SKCT. 61, 62.] HAIRS. TIT 



abruptly into nucleated soft cells, which are broad in the transverse 

 direction of the bulb, very short in the direction of its long axis, but 

 somewhat longer in the direction which is perpendicular or oblique 

 to the long axis of the hair. They are easily acted upon by alkalies 

 and even by acetic acid, possess, without exception, transverse and 

 tolerably long nuclei, and, finally, pass at the end of the bulb into 

 the alrcadv-dcscribcd round cells, of which the latter is formed. 



§ 61. The hair-follicles are flask-shaped sacs, 1 to 3 lines long, 

 which rather closely invest the roots of the hair, and in downy 

 hair are situated in the substance of the upper layers of the corium, 

 in strong or long hair, on the other hand, penetrate, for the most 

 part, into its deeper parts, and even sink more or less deeply into 

 the subcutaneous cellular tissue. They are to be looked upon 

 simply as continuations of the skin with its two constituent parts, 

 the corium and epidermis; and, accordingly, we distinguish in each 

 of them an external, fibrous, vascular portion, the proper hair-sac, 

 and a non- vascular lining, consisting of cells and surrounding the 

 hair — the root-sheath, — which is partly to be regarded as the epi- 

 dermis of the hair-follicle, partly as a special sheath for the root of 

 the hair. 



§ 62. The proper hair-sac, or follicle, consists of two fibrous 

 coats, an external and an internal, and of a structureless mem- 

 brane ; it is, on an average, o*oi5'" to c/022"' in thickness, and 

 possesses at its base a peculiar structure, the papilla of the hair. 

 . The external fibrous coat, the thickest of the three layers of the 

 hair-follicle, determines its external form, and is very intimately 

 connected by its uppermost part with the corium. It consists of 

 ordinary connective tissue with longitudinal fibres, without elastic 

 fibres, but with a good many elongated, spindle-shaped, small cells; 

 it is supplied with a tolerably rich net of capillaries and a few 

 nerve-fibres, with sparing divisions. 



The internal fibrous coat is much more delicate than the ex- 

 ternal; it is bounded by smooth surfaces, is everywhere equally 

 thick, and extends from the base of the hair-follicle only as far as 

 the point of junction of the sebaceous glands. It is, to all appear- 

 ance, destitute of vessels and nerves, and consists of a simple layer 

 of transverse fibres with long slender nuclei, which are particularly 

 easy of observation in the empty hair-follicles of both coarse 

 and fine hairs, with or without the employment of acetic acid. 

 They resemble smooth muscular fibres, but cannot be completely 



