2 S. B. VINCENT 



the other, which are separated by clear spaces or spaces crossed 

 by connective tissue bridges — fine trabeculae (fig. 1), These 

 cavities lie in a diverticulum of the fibrous, dermal, sheath and 

 constitute the blood sinuses. The upper clear portion is known 

 as the ring sinus (e), the lower as the venous or cavernous sinus (j). 



In the lower part of the follicle may be seen an ingrowth of 

 connective tissue which pushes the epithelial layers back and 

 forms a central core at this place where the blood and lymph 

 vessels can come into intimate contact with the growing portion 

 of the hair. This is the papilla. 



Tn the uppet third of the follicle are the sebaceous glands 

 which arise from the outer root sheath and whose ducts open 

 upon the shaft of the hair. These glands lie above the ring 

 sinus while below it or rather extending into it is an outgrowth 

 from the root sheath named variously as the ringwulst, kissen, 

 bourrelet annular, or pulvinus. 



The foUicle shows in a longitudinal section two distinct enlarge- 

 ments which are known as the superior and inferior swellings 

 and the thickened portion of the root sheath above the sebaceous 

 glands has been called the conical body (6). 



Having looked at the salient features of this organ, we may 

 now examine its structure more in detail. As has been said, the 

 epidermal covering consists of two sheaths, an inner and an outer 

 (fig. 2). The inner sheath corresponds to the stratum corneum 

 of the epidermis and in good sections exhibits three layers of 

 cells known respectively as the cuticle, Huxley's and Henle's 

 layers. The latter, a continuation of the stratum lucidum, is 

 frequently lacking. These cells differ somewhat from the usual 

 epidermal cell layers, the two outer ones being nucleated while 

 the cuticle is imbricated in such a way as to interlock with the 

 plates of the cuticle of the hair shaft. For, as the tip of the 

 invaginating hair column grows downward, an indentation is 

 formed in it by the developing hair papilla "which is just suffi- 

 cient to redirect the growth of the central hair column toward 

 the cutaneous surface" which it reaches through a central canal 

 formed by the degeneration of the central epidermal layer of the 

 original hair column. According to this theory the cuticle of 



