154 HEALTH AND DISEASE 



distinguished from each other liy the hn;ii;er and more compact or Haky con- 

 dition of the epidermis which is formed in the hitter. 



Symptoms. — Generally the skin is harsh, dry, thickened, wrinkled, 

 and dirty, and the hair about the diseased parts stares. Patches are seen 

 here and there consisting of superimposed layers of epidermis, which may 

 be removed in thick flakes or hard, compact, horny layers. Sometimes the 

 epithelial growth assumes the form of a more or less cylindrical outgrowth 

 or horny excrescence which rec|uires to be cut off. Some of these epithelial 

 developments are black and dirty, while others wear a white shiny appearance 

 not unlike mica. 



In the early period of formation they are covered with a bran-like 

 epithelium which desquamates, but later develops into dense Haky patches. 



Ichthyosis is a purely local disease, confined to the skin, and so long as 

 it does not appear on parts to which the harness is applied the patient may 

 suffer but little inconvenience from it. 



It cannot, however, be cured, and when, as sometimes occurs, it seriously 

 attacks these parts, the chafing of the collar or saddle altogether incapaci- 

 tates the animal from work. 



Where it accumulates in large heaps it may be removed by hot water 

 in which a little soda is dissolved, after which the skin round about it may 

 be massaged and the affected part smeared with vaselme. 



HYPERTROPHIES AND ATROPHIES 



HYPERTROPHIES 



Verrucse.^ — Verrucae or Warts are of very common occurrence, and 

 consist in a local enlargement or overgrowth of all the constituents of 

 the skin. The horse is particularly liable to them; they appear in dif- 

 ferent positions, and frec|uently in parts which come in contact with the 

 harness; but they are of still more frequent occurrence in parts of the 

 skin which are absolutely free from all risk of pressure or friction, and 

 this fact suggests that neither of these causes can have much to do 

 with their production. On the eyelids, about the lips, on the inferior 

 parts of the abdomen and the sheath, warts are common, and these parts 

 are free from contact with the harness or pressure of any kind. Warts are 

 of different forms, sometimes being diffused and scarcely raised above the 

 surface, involving large portions of the skin. Another form is the ordinary 

 pedunculated wart, which hangs from a pedicle or narrow neck ; and there is 

 also a lobulated form which projects from the skin and generally presents 

 a red and sometimes bleedins; surface. 



