236 THE HYPHOMYCETES 



Blood Serum is the only medium on which spores are developed, the 

 most favourable temperature being 30 C. 



Pathogenesis. Artificial infection can only be produced with 

 material containing spores. 



TINEA GALLI (SCHUTZ). 



The chicken favus is due to this fungus, which attacks the comb, 

 wattles, and side of the throat. Round spots appear, which usually 

 become confluent, spreading to the neck, breast, and body. 



Microscopical Appearances. The fungus consists of a mycelium 

 formed of pointed and often branched threads of variable dimensions, 

 which often have small wart-like pedunculate projections, while other 

 joints are club-shaped and sometimes found free, and here and there 

 'fringed with offshoots. In some cases, fine offshoots can be seen on 

 the sides of the mycelium bearing one or two club-shaped grey-coloured 

 bodies. 



Biological Characters. On Gelatine a whitish growth develops ; 

 the gelatine is liquefied, acquiring a reddish colour. 



It also grows on potatoes and bread paste, the best temperature 

 being about 30 C. 



Pathogenesis. The characteristic symptoms are produced in 

 chickens with pure cultures ; while mice, rabbits, and various other 

 experiment animals remain unaffected. According to the conclusions 

 of MM. Constantine and Subrayes, three distinct parasites are the cause 

 of favus in man, the dog, and the fowl. Human favus is nearly related 

 to that of the dog, but distinguished from the latter by its appearance 

 in cultures and by the invariable structure of its mycelium and by its 

 colour. 



TRICHOPHYTON TONSURANS. 



This fungus is found in the epithelial scales in herpes tonsurans. 



Microscopical Appearances. The single mycelial threads are 

 distinctly septate, and from some of them conidia are given off in a 

 similar manner to the Oidium lactis. (For Photomicrograph of this 

 fungus, see Fig. 88.) 



Biological Characters. It grows at room temperature, while 

 the optimum temperature is 30 C. 



On Gelatine Plates. Semi-globular ; white, later yellow, liquefying 

 colonies. 



In Gelatine Stab Cultures, white coating, which floats on the surface 

 when liquefaction occurs. 



