XXIX.J THE SKIN. 321 



alcohol. V.S. must be made parallel to the course of the hair- 

 follicles, which requires some care. Others are made across the 

 follicles at different levels ; but in this case care must be taken not 

 to make the section parallel to the surface of the skin, but at right 

 angles to the course of the hair-follicle. If an oblique section be 

 cut, the hair-follicles are cut at different levels. 



Harden a small piece of the human scalp (2 cm. square) in 

 Miiller's fluid and afterwards in alcohol. Stain a section in log- 

 wood, or first with logwood and then with picro-carmine. Mount 

 in balsam. 



6. V.S. Hair-Follicle. (a.) (L) and (H) Observe the very thin 

 epidermis, the thick cutis vera, and deep down the subcutaneous 

 masses of fat; the hair- follicles, running obliquely through the 

 skin, each one with a lair in it. At the lower part the hair has a 

 bulbous end implanted on a papilla ; the various coats of the hair- 

 follicle, some continuous with the corium, and others with the 

 epidermis. The following scheme shows the layers of the hair- 

 follicle ; 



Coverings of a Hair- Follicle from Without Inwards. 



., , f (a.) Longitudinally-arranged fibrous tissue. 



1. Fibrous layers . | ^ CircSlarly-arringed sgindle-cells. 



2. Glass-like or hyaline membrane. 



( (a.) Outer root-sheath. ( Henle's layer. 



3. Epitheliallayers < (b.} I Inner root-sheath, -j Huxley's layer. 



( (c.) Cuticle of the hair. ( Cuticle of root-sheath. 



4. The hair. 



(b.) Dermic Coverings. (i.) (a.) The outer fibrous sheath 

 denser than and continuous with the corium. The fibres run for 

 the most part longitudinally, (b.) The inner fibrous sheath of 

 fibrous tissue has a more circular arrangement and is seen as fibres 

 cut across transversely, with a few nuclei interspersed. 



(2.) The hyaline or basement membrane, clear, structureless, and 

 well marked. It separates the dermic from the epidermic coverings 

 of the hair. 



(3.) The Epidermic Coverings. (a.) The outer root-sheath the 

 most obvious part of the covering consisting of several layers of 

 nucleated cubical cells, continuous with and resembling those of the 

 Malpighian layer. 



(b.) The inner root-sheath, much narrower and paler, consisting 

 of three layers of cells of different characters, is present only in the 

 lower part of the follicle, i.e., below the sebaceous gland. 



(4.) The hair with its cuticle. 



(a.) At its lowest part the bulbous enlargement of the hair, with 

 29 X 



