Etiology. Symptoms. 



925 



Tlie cultures are distinguished by their slow growth and hy the forma- 

 tion of bright red coloring material. In bouillon-peptone gelatine a 

 white mycelium develops with gradual liquefaction of the medium ; on a 

 decoction of bread, there forms a faintly glistening white mold. 



Constantin & Babrazes consider fowl favus to be a special variety of favus, 

 while according- to Matruchot & Dassonville, Sabonraud, Siiis & Suffran, it has 

 greater similarity to the tricophyton fungus. Tischutkin however proved tliat 

 the fungus changes its character according to its conditions of life just as the ring- 

 worm fungus of sucklings does, consequently he does not consider it to be a special 

 variety. 



Pathogen- 

 icity. If the fun- 

 gus or scales 

 from diseased 

 birds are placed 

 on tlie combs of 

 liealthy fowls, a 

 skin affection is 

 produced wliicli 

 corresponds to 

 the natural dis- 

 ease. The fun- 

 gus does not af- 

 fect the skin of 

 horses, dogs, cat- 

 tle and cats (Fr. 

 Miiller, Gerlach, 

 Schiitz, Scliin- 

 d e 1 k a , Neu- 

 mann), while in 

 mice a favus-Iike 

 eruption and in 

 rabbits and 

 guinea pigs a 

 herpes-like rash 

 has been pro- 

 duced (Constan- 

 tin & Sab razes, 

 Sabouraud, Suis 

 & Suffran), In 

 squamous spots. 



Natural infection occurs through immediate contact and also 

 indirectly. Whether the transmission of the disease by the air 

 is possible, as was assumed by Fr. Miiller, has not yet been 

 proved conclusively. Early age predisposes to the complaint. 



i^i,r.ii 



Fig. 137. Fowl faoiis. ]\Iold-like deposit on the comb and 

 upper part of the neck : thick brown cru^^ts on the comb. 



man the fungus causes broad, erythematous 



Symptoms. Fowl favus begins on tlie comb and on the 

 wattles with small, white spots like mold, which, under the micro- 

 scope, may be recognized as scutula ; they gradually spread and 

 increase in number, and finally coalesce, covering the whole of 



