324 MICROSCOPIC ANATOMY OF THE ORGAS& 



section they are seen to be arranged concentrically. The cells 

 of these layers are without a nucleus in the upper part of the 

 root and shaft; while in the region of the bulb there occur 

 cells which are richer in protoplasm and contain distinct 

 flattened nuclei. 



The root sheaths consist of an outer and an inner layer 

 (Figs. 245 and 246). The inner layer extends from about 

 the upper one-third of the hair root down to the hair papilla. 

 The outer layer, which is a process of the whole epidermis, 

 shows in the upper third of the hair root i. e., up to the 

 orifices of the glands all the layers of the epidermis. Below 

 this it is made up of only that part which represents the Mal- 

 pighian layer. The stratum granulosum extends usually as far 

 down as the openings of the sebaceous glands. 



The inner root sheath consists of three different layers. 

 The innermost layer is the cuticle of the root sheath (cuticula 

 Vaginae pili). It lies immediately on the hair cuticle, and 

 has a structure similar to that of the latter. It is, however, 

 thinner than the cuticle, and consists of exceedingly thin, 

 scale-like cells, which possess nuclei in the lower part of the 

 hair root, but not in the upper. 



Outside the cuticle of the root sheath there lies the sheath 

 of Huxley, which consists of one or two layers of long polyg- 

 onal cells. In the deeper parts of the hair root there are 

 distinct nuclei, while in the upper parts these are entirely absent 

 or only fragmentary. The third and outermost layer of the 

 inner root sheath is the sheath of Henle. This consists 

 of a layer of long flat cells, which in the region of the bulb 

 possess oval nuclei. In the upper parts we find with the 

 progressive cornification only nuclear vestiges. The difference 

 between the cells of the inner root sheath at various places 

 depends on the process of cornification, which increases from 

 below upward. 



The outer root sheath has the character of the stratum germi- 

 nativum of the skin. The cells possess intercellular bridges 

 and a fibrillar protoplasm. 



The connective-tissue hair follicle consists of three layers, 



