202 SENSORIAL FUNCTIONS, 



The cuticle is that thin membrane which is raised by a 

 blister, and which, when removed, leaves the true skin 

 exposed. The pain- consequent upon such exposure, is 

 the best test of the importance of the office which this 

 membrane performs. It is full of minute pores, through 

 which the perspiration escapes. 



The next layer of the skin is the rete mucosum, or 

 mucus web. It is in this that the coloring matter of the 

 different races of men exists. In the African it is black, 

 in the American and European, white, and in American 

 Indians, copper-colored. 



The corium, or true skin lies next. This consists of a 

 tissue of dense fibres, intersecting each other in all direc- 

 tions, the nerves and blood-vessels passing between them. 

 It is a thick and firm covering for the protection of the 

 flesh, and the larger nerves and blood-vessels, some of 

 which are immediately under it. 



631. The composition of the true skin is chiefly gelatine, 

 and hence it is used in the manufacture of glue, and the 

 substance called sizing, used by paper-makers. When 

 this gelatine is hardened by tanning, the skin becomes 

 leather, and is used for shoes and boots. In addition to 

 these, there is the corpus papillarce, which may be con- 

 sidered as a part of the true skin, being formed by the 

 extremities of the nerves and vessels, which have passed 

 through that part. These are little protuberances, and 

 are seen distinctly in the true skin, after the cuticle has 

 been removed by a blister. When the parts are relaxed, 

 they are not so apparent, but become erect, rising a 

 little above the surface, when the skin is stimulated, or 

 touched. 



632. It appears to be in these papillae that the sense of 

 touch resides, these being furnished with nerves appro- 

 priated to this particular sensation. In most cases the 

 ends of the fingers, but sometimes the lips, are employed to 

 convey information by the touch. 



In what part of the skin do the colors of the different races lie ? What 

 is the corium and where is it situated ? Where is the sense of touch 

 situated ? 



