SAECOSPORIDIA 



175 



several inches in length. Microscopic examination shows that 

 these patches are cysts containing thousands of tiny spores, 

 segregated into chambers (Fig. 52A) which correspond to the 

 pansporoblasts of Rhinosporidium. The spores (Fig. 52C), es- 

 caping from the cyst, ultimately develop into new cysts in much 



D 



Fig. 52. Sarcosporidia. A, Sarcocyslis hlanchardi of ox, longitudinal section of 

 infected muscle fiber (m. f.) showing spores (sp.) in chambers of compartments 

 (comp.); 11., nucleus of muscle fiber, x 265. (After von Eecke from Wasilewsky.) 

 B, cross section of sarcocyst from human larynx, probably <S, ienella, X 200. Z), 

 same, longitudinal section. (After Baraban and St. Remy.) C, spore of S. tenella 

 of sheep. (After Laveran and Mesnil.) 



the same way as is the case with the nose parasite. Although 

 the muscle parasites have been known to parasitologists for 

 many years there are portions of the life history which are not 

 yet known. Darling and others have suggested that these pe- 

 culiar protozoans may be " side-tracked varieties of parasites of 

 invertebrate animals." We have no definite knowledge of the 

 normal means of transmission although a number of possible 

 methods are known. It has been found that infections can be 

 spread by cannibalism, and that the faeces of infected mice can 

 infect other mice; it has also been stated that spores occur in 

 the circulating blood, which would mean that blood-sucking ar- 

 thropods may be instrumental in the transfer. Fleshflies may 

 also play a part in dispersing the spores. 



Erdmann has shown that when spores of Sarcosporidia de- 

 velop in the intestine a very powerful toxin, cahed sarcocystin, 

 is discharged and destroys the neighboring epithelial cells of the 

 intestine and thus breaks a way for the young parasite into the 



