SKIN. 293 



immediately over the true skin, and is a thin membrane, to which 

 the colour of the body in man is owing. 3. The cuticle or epi- 

 dermis constitutes the outermost membrane, and is that part of 

 the skin which is raised in blisters. In this chapter we shall treat 

 only of the cutis or true skin. The other two membranes will 

 occupy our attention in the two following chapters. 



The cutis or corium is a thick dense membrane composed of 

 fibres interwoven like the texture of a hat. When it is macerat- 

 ed for some hours in water, and agitation and pressure are em- 

 ployed to accelerate the effect, the blood and extraneous matter 

 are separated from it ; but its texture remains unaltered. The 

 fibres, after this maceration and softening, may be seen crossing 

 in various directions so as to enclose spaces. These are of con- 

 siderable size at the inner or attached surface of the membrane, 

 where granules of fat projected into them ; but gradually dimi- 

 nish towards the outer surface. The outer surface is not quite 

 smooth, but studded with a number of minute projections called 

 papilla. Each papilla appears to consist of the soft sentient ex- 

 tremity of a nerve, enclosed within a delicate vascular plexus, 

 possessing in some degree the properties of erectile tissue. 



The cutis possesses elasticity to a certain extent, for after dis- 

 tension it retracts. The probability is that it resembles in its nature 

 the cartilages and serous membranes ; for when boiled a suffi- 

 cient time in water it dissolves, and is converted into gelatin. 

 If we suppose a piece of skin freed from the fat and cellular tis- 

 sue, which adheres to its interior side, and from the hair, epider- 

 mis, and papillae on its outer surface, it will contain, besides the 

 fibrous mass of which it is composed, and the vessels which pass 

 through it, a considerable quantity of liquid common to all the 

 soft parts of the living body. Wienholt made a set of experi- 

 ments to determine the proportion of these different substances, 

 and states them as follows :* 



Cutaneous tissue proper and vessels, . 32-53 

 Albumen, (liquid), ^ . 1-54 



Extractive soluble in alcohol, . 0-83 



Ditto soluble only in water, , 7-60 



Water, . . . 57-50 



100-00 



* Berzelins, Trait^ de Chimie, vii. 298. 



