95 

 CESTODA TAPEWORMS. 



Of the five cestodes mentioned as coming into consideration in the 

 subject under discussion, only one (Hymenolepis diminuta) need be 

 considered seriously. 



CYSTICERCUS CELLULOSE TJENI A SOLITJM. 



[Fig. 20.] 



The larval cestode known as Cysticercus cdlulosx (which causes 

 " measles" in swine) develops (when eaten by man) into a tapeworm 

 which is known as Tsenia solium. This larva is also reported as 

 encysted in the peritoneum of Mus rattus. 



Even if it be granted that the specific determination of the specimen 

 in question as Cysticercus cellulosse is correct, the occasional infection 

 of rats with this parasite would be of very little practical significance 



FIG. 21. Portion of mesentery of rabbit infected with Cysticercus pisiformis. Natural size. (After Railliet, 



1893a, 216, fig. 114.) 



in this country from a public health point of view, as we do not use 

 rats for food for man. Theoretically it is possible to conceive of 

 combinations of circumstances in which such infection in the rat 

 might under certain conditions eventually affect man, but the chances 

 are so remote as to be negligible, especially when compared with the 

 much greater questions which demand attention. 



CYSTICERCUS PISIFORMIS T^NIA PISIFORMIS. 



[Fig. 21.] 



The larval stage of this parasite occurs in rabbits, the adult stage 

 in canines. Parona (1901) reports the occurrence of .the larval stage 

 in Mus brasiliensis, and Vital has recorded the presence of the adult 

 stage in man. 



In view of the fact that Galli-Valerio was unable to infect himself 

 experimentally with this species, the specific determination made by 

 Vital is open to some question. Even assuming that this tapeworm 

 may develop in man, the presence of the larval stage in rats is of 

 such little importance as to be negligible. 



