26 DISEASES OF RABBITS 



ingress for the male element in fertilization. 

 The extreme length is 40 to 49 microns, width 

 22 to 28 microns. In unfertilized adults the 

 protoplasm fills the shell but when fertilization 

 has taken place the protoplasm collects into a 

 spherical mass in the center of the shell and 

 develops a central nucleus. This constitutes 

 an oocyst which is the last stage of develop- 

 ment in the liver. The oocysts pass into the 

 intestine from the liver and are evacuated with 

 the feces. Under favorable conditions of 

 warmth and moisture, the protoplasm of the 

 oocyst splits up into two and then four sporo- 

 blasts. Each sporoblast then becomes 

 elongated in form and becomes a sporocyst, 

 which subsequently undergoes division to form 

 two sporozoites, the remaining unused small 

 mass of protoplasm being termed the residual 

 body. There are thus developed eight spores 

 or sporozoites, or falciform bodies as they are 

 sometimes termed, from one fertilized adult. 

 The whole process takes about a week, and this 

 knowledge is of practical importance as if the 

 hutches are cleaned out twice weekly, no sporo- 

 zoites can be invested by other individuals and 

 the disease spread. The development of the 

 fertilized oocyst must attain the sporocyst and 

 sporozoite stage outside the body as if ingested 

 before that has taken place, development 

 ceases. If the sporocyst containing the sporo- 



