252 



ANIMAL PARASITES 



and begin their asexual sporogony in the blood. Each develop- 

 mental cycle causing a febrile paroxysm either every day or alter- 

 nate days, or on every fourth day, etc., depending on the character 

 of the organisms and the number of infections. To prevent 



FIG. 79. Coccidium ho minis, from intestine of rabbit: i, a degenerate epi- 

 thelial cell containing two*coccidia; 2, free coccidium from intestinal contents; 

 3, coccidium with four spores and residual substances; 4, an isolated spore; 5, 

 spore showing the two falciform bodies X 1140. (From Railliet, in Tyson's 

 Practice.) 



spread of malaria, mosquitoes must be prevented from reaching 

 individuals infected with malaria and those not infected. Screens 

 accomplish this best. The larva of the mosquito develops in 

 stagnant water. To prevent the development of these young 

 mosquitoes oil should be poured on the water, thus cutting off 

 the air and means of respiration. 



