OF THE CUTICLE. 431 



It extends over the wliole external surHice of the body, 

 except the parts covered by the nails, and is accommodated to 

 the surface of the skin, by forming ridges or furrows, corres- 

 ponding to it. 



It adheres most closely to the cutis ; and when abraded by 

 mechanical violence, the surface of the skin appears moistened 

 by effusion. 



It is not certain that its mode of union with the skin is 

 perfectly understood ; the adhesion of these membranes to 

 each other is as uniform as that of two smooth surfaces glued 

 together, but it is generally said that the cuticle is attached to 

 the cutis by very numerous and fine filaments. 



It has often been asserted that these filaments are the 

 exhaling and absorbing vessels, which pass through the cuticle, 

 to and from the skin. This sentiment appears very reasonable, 

 but no vessels that pass in this way can be injected. 



There are innumerable processes which pass from the cuticle 

 to the skin. IMany of these are tiie linings of the cavities which 

 contain the roots of the hairs ; but they are reported by micro- 

 scopical observers to be like the fingers of a glove, closed at 

 their extremities. 



There are also many processes which contain a sebaceous 

 substance that may be pressed out of them in the form of 

 worms ; these are the ducts of sebaceous glands. 



Besides these, there is an immense number of whitish fila- 

 ments, which are as fine as the most delicate thread of a spider's 

 web. These filaments can be best seen while the cuticle is 

 separating from the skin of the sole of the foot, as suggested by 

 Dr. William Hunter.* They are supposed to be vascular, but 

 they have never been injected. 



When the cuticle is in its natural situation, in union with the 

 skin, there appears to be three species of foramina or pores, on 

 its external surf:ice : viz. 1. Tiiose formed by the passage of 

 the hairs ; and 2. Those which are the orifices of the ducts of 

 the sebaceous glands ; each of which has been already men- 



* See llie London Medical Observations and Inquiries, vol. ii. — n. 



