THE SKIN. 



571 



C. Langer that the young hair is formed around the old papilla. 

 We know, besides, that at a certain height above the papilla 

 there is a knob-like thickening (Henle), which corresponds to 

 the bulb of the falling hair. The, fact added by me is that the 

 new growth of a hair takes place exclusively within the inner 

 root-sheath. The inner root-sheath, below the bulb of the old 

 hair, which is fringed by the torn epidermal scales, becomes 

 gradually widened. At the bottom of the pouch it turns upon 

 itself and produces the bulb, which is composed of medullary, 

 or indifferent or embryonal, corpuscles. The boundary between 

 the two portions of the inner root-sheath is established by the 

 cuticle, which, below the bulb of the old hair, is composed of 





FIG. 238. DIAGRAM OF THE PROCESS OF SHEDDING OF 

 THE HAIR. 



F, follicle; M, arrector pili muscle; P, papilla of hair; B, bulb of hair; IS, inner root- 

 sheath ; 08, outer root-sheath ; C, cuticle ; B, root; OH, old hair still in connection with (YH) 

 the young hair rowing from the bulb. 



columnar epithelia. The pigment, where there is any, lies 

 exclusively in the central portion of the inner root-sheath, from 

 which arises the future hair. The outer root-sheath takes no 

 part in the new formation of the hair. The smooth muscles 

 of the follicle are evidently concerned in the process, inas- 



