DISEASES OF THE SKIN. 345 



round, nucleated, and seldom vary much in size. They are vei-y 

 abundant in the hair follicle. The filaments are articulated, waving, 

 and contain granules. This disease is productive of changes in the 

 root and shaft of the hair, rendering it brittle and easily broken off. 



Synvptorru. — This disease becomes manifest by the formation of 

 circular j^atches on the skin, which soon becomes denuded of hair. 

 The cuticular la^^er of the skin in slightly inflamed, and vesication 

 with exudation occurs, followed by the formation of scaly, brittle 

 crusts. The patches appear silvery gray when incrusted. and are 

 mostly confined to the head and neck. It is a common disease among 

 young cattle in the winter and spring. Very early in the develop- 

 ment of the patches the hairs split, twist, and break off close to the 

 skin. This disease is attended with more or less itching. It is com- 

 municable to man. 



Tinea favosa is due to another fungus, the Achorion schdnleirui. 

 This enters the hair follicle and involves the cuticle surrounding it, 

 small crusts form which increase in diameter and thickness and then 

 become elevated at their margin, forming a cup-shaped scab, the 

 favus cup, which gives the disease its distinctive character. The 

 number of these cups varies from a few to many hundreds. The 

 hairs involved become brittle and broken, fall off M'ith the crusts, 

 leaving small bald patches. The crusts are of a pale or sulphur- 

 yellow color at first; as they grow older they turn darker, or to a 

 brown color. This form of ringNvorm has a peculiar odor, resembling 

 that of mice or musty straw. It is occasionally communicated to 

 cattle by man, mice, cats, etc., all being subject to this disease. 



Treatment. — Remove all crusts by washing with soap and water, 

 then apply acetic acid, sulphur ointment, tincture of iodin or nitrate 

 of jnercury ointment once a day. Cleanse the stable and whitewash 

 it to destroy the spoi*es scattered by the crusts. 



WOUNDS OF THE SKIN. 



SNAKE BITES. 



[See discussion of this subject in chapter on " Poisons and poisoning."] 



VENOMOUS STINGS. 



[See discussion of this subject in chapter on " Poisons and poisoning."] 



BURNS AND SCALDS. 



This is a rare accident among cattle, yet in cases of fire it may 

 occur. The application of heat, whether dry or moist, unless suffi- 

 cient instantly to destroy the life of a part, is always followed by 

 the development of vesicles, or blisters, which contain a thin, watery 



