220 



ANIMAL PARASITES 



the proper morphology. According to Noguchi there are two types, 

 a slender and a stout, which breed true to these characters and 

 correspond to slight pathogenic variations. Noguchi has succeeded 



FIG. 80. The Spirochaeta refringens is the larger and more darkly stained 

 organism, while the lightly stained and more delicate parasite is the Spirochaeta 

 pallida (Treponema palUduni). From a chancre stained with Wright's blood 

 stain. (Hirsch by Rosenberger.) 



in cultivating the Tr. pall, in pure culture by using the juice from 

 human or monkey's lesions or from the syphilitic orchitis of rabbits. 

 This he grows in serum water or serum agar, to which has been 

 added fresh tissue of rabbit. The organism grows as fine fibrils in 



