546 



DISEASES OF THE SKIK 



taminated region, the character of which varies according to the 

 degree of intensity of the affection and the constitution of the skin. 



1. In benign cases we observe, in the beginning, spherical or 

 ovoid prominences of the size of a pea, a bean, or a hazel-nut, either 

 isolated or in small groups ; they may occupy a surface of the size 

 of a saucer, but they never exist in large numbers ; on these spots 

 the hair is erect and gathered in tufts ; the skin is sensitive, hot, 

 slightly tumefied. Upon the surface of these circumscribed inflam- 

 matory centres we observe isolated vesicles, which are rarely con- 

 fluent, of the dimensions of a millet-seed to that of a bean, the 

 contents of which, at first watery and limpid, are soon purulent and 

 turbid (pustules). After one or two days they burst, and their con- 

 tents dry, forming thick yellow scabs of the size of a ten-cent piece 

 to that of a twenty-five-cent piece. Within a week the scabs and 

 hairs drop out and uncover circular blotches which are entirely 

 depilated and depigmented, but which are already covered with an 

 absolutely normal epidermis. Exanthema only affects the super- 

 ficial layers of the skin, being arrested at the Malpighian layer ; it 

 heals entirely within two weeks without having produced general 

 troubles. Nevertheless, a moderate induration, gradually becom- 

 ing reabsorbed, is constantly observed on the lymphatic ganglions 

 of the inter-maxillary space and the neighborhood of the pharynx. 



2. This slight form, which is common, is subject to numerous 

 more or less serious aberrations, which depend either on the abun- 

 dance of the infectious elements or on the confluence of the pustules, 

 whether from the want of care of the sick animals, or by frictions 

 of the harness, which irritate and injure the inflamed regions and 

 cause the spread of the bacilli to adjacent parts. 'No matter what 

 the cause may be in all these cases, the exanthema is radiating, the 

 srûall inflammatory islands are multiplied — we may count from 

 fifty to sixty, and the number of pustules may increase four or five- 

 fold. In the neighborhood of the first prominences new phleg- 

 masic centres are developed ; the scabs are enlarged, and — a cir- 

 cumstance particularly aggravating — the inflammation penetrates 

 deeply into the derma, even into the subcutaneous connective tissue; 

 voluminous furunculous pimples are formed, similar to the small 

 tumors produced by the Œstrus larvse, which are very painful 

 and rapidly form abscesses ; in compressing these, purulent masses 

 are forced out of them and more or less deep ulcers remain in their 

 place ; these sometimes become confluent ; later they are filled by 



