CHAPTER XVI 



Diseases of the Skin 



Favifs (Baldness or White Comb) 



This disease of the skin attacks poultry as well as man and 

 the domestic mammals. In mammals it is called tinea favosa 

 or favus. 



Diagnosis. — The disease usually appears first as small 

 gray white spots on the comb, 



wattles, eyelids and around " """^-v^ 



the ears, that is, on the un- ,^ ^ ^ ^^iz 



feathered parts of the head. 

 The spots enlarge and run to- 

 gether forming a scaly crust 

 which becomes thicker until in 

 three or four weeks it may be 

 as much as 8 millimeters (^ 

 inch) thick. The scales which 

 make up the crust are often 

 formed in concentric rings, the 

 margins raised and the centers 

 depressed, so that the scale is 

 somewhat cup shaped. When 



the crust is removed the skin y^,-,. :,_>. — Head and neck of a 



appears irritated and in places fo^l affected with generalized 



. , „ . , , favus. (After Pearson.) 



the surface is somewhat raw. 



The disease spreads to the feathered parts of the head, the 



neck and the region around the vent. The base of the 



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