MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 777 



Although this disease has been more common in the tropics, enough 

 cases are known from the American mainland to indicate an increasing 

 importance. 



DERMATOMYCOSES* 



The molds which cause skin diseases form a small group, with very 

 ill-defined relationships to the commoner forms of fungi. They pro- 

 duce a vegetative mycelium within the tissues of the host with fertile 

 branches \vhich bear conidia but indicate little as to their group rela- 

 tionships among fungi. Certain of these diseases have been carefully 

 studied, mostly from the pathological side, but a very large number of 

 such lesions are recorded without adequate study of the organs involved. 

 Most of these diseases are tropical but considerable numbers of cases 

 have been recognized in temperate America in recent years. A few 

 of these diseases are practically cosmopolitan. 



FIG. 163. Trichophyton lonsurans. (After Hyde, from Adami and Nicholls.} 



BARBER'S ITCH, RINGWORM, HERPES TONSURANS, TRICHOMYCOSIS. 

 The disease due to Trichophyton tonsurans (Fig. 163), Malm, has re- 

 ceived many names in different languages. It attacks man and dom- 

 estic animals, the ox, horse, dog, cat, sheep, hog, probably other animals 



* Prepared by Charles Thorn. 



