FAVUS. 89 



Dermatomy coses. Most of these vegetable parasites 



are related to the Moulds. Of these there are at 



least three found in animals and birds : one the 



unsightly ' Ringworm/ produced by the fungus 



Trichophyton tonsurans — a disease common to man 



and animals alike, and transmitted from one to the 



other; another, common to birds, the so-called 



1 Favus,' due to Achorion Schonleinii (fig. 23) — this 



Favus is also found in the human being, especially in 



young subjects ; the third produces brown eruptions 



in the superficial layer of the epidermis in man, and 



is known as Microsporon furfur \ 



These are all contagious and unsightly complaints 

 in man, but never fatal. In Fowls, however, the 

 ' Favus ' is often a serious malady. 



V. Dermat03iycoses (Favus, etc.). 



These skin fungi are characterized by their circular 

 manner of growth. They are allied to the < Moulds ' 

 that we see on many decaying substances. It is 

 doubtful, however, whether there is any connection 

 between them. In fact, we have almost sufficient 

 evidence to enable us to state that there is no con- 

 nection, and that the Favus parasite gives rise only 

 to Favus, and the Ringworm to Ringworm. 



Each one of the Dermatophytes is made up of two 

 elements — one a system of tubes, forming the so-called 

 mycelium, the vegetative part of the fungus, the stem 

 and leaf, as it were, of the plant ; and, secondly, 



