HAIRS AND NAILS 



195 



Pig. 60.— a Hair in its Hair-Sac. 



a, shaft of hair above the skin ; 6, cortical siibstance of the shaft, the 

 medulla not being visible ; c, newest portion of hair growing on the 

 papilla (i) ; d, cuticle of hair ; e, cavity of hair-sac ; /, epidermis (and 

 root-sheaths) of the hair-sac corresponding to that of the integument (»i) ; 

 g, division between dermis and epidermis ; h, dermis of hair-sac corre- 

 sponding to dermis of integument {I) ; k, mouths of sebaceous glands ; 

 n, horny epidermis of integument. 



sole, where their apertures follow the ridges visible on the 

 skin, and amount to between two and three thousand on 



