574 HEMOSPORIDIA 



The merozoites, which are from 1 to 3 micra and more in diameter, 

 get into the blood plasma and from there infect new erythrocytes. 

 The early differentiation of gametocytes occurs in man, but the 

 completion of this change only takes place after mosquitoes have 

 taken up the parasite with the blood. The gametocytes then become 

 fully developed, form gametes, and these go through a process of 

 maturation in the intestinal tract of anopheles. Microgametes then 

 fertilize the macrogametes, and the copula formed has been called 

 ookinet by Schaudinn. This ookinet penetrates into the submucosa 

 of the gut of the mosquito, and grows considerably in size. After 

 several days its nucleus divides, the cytoplasm likewise segments, 

 and the naked sporozoites are then formed. These circulate in the 

 body of the mosquito, and many of them finally get into the salivary 

 glands and from there into the proboscis of the biting insect, through 

 which they are ultimately discharged into the body of man. Then the 

 asexual cycle starts anew until merozoites are again taken up by 

 anopheles, in which they pass through the sexual part of the 

 cycle. 



Plasmodium Malarise. The parasite causing the quartan type of 

 malaria is like the preceding one first seen as a hyaline body in the red 

 blood corpuscle. It is, however, not as lively motile as the plasmodium 

 vivax. The pigment granules which subsequently form are larger 

 than in the case of the tertiary parasite, and are arranged in a regular 

 peripheral and not in a diffuse manner. The whole parasite remains 

 smaller and the infected red blood corpuscle does not become abnor- 

 mally large, is not very pale, but rather of a dark greenish color. 

 At the end of the third day the Plasmodium malarise is full grown, 

 and is much more highly refractive than the Plasmodium vivax. 

 From eight to twelve merozoites are then formed, arranged in a 

 regular rosette. The merozoites after being set free in the blood plasma 

 invade new corpuscles. The sexual part of the cycle in the mosquito 

 is like that of the preceding variety. When blood containing either 

 the Plasmodium vivax or Plasmodium malarise is obtained by the 

 prick of a needle and allowed to fall on a slide, covered with a cover- 

 glass, protected against evaporation, and watched under the micro- 

 .scope, the formation of flagellated forms can be observed. Fully 

 grown plasmodia filled with very actively motile pigment form wavy, 

 slender prolongations of the protoplasm, several times as long as the 

 diameter of the main body of the parasite. The flagella exhibit a 

 very lively whip-like motion. The cells which have undergone this 

 change are the microgametocytes, which produce the microgametes by 

 the breaking loose of the flagella after they have been provided with 

 nuclear substance from the mother cell which formed them. While 

 the formation of the flagellated organisms occurs, round parasites, 

 with pigment collected in larger masses in a peripheral manner, can 

 be seen. These plasmodia are the macrogametocytes. These sexual 

 forms, which frequently can be seen under the microscope in drawn 



