Dermatodectes equi (Gerlach). 
The second variety of mange is caused by the sarcoptes equi These 
creatures penetrate the skin, raising up a small knotted elevation, with & 
small passage, at the extremity of which the acarus resides. This acarus- 
has a tendency to wander about, and is especially abundant on the sides of 
the neck and withers, from whence it spreads over the surface of the body,, 
excepting those parts covered by long hair. The pimples, if examined, are’ 
found to be hard scabs, situated on a moist basis. As the crusts become 
drier, the skin becomes thickened, wrinkled, and fissured. Mange caused by 
this acarus is rare. The course of the disease is slow, and may even cause" 
death from irritation and exhaustion. Dr. Fleming, F.R.C.V.S., LL.D.,. 
has seen the disease in the Crimea. The sarcoptes do not live in colonies: <— - 
like the foregoing, but lead an independent existence. 
‘The third variety of mange is caused by the symbiotes equi, a creature: 
which lives in colonies and invades the limbs, not burrowing, but merely’ 
