562 



DISEASES OF THE SKIN. 



pastern mange; it is clearly distinguished from the preceding by its: 

 localization upon the extremity of the legs. It is most frequently 

 found in the fold of the pastern ; thence it extends to the fetlock, 

 the canon, the knee, or the hock ; in exceptional cases it advances as 

 far as the elbow, the shoulder, neck, leg, and thigh. Its develop- 

 ment is extremely slow ; its generalization takes place only after 

 months. 



At the beginning the only important symptom which attracts 

 attention is the habit which the mangy animal has when at rest of 

 abruptly striking the ground with one of the hind legs, doing this 

 at more or less close intervals for hours, but especially during the 

 night. Some horses kick ; all scratch and bite themselves in the 

 region of the fetlock. If the legs are examined we there find an 

 abundant epithelial desquamation, also partial depilations, and later 

 scabs, sometimes also crevices. The skin is dry, thick, as if tanned ;. 

 according to Gerlach, it may be covered after a certain time with 

 horned papillons proliferations. 



The diagnosis is easy. This mange is distinctly characterized 

 by its seat, by the abundance of epidermic desquamation and the 

 intensity of the pruritus ; this latter symptom distinguishes it from 

 eczematous leg grease {eaux aux jambes). 



It is combated by carbolated or cresolated glycerin applications, 

 by carbolated soap or tar ointment (1 part to 10). It disappears 

 generally in a short time. 



Mégnin (according to Delafond) has described it as an intermit- 

 tent mange ; it appears in winter to disappear in the spring. The 

 symbiotes could, however, remain alive during the warm season ;„ 

 they could find sufficient nourishment in the more abundant 

 cutaneous secretions. In winter, on the contrary, they would be 

 forced to attack the skin itself. 



Schwartz explains the frequency of wounds of the pastern by 

 a permanent irritation which is felt by the animals affected by 

 symbiotic mange. 



h. Sheep Mange. 



PsoROPTic MANGE. Sheep may present three kinds of acariases, 

 like the horse; but the most frequent and the most serious is 

 psoroptic mange. The importance of this trouble, from an agri- 

 cultural standpoint, is established by numerous documents. Sta- 

 tistics establish that, in 1884, 170,000 sheep had been affected in 

 Germany and 80,000 (61 per cent, of the whole number of all 



