THE INTEG UMENTA R Y APPEND A GES. 797 



at a high temperature, as during active exertion ; at other times the perspira- 

 tion is insensible. In this respect, the skin has intimate sympathetic relations 

 with other organs which have somewhat analogous functions, such as the 

 lungs, kidneys, intestines, etc., and when its function is disordered or 

 checked, it induces alterations in the secretions of one or all of these organs. 

 The skin is also the seat of a constant and important respiratory action, as 

 it absorbs oxygen and throws off carbonic acid, and any interruption to this 

 process is injurious.) 



AIITICLE II. APPENDAGES OP THE SKIN. 



The appendages of the skin are hairs and horny productions, dependents 

 of the epidermic layer. 



HAIRS. 



The hairs are the filaments which, collectively, form the external covering 

 of the skins of animals. 



In the Horse, the bristly appendages known as horse-hair should be 

 distinguished from the hair proper; the latter are fine and short, particularly 

 in the regions where the skin is thin, imbricated on each other, and spread 

 over the entire surface of the body in a continuous layer which is designated 

 the coat ; the former are long and flowing, occupy the summit of the head, 

 where they constitute the forelock, the upper border of the neck, where they 

 form the mane, and cover the caudal appendage with a splendid tuft, the 

 tail. Some of these also form special organs on the free margin of the 

 eyelids, and are termed eyelashes ; while others inserted about the lips and 

 below the eyes, are named tentacula. (The eyelashes are chiefly implanted 

 in the upper lid. The hairs of the tail are the longest and strongest in the 

 body. These particular hairs also grow on the posterior aspect of the 

 limbs, generally from about the knees and hocks to the hoofs; at the 

 sesamoid bones they constitute a long tuft, the fetlock, which surrounds 

 the horny growth named the " ergot." These " foot-locks " are peculiar to 

 the Horse, and vary in length .and coarseness with the breed of the animal.) 



When the hair is fine, long, and wavy, it forms wool ; and when straight 

 and rigid, as in the Pig, it is known as bristles. 



In the Ass and Mule, the forelock and mane are rudimentary or absent, 

 and the hair of the tail is limited to a small tuft at the extremity of the 

 organ in the former animal, while in the latter it is much less abundant than 

 in the Horse. 



In the Ox, these nairs are not present, except at the extremity of the 

 tail, as with the Ass. 



There are scarcely any other animals which have other hairs than those 

 composing the coat. 



(The ordinary hair of the coat is soft and elastic, inclined in particular 

 directions, and varies in length not only according to the regions of the 

 body on which it grows, but also according to the season or climate. In 

 the Horse, the direction of the hair of the coat gives rise to curiously-formed 

 waves, lines, and circles, the most constant of which is on the forehead. 



In the Cow, the hair is frizzly on the forehead ; on the posterior part of 

 the thighs it has a particular direction, while on the outer side it passes 

 downwards, and from the posterior part of the mammae it ascends as high as 

 the vulva; this characteristic disposition forms what the French have 

 termed ecussons, by which some have pretended to recognise the lactiferous 

 qualities of the animal. 



