406 TEGUMENTAL SYSTEM. 



tiou, having a peculiar odour, and this it is that gives the well- 

 known softness, suppleness, and greasy feel to the part. An 

 unusual flow of this matter, somewhat altered in its nature, is 

 what gives rise to grease. 



Regeneration. — The cutis is but slowly regenerated, appearing 

 to be so at no little expense to the animal economy ; at least 

 Nature never fails to make the old go as far as possible by exten- 

 sion, before the formation of new is commenced : in the cicatri- 

 zation of a large wound, for example, the old skin first contracts 

 from all sides to its utmost, in order to leave as little space as 

 possible to be covered by new. And not only is it with difficulty 

 reproduced, but its living powers are weaker when formed than 

 the old ; for, though it appears to be very vascular at first, its 

 vessels, after a time, either shrink in caliber, or some of tliem 

 become obliterated : hence it is that horses who have once had 

 exulcerated backs from saddle-galls or fistulse are always more 

 disposed to subsequent injury in those places which are com- 

 monly marked with patches of white hair. With regard to the 

 actual formation of cutis, it has been said, that " nothing but 

 skin can produce skin." I am much mistaken, however, if I have 

 not seen, in the human subject as well as in horses, cutis forming 

 upon the granulations, in the very middle of a sore ; which, by 

 fresh depositions upon every side, has met and coalesced with 

 that growing from the old, and thus considerably shortened the 

 term of cicatrization. 



Cuticle. 



The cuticle, epidermis, or scarf-skin, is a thin, tough, inor- 

 ganic membrane, serving as an envelope to the true skin. In the 

 living animal it may be demonstrated by the application of a 

 blister : serum is effused from the exhalents of the cutis, and the 

 cuticle becomes elevated by it into little hemispherical bladders, 

 vesicles or blisters, through the transparent cuticular sides of 

 which the straw colour of the fluid is made perfectly evident. 

 Boiling water will destroy its adhesion to the cutis, both in the 

 living and the dead subject : in the latter they may also be sepa- 

 rated by putrefaction, or by long maceration. 



Composition. — The cuticle appears to be composed of very at- 

 tenuated flexible scales, so disposed as to bear an analogy to the 

 scales of fish, which, in fact, are nothing more than their cuticu- 

 lar coverings : this squamous structure is best seen by viewing 

 through a magnifying glass a piece of cuticle that has been recently 

 peeled off a putrid surface; it is likewise demonstrable in some 

 stages of mange, in which it becomes hard and dry, turns white, 

 and desquamates in successive lauiinte. 



