COCCIDIOSIS S7 



zoites be taken into the body of a rabbit with 

 the food, the envelope is dissolved by the pan- 

 creatic juice and the sporozoites set free. The 

 sporozoites are actively motile and penetrate 

 the epithelial cells of the intestine or bile ducts, 

 entering the protoplasm of the cell and push- 

 ing its nucleus to one side and assuming a 

 spherical shape. This sphere which develops 

 at the expense of the invaded cell is now called 

 a schizont ; it has no enveloping membrane but 

 contains a large alveolus or vacuole. By a 

 process of asexual multiplication, the schizont 

 produces from ten to fifteen nucleated and fal- 

 ciform bodies, which again subdivide into 

 daughter cells, which arrange themselves 

 around the periphery of the mother cell, pre- 

 senting the appearance of the quarters of an 

 orange. The schizont then splits up, and the 

 contents which are now termed merozoites are 

 set free. The merozoites are motile and wan- 

 der free in the intestine ; some perish but others 

 invade fresh cells and repeat the process of 

 schizont formation by which other merozoites 

 are produced. It is this repeated invasion of 

 cells and rapid multiplication of individuals 

 that account for the rapid development of the 

 disease and the lesions produced. 



The above process is termed schizogony. 

 There appears to be a limit to the duration of 

 schizogony, and when this is reached the mero- 



