CHEMICAL, QUALITIES OF THE CUTICLE. 435 



a manner which is not well understood, viz. erysipelas, zona, 

 or shingles, pemphigus, and some other eruptions which have 

 no name. In erysipelas there is an obvious inflammation of 

 the skin ; but in some of the other diseases the vesication takes 

 place without the appearance of inflammation. 



5. Vesications often appear when there is a tendency to 

 gangrene. 



6. They also occur in some cases of simple fracture, where 

 there is considerable injury. In these cases the fluid effused is 

 often tinged with blood. 



After death the cuticle is separated from the cutis : 



1. By putrefaction; in which case large vesicles are some- 

 times formed. 



2. By long continued maceration, 



3. By boiling, and 



4. By violent dry heat. 



The cuticle appears to be least deranged when it is separated 

 by putrefaction and maceration : in these cases the internal 

 surface corresponds to the surface of the skin ; and the pro- 

 cesses which contain the hairs, as well as those which are the 

 ducts of the sebaceous glands, are particularly obvious. 



The external surface of the cuticle varies in different places, 

 according to the surface of the skin. In some places it appears 

 scaly at times, and has therefore been supposed to consist 

 entirely of scales ; but in other parts, when examined atten- 

 tively, it appears like a half transparent concreted substance, 

 with a rough surface. 



When the skin has continued dry for a long time, bran-like 

 scales can be rubbed off from it. These are probably com- 

 posed of the residuum of the secretion deposited on the skin, 

 and of a portion of the external surface of the cuticle. The 

 same substance appears upon the first washing of the skin, after 

 that process has been discontinued for any length of time. 



Many speculations have arisen respecting the manner in which 

 the cuticle is originally formed, and reproduced ; but none of 

 these are perfectly satisfactory. 



It is also a question whether the cuticle is endued with vitality, 



