game- 

 tocytes of the tertian parasite,' the "free spheres," as they are some- 

 times called, are large, rounded or slightly ovoid bodies, with a 

 uniformly dull bluish-gray or grayish-green protoplasm, in the in- 

 terior of which there is always a circular or semicircular area periph- 

 erally or centrally situated, and colorless. Except in this area 

 the pigment is distributed throughout the parasite. The larger 

 or macrogametocyte, the female parasite, measures ib to 14 fi in 

 diameter. It has a greenish or grayish-green or almost colorless 

 protoplasm, containing an oval or bean-shaped colorless area al- 

 most half as large as the organism itself. Yellowish-brown pig- 



