324 The Diseases of Animals 
found to be most economical. The vats should be fifty 
feet long and so arranged that the temperature can be 
maintained by steam admitted at the bottom. 
The dipping of sheep should be repeated within ten 
days (preferably about a week), iu order to destroy 
mites which hatch after the first dipping. Dipping 
sheep destroys not only the scab mite, but also sheep 
ticks (page 338) and other parasites of the skin. Scabby 
sheep should be carefully fed and cared for, and no 
healthy sheep allowed in evontact with them or on 
ground that has been infested, until the disease has been 
eradicated and the premises disinfected. 
Scab of Cattle 
Cattle scab or itch is caused by a mite (Psoroptes 
communis, var. bovis) very closely resembling the mite of 
sheep scab. It occurs mostly in the great cattle-grow- 
ing regions of the West, where it is known as Texas, 
range, or cattle itch. 
Cattle itch does not cause apparent trouble during 
the grazing season; but when the cattle are on dry feed 
in winter, or when first turned on grass in early spring, 
the trouble exhibits itself, und may cause considerable 
loss. It is usually confined to young cattle, or to those 
out of condition. The first symptom is an intense itch- 
ing of the skin, usually in the region of the neck and 
shoulders. The animals lick themselves, dig at the skin 
with their teeth or horns, rub against posts and other 
objects, sometimes even upon barbed wire, and often 
tearing the skin until it bleeds. 
