5o8 



Malaria 



cox, R. Blanchard, igoo. Hsemamoeba malarias var. parva, Laveran, 1900. 

 Plasmodium immaculatum, Schaudinn, 1902. Laverania praecox, Nocard et 

 Leclainche, 1903. 



parasite of estivo-autumnal or malignant tertian malarial fever. 

 It is a very small parasite, whose occurrence, even multiple occur- 

 rence, in the corpuscles does not change their size or shape. It 

 does, however, quickly change the appearance of the corpuscles, 

 which become polychromatophilic, and frequently show numerous 

 small dots — the granulations of Schiiffner— in the corpuscular 

 substance. 



The first appearance of the schizont is in the form of tiny rings, 

 which appear to lie upon rather than in the corpuscles, and are first 

 seen at the edges. The rings are outlined by extremely fine lines 



Fig. 185. Fig. 186. 



Figs. i8s, 186. — Gametocytes of Plasmodium vivax: 87, The microgametocyte; 

 88, the macrogametocyte (KoUe and Wassermann). 



and sometimes seem to be incompletely closed, so that they are 

 like horseshoes rather than circles. They increase to several times 

 the original size without losing the ring shape, and are variously 

 known as "middle-sized rings" and "large rings." They are with 

 diflSculty differentiated from the " tiny rings " of the tertian parasite. 

 As the "large ring" stage is reached the parasites begin to disappear 

 from the peripheral blood to complete their growth and undergo 

 meroblast formation in the capillaries of the spleen, the brain, and 

 the bone-marrow. Here the full-grown parasites — meroblasts— 

 appear as irregular disks, resembling those of the quartan parasite, 

 but smaller in size. The pigment is gathered toward the center 

 in a little niass, and eight to twenty-five merozoits are formed in a 

 morula' or mulberry-like mass similar to those of the tertian para- 

 site.* Two or three parasites to the corpuscle are frequent. They 

 are actively ameboid, do not mature simultaneously, and hence 



* Bass asserts that Plasmodium falciparum, like Plasmodium vivax produces 

 32 merozoits. 



