UF THE SKIN IN UKNKKAL. 205 



ARTICLE I. 

 OF THE SKIN IN GENERAL. 



291. This membrane, extended over the whole surface of 

 the body, whose figure in many of the inferior animals it deter- 

 mines, and receiving on the contrary the form of man and the 

 other vertebrata, is in fact moulded on the subjacent organs, 

 permitting their more strongly marked projections to be seen. 

 Everywhere continuous to itself, an apparent interruption is 

 only to be found in various places on the median line, called 

 the raphe, and which indicates it to have consisted originally 

 of two separate halves. This raphe is well marked in those 

 places where the two halves unite last, and where anormal 

 divisions are most usually found, as in the upper lip, in the 

 perineum and below the umbilicus. The skin seems perfo- 

 rated, but is not, at the apertures of the digestive canal, and 

 the orifices of the respiratory, urinary and genital organs, 

 places where it is reflected and continues on, changing its 

 character with the internal skin. It is the same at the rneatus 

 auditorius externus, where it sends a cutaneous prolongation 

 to the eyes and the ducts of the mamma?, into which it trans- 

 mits others of a mucous nature. 



292. The skin presents two surfaces. The free surface, 

 which is external and in contact with the atmosphere, pre- 

 sents various objects for consideration: we there see wrinkles 

 or folds more or less deep, some of which depend on the sub- 

 cutaneous muscles situated on the he.ad, neck, and about the 

 anus, where the skin can not accompany their contraction; it 

 is the same with respect to the wrinkles on the scrotum occa- 

 sioned by the contraction of the subjacent tissue; others an- 

 swer to the articulations and are caused by their motions: 

 such are those of the hands, feet, &c. ; others again depend 

 upon emaciation and muscular atrophy, when these phenome- 

 na are rapidly produced and at a sufficiently advanced period 

 of life for the skin to have lost its contractility. The surface 

 of the skin presents, besides, small wrinkles, in the palm of 

 the hand and sole of the foot, that are peculiar to the epider- 



