LNTK<;01KNT. 



25 



ceous glands (Fig. 14>, HBD}, are in connection with each hair-sac, 



4-1-.^ 1r>f fr>i- oa-r^inrr + r> ml tho VlfllT * 



the latter serving to oil the hair. 



FIG. 14. LONGITUDINAL SECTION THKOUGH A HAIK. (Diagrammatic.) 



>'-, >tratum corneum ; S.U, stratum Malpighii ; Co, derma ; Ap, arreetores pili ; 

 Ft, adipose tissue ; F, outer longitudinal layer, and F 1 , inner transverse layer 

 of dermic coat (both composed of connective-tissue) ; Sch, hair-shaft ; M, 

 medulla ; R, cortex ; 0, cuticle of shaft ; jr,S', U'S 1 , extenial and internal 

 root-sheath, the latter reaches above only as far as the point of entrance of 

 the ducts of the sebaceous glands (HBD} ; HP, hair-papilla, containing vessels ; 

 GH, hyaline layer, which lies between the inner and outer hair-sheaths, ie., 

 between the root-sheath and the follicle (dermic coat). 



As feathers are arranged in definite tracts, so also hairs are 

 disposed more abundantly on some parts of the body than on others. 



1 The arrectores pili have also the function of compressing the glands, though the 

 latter are provided with muscles of their own, the development of which is in inverse 

 proportion to that of the proper hair-muscles. 



