52 Structure and Classification of Micro-organisms 



tributed among these, then further divided so th^t some of it reaches 

 each sporozoi'te. 



In the process of sporulation the entire parent may be used up, 

 as in Coccidium and- Plasmodium or the parent may continue to live 

 and later form additional sporozoites, as in Sarcocystis. 



Encystment. — Nearly all of the protozoa are capable at times of 

 encysting themselves, i.e., surrounding themselves with dense 

 capsules by which hfe may be preserved for some time amid such 

 unfavorable surroundings as excessive cold, excessive dryness, and 

 absence of food. Sometimes the encysted stage is the spore stage 

 (Coccidium), sometimes it is the adult stage (Ameba). Under these 

 circumstances we find an analogy with the sporulation of the 

 bacteria which is not for purposes of multiplication, but for self- 

 preservation. The encysted protozoa are less hardy, however, than 

 the bacterial and other plant spores, and succumb to comparatively 

 slight elevations of temperature. 



