310 



THE PATHOGENIC RHIZOPODA 



similarly interpret them today. The body ruptures and the spores are 

 liberated, to be carried by the blood into new regions of the skin, where 

 the cytoplasmic cycle is repeated. 



In vaccinia it is apparent that this vegetative cycle is the only phase 

 of the life history, and this, in the same host at least, is limited in 

 extent. In variola, however, the vegetative cycle is repeated many 

 times, but finally the nucleus becomes infected and the parasites, 



Fig. 123 



Cytoryctes variolae in different stages of niuitipiication, outside iarst three figures and 

 outside last two figures of tiie nucleus, (Alter Calkins.) 



-^^stsaitJ^ 



Two of the larger cytoplasmic forms of cytoryctes in the epithelium. The two dark bodies 

 in the middle showing reticular structure are the parasites. XIOOO. 



like nucleophaga, develop in a more definite manner. Chromidial 

 fragments are formed, varying in size and character, while a residual 

 portion of the chromatin, analogous to the residual nucleus of free 

 living rhizopods, remains unformed and apparently useless (Fig. 

 123). The many rings, vacuolated structures, etc., which earlier were 

 interpreted as developmental phases of sporoblast and spores, I now 

 believe to be degeneration forms assumed by the parasite, possibly due 



