430 



Avian Diphtheria and Chicken Pox. 



the disease runs an acute or chronic course. Thus there are 

 several clinical forms of disease to be differentiated. 



In one form, which has always been designated as chicken 

 pox, morbid changes develop in the skin, and in the majority 

 of cases the skin of the head is first affected. On comb, ears 



Fig. 65. Chicken j)ox. Epithelial proliferations on the comb, on the wattles, and in 

 the vicinity of the corners of the month. 



and wattles, in the vicinity of the natural openings and es- 

 pecially on the parts of the body which are slightly covered 

 or totally devoid of feathers there arises at first a fine, bran- 

 like, gray deposit, which is soon followed by little nodules, at 

 first reddish-gray in color and with a mother-of-pearl luster, 



