188 



DISEASES OF POULTRY. 



site was discovered in the disease of man by Remak 

 in 1837 and more completely demonstrated by Sclion- 

 lein in 1841. It was discovered as affecting cats by 

 Japquetant in 1847, and on mice by Bennett in 1850; 

 while Gerlach, MuUer and Leisering each published 

 cases of it on poultry in 1858. Saint Cyr described 



the first case of 

 favus on the dog 

 in 1868 and in 

 1869 he discov- 

 ered it on the 

 rabbit. 



S YMPTOMS. — 



Favus is a dis- 

 ease of the skin 

 which in birds 

 generally com- 

 mences upon the 

 comb, or other 

 fleshy parts of 

 the head and 

 gr aduall y extend s 

 to and affects the 

 skin of the body. 

 In rare cases it 



magnified 2()0d?am: teglUS UpOH the 



body before the 

 head is affected. The disease manifests itself by 

 small white or light gray, round or irregular spots, 

 from the size of a pinhead to that of a dime, that ex- 

 tend and increase in number, until nearly all of the 

 skin of the affected part is covered. An examination 

 of these spots shows that a thin scale or crust has 

 formed on the surface of the skin. This crust often 



Fijr. 52. — Sarcopies Icevis-, var. gallina 

 seen on the ventral surface 

 eters. 



