726 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



Dermatomycoses* 



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

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

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

 branches which bear conidia but indicate Httle as to their group rela- 

 tionships among fungi. Certain of these diseases have been carefully 

 studied, mostly from the pathological side. 



Barber's Itch, Ringworm, Herpes Tonsurans, Trichomycosis. 

 — The disease due to Trichophyton tonsurans (Fig. 152), Malm, has re- 



FiG. 152. — Trichophyton tonsurans. {After Hyde, from Adami and, Nicholls.) 



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

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

 as well. It is characterized by the formation of circular patches from 

 which eventually the hairs fall. These patches enlarge radially and fuse 

 into large areas covered with crusts with more or less discharge in the 

 center. The fungus is recognized microscopically by examination 

 of hairs pulled from the growing edge of the infection. The hyphse 

 penetrate the layers of the skin and especially surround the roots of 

 the hairs which, when first affected, stand stiff and straight. 



• Prepared by Charles Thorn. 



