Contagious Pustular Dermatitis in the Horse. Acne. 515 



the Canadian contagious pustular affection. Yet the first authen- 

 tic account dates back to 1 841-2 when Goux found it attacking 

 an entire squadron of the French army in a fortnight. Axe de- 

 scribed it in England in imported Canadian horses in 1877, and 

 Weber observed it in the same year on the continent, where it 

 was attributed to imported English horses. In 1883 it was noted 

 by Schindelka, in 1884, Siedamgrotzky inoculated it from the 

 horse on two rabbits and two Guinea pigs, and to horse and goat. 

 The rodents developed a ' ' malignant oedema ' ' at the point of 

 inoculation and died in six days. Grawitz and Dieckerhoff cul- 

 tivated the bacillus on ox or horse serum and found it 2ju. in 

 length, dividing by segmentation into round or ovoid refractive 

 spores, which may remain connected as diplococci or short chains 

 and which color deeply in fuchsin. It grows most rapidly at a 

 temperature of 37° C, growth ceases at 17° C, and it is destroyed 

 in half an hour at 80° to 90° C. Preserved, dry, it remained 

 virulent for four weeks and produced the characteristic eruption 

 when rubbed on the skin of the horse, ox, dog, sheep or rabbit. 

 It proved fatal to all rodents, including white mice. The microbe 

 is found abundantly in the pus and crusts and is easily shown 

 when these are treated with potash. It produces no putrid 

 fermentation. 



Symptoms. When inoculated it has an incubation of six to 

 fifteen days followed in mild cases by swelling heat and tender- 

 ness of the skin with collection of the hair in erect tufts. Next 

 day there are rounded elevations like peas or hazel nuts, discrete 

 or confluent on the swollen patches. These nodules, at first firm 

 and resistant soon become soft in the center, forming vesicles 

 and finally pustules, which burst in five or six hours and exude 

 an abundant liquid which concretes in a thick amber colored 

 mass. The hairs in the center of the resulting raw surface are 

 easily detached leaving bare spots the size of a dime, with often 

 times a slough attached in the center. When this is finally 

 eliminated the surface gradually cicatrices and recovery may be 

 complete in fifteen days. The skin remains long dappled from 

 the partial discoloration of the epidermis in the seat of th^ pus- 

 tules. The malady is local and hyperthermia is rarely seen. 

 The submaxillary and pharyngeal lymph glands are usually 

 swollen and indurated, but this disappears speedily after the sub- 

 sidence of the eruption. 



