DISEASES DUE TO PARASITIC FUNGI 



297 



will be found full of the mycelia. The patches are always 

 found to give an acid reaction. 



Favus (Aehorion Schonleinii). 

 Favus was first recognised by Bateman, but it was not 

 until the year 1839 that Schonlein published the fact that 

 the yellow patches were composed of the mycelia and spores 

 of a parasitic fungus. The fungus was first cultivated by 

 Bazin. In its earlier stages it is indistinguishable from 

 the Tinia tonsurans, but soon assumes the honeycomb 

 appearance. It grows on all ordinary media except milk. 



Fig. 24. — Achokion Schonlbinii. (Growth from a favus patch.) 



Gelatine is liquefied. On agar the colonies appear dis- 

 tinctly in forty-eight hours; they are surrounded by a 

 fine fringe of threads. On blood serum star-shaped colonies 

 are formed, which radiate out from the centre, producing a 

 flower-like appearance ; the gelatine is not liquefied. It 

 also grows well on bread and potato. 



Favus affects man, dogs, cats, mice, and rats ; to the two 

 latter animals it is commonly fatal ; the disease is readily 

 transmissible from animals to man. The favus patches are 

 distinguished by their yellow colour, their peculiar smell, 

 and their slightly cup-shaped appearance. 



