106 



THE MECHANICAL FUNCTIONS. 



employed in its construction, in an imaginary sec- 

 tion of the root, on a magnified scale. Every hair 

 takes its rise from a minute vascular pulp, (f,) of 

 an oval shape, which is implanted below the corium, 

 or true skin (d).* This pidp is invested by a sheath 



or capsule (c), which, 

 together with the con- 

 tained pulp, and the 

 root of the hair that 

 grows from it, composes 

 the hulb of the hair. 

 The bulb itself is con- 

 tained in a small cell 

 formed by condensed 

 membranes (s), to which 

 it has no attachment 

 excepting at the lower 

 part (v), where the vessels and nerves of the pulp 

 are passing into it. The hair, growing by depo- 

 sitions from the inside of the capsule which forms 

 the outer part (o), of the shaft, and from the out- 

 side of the pulp, which forms its inner or central 

 part (i), is forced upwards till it has pierced the 

 skin : in the course of its passage a canal is formed 

 for it in the skin itself, continuous with that which 

 encloses the bulb ; and the course of this canal is 

 generally oblique. In the Elephant, where the 

 thickness and density of the hide present consider- 

 able obstacles to the passage of the hairs through 

 it, we may discover, on minute examination, many 

 hairs which have only penetrated a certain way, 



* In the above figure, e is a section of the epidermis, or cuticle ; 

 the dotted part, r, represents the situation of the subjacent corpus 

 nmcosum, and d, the derm, or corium. 



