CHAP TE R 1; 
DISEASES OF THE 3 KEN, 
General remarks on the functions of the Skin. Mange. Dermatodectes Equz. 
Sarcoptes Equi. Symbiotes Equi. Ringwerm. Urticaria, or Surfett. 
Hide-bound. Eczema. Cracked Heels. Grease and Grapes. Mallenders 
and Sallenders, Mud Fever. Warts. 
GENERAL REMARKS ON THE FUNCTIONS OF THE S\IN. 
As the diseases of the skin of the horse are very numerous and varied, it is 
our purpose to enter pretty fully into the consideration of their symptoms 
and treatment. Before, however, commencing our description, we may say 
a few words regarding the functions and structural peculiarities of this 
important covering, for these are of interest and are well worthy of a few 
moments careful attention. 
The skin is described as a soft and pliant membrane, which invests the 
whole of the external surface of the body, following its prominences, its 
depressions, and its curves. It serves as an effectual protecting cover, 
_ preventing the penetration of noxious materials, and allowing of the escape 
of effete matter in a gaseous liquid and solid state from the blood. The skin 
also has other important offices, for it acts as a sensitive organ in the 
exercise of touch; while it plays a very important part in keeping the 
temperature of the body constant. This varies in health in the horse from 
100° to ror° F, “Our readers are aware how the blood vessels of the skin 
become contracted in cold weather, and how, on the contrary, in hot 
weather they dilate, when perspiration is excreted in much larger quantity. 
By the evaporation of the sweat passed out, heat is absorbed, and thus the 
bodily temperature does not increase materially on the hottest summer's day. 
Exercise increases the production of heat in the body, but it also increases 
the rapidity of the circulation in the blood vessels, which become dilated, 
and thus the sweat glands of the skin become more active. By the 
perspiration excreted and vaporised on the surface of the body, heat is 
prevented from increasing above the standard in health. The actual 
quantity of water excreted per day by the skin in the shape of watery vapour 
is very large. In the human body it varies from a pint and a half, to two 
pints. Finally, also, the skin acts as an absorbing organ. : 
I 
