98 



vascularity is fouud to extend to the capillar surface, and the removal 

 of the hair is followed by bleeding, precisely as if a portion of epidermis 

 had been removed. 



The next layer on the capillar surface of the follicle is one which is 

 continuous \^'ith the rete mucosum of the skin. It dips down to the 

 bottom in a stiutum of vaiying thickness, and forms there an ample 

 nidus for the formation of the bulb. It is remarkably soft, and its 

 structure is detected with difficulty. On the application of a low power 

 it seems granular, but when a one-eighth inch object glass is used, it may 

 be seen to be composed of round nucleated cells. 



A portion of this is invariably removed when a hair is forcibly torn 

 from the skin. 



Hassall describes this as the outer sheath, but does not advert to its 

 continuity with the middle layer of the skin. 



At the base of the hair it is often seen to form a cone, on which the 

 fibrous part of the bulb rests. It is from this cone that the medulla of 

 the hair is produced. The medulla therefore may be said to represent 

 the rete mucosum. 



The innermost layer is connected with the epidermis, and may be 

 most satisfactorily examined when it has been artificially separated from 

 the rest of the contents of the follicle. 



This is most readily effected by macerating a thin section of the haiiy 

 scalp in a moderately strong solution of potash, by means of a little 

 manipulation. The hair and its investing sheath may be removed entire, 

 and then a removal may occasionally be made of the hair itself, leaving 

 the sheath entire. 



This sheath is found to commence superiorly by a funnel-shaped 

 depression of the epidermis, which may usually be detected by the naked 

 eye. The funnel varies in size in different cases, and is best marked in 

 the young infant and foetus : it terminates by closely investing the hair 

 (when oil glands are present the epidermis dips down into them, gra- 

 dually decreasing in density and tenacity); about half way down the 

 foUicle it suddenly changes its character, and forms a dense and strong 

 sheath. A few faint markings on the exterior of this alone remain to 

 indicate its cellular origin. 



This homy sheath terminates below, by surrounding the upper part of 

 the bulb of the hair, to which it is connected by a layer of epithelium ; 

 it is of a fibrous character, and possesses great tenacity — internally, it is 

 often marked by numerous depressions or pits, which seem to arise from 

 some inequality of contraction in its different parts. I have seen this 

 ver)' distinctly marked in skin which has been presened in spirit, while 



