TEGUMENTAL SYSTEM. 403 



the dock, and upon the pasterns, it is so braced that we can 

 hardly pincli up a portion between the finger and thumb ; but 

 upon the side of the face and neck, upon the ribs, along the 

 flanks, and upon the arms and thighs, it will easily admit of" du- 

 plication. Indeed, between the fore legs we find several natural 

 semicircular doublings of it, in order that the action of the fore 

 extremity may not be constrained ; and along the posterior part 

 of the belly and flanks are other folds, not so numerous, but of 

 larger size, giving freedom of motion to the hind parts : in fact, 

 wherever the panniculus runs, the skin is loose, or that muscle 

 could not have imparted to it the power of corrugation. 



Densittj. — There is considerable variation in the density or 

 thickness of the skin, not only where it covers different parts in 

 the same individual, but in horses of various breeds. What a 

 contrast there is, for instance, between the skin of the cart horse 

 and that of the racer ! And there appears to be, in this respect, 

 some connexion between the cutis and the hair; for the skin, as 

 well as the coat, of a black horse are coarser and thicker than 

 those of a horse of the same breed of another colour ; and it is 

 rather uncommon to see a black racer, whereas the colour is 

 predominant among our large, heavy, cart horses. The skin is 

 thinnest and softest in those parts that are either thinly clad 

 with hair, or are quite hairless : — such are the lips, the nose, the 

 interior of the ears, the borders of the eyelids, the inward part of 

 the thighs, and the generative organs. 



Colour. — The cutis itself is white; its apparent colour it de- 

 rives from the rete mucosum, of which we have evidence in 

 those horses in whom that membrane is also colourless ; such 

 are the milk-white and cream-coloured racers : in pieballs, the 

 skin appears white also in places where the hair is white. But 

 in order to shew that the cutis itself has no connexion in colour 

 with the hair, it will be found that, whether it be taken from a 

 bay, a chestnut, or a black horse, when deprived of its fellow 

 constituents, it will in every instance exhibit the same pale white 

 aspect. 



Structure. — The cutis is of a fibrous texture, tough but supple, 

 elastic, very vascular, and highly sensitive. Its fibres, which 

 take every direction, are so intimately interwoven and knitted 

 together, that it is a texture possessing considerable strength ; a 

 fact we have abundant proofs of both in and out of the body : 

 and that these fibres are elastic is plainly shewn by the skin 

 returning to its former dimensions after having been stretched or 

 wrinkled, and in places where muscular fibre can have no action 

 upon it: in fact, by this proj)erty it is, chiefly, that the skin so 

 nicely adapts itself, both as a partial and general covciiiig, to 



