430 OF THE CUTICLE. 



coverings of the papillae, and which are thus secreted and 

 moulded around these organs. 



The whole of the corneous tissue of the skin, (included 

 usually under the terms of rete mucosum and epidermis,) is 

 formed according to these anatomists of the mingled products 

 of these mucous and coloring glands.* 



The Cuticula or Epidermis, 



has been examined with the greatest care by several of the 

 most successful anatomists ; but notwithstanding their labors, 

 the structure of this substance is by no means understood. 



It appears to have some resemblance to the matter of the 

 nails, and of horn : but is rather more flexible, even after 

 allowing for the difference in thickness. 



In those parts where it is thinnest it is semitransparent. 



It is insensible, and no vessels can be seen in it.f 



* In investigating this obscure and difficult part of anatomy, it has been 

 usual with observers to select the skin of the palms of the hands and soles of 

 the feet, as a type of the whole cutaneous system. There is, however, a 

 difference to be observed. In the palms and soles resides pre-eminently the 

 sense of touch. These parts are likewise destitute of hair, and the papillae 

 which are there very numerous and visible to the naked eye. are very sparsely 

 distributed and appear rudimental in other parts of the body. Much of the 

 discrepancy among anatomists in regard to the structure of the skin, appears 

 to be owing to whether they have made their researches mainly upon the palms 

 and soles, or upon the skin of other parts of the body. Chevalier* and Wallace,! 

 have described especially in the skin of the face, arms, and legs, a system of 

 epidermoid glands, seated in the rete mucosum, and so minute that the latter 

 counted one hundred of them in the one-twenty-fourth part of a square inch, 

 and which gave issue to the sweat. These appear to me, to correspond with 

 the diapnogenous apparatus of Breschet, as he represents them in the palms and 

 soles. 



The opinion of Bichat, is therefore erroneous, that the sense of touch is only 

 more perfect in the hands than other portions, in consequence of the shape of 

 the parts, and the facility with which they may be applied round objects, and 

 that the skin of the abdomen substituted for that of the fingers, would have 

 constituted organs of touch. p. 



f In the early part of the last century, an anatomist by the name of St. 

 Andre, exhibited a preparation of the cuticle which appeared to be injected 

 with mercury. Ruysh declared the thing impossible, and invited him to an 

 investigation of the subject. This invitation was not accepted, and the affair 

 has been generally considered as a mistake or an imposition. H. 



* Lectures on the general structure of the human body, and on the anatomy and functions 

 of the skin, by J. Chevalier. 



t Lectures on the structure of the skin, by W. Wallace, London Lancet, 1837. 



