104 



HAIRS. 



[sect. 55, 56. 



Fig. -15. 



III. — Or the Hairs. 



§55. In every hair we distinguish the free portion, shaft (scapus), 



with its attenuated point, from the part 

 enclosed within the follicle, the root 

 {radix). The former is, in general, 

 straight and cylindrical in straight 

 hair; in curling hair, fiexuous, and 

 somewhat flattened; in frizzly and 

 woolly hair, it is spirally twisted, and 

 quite flat or slightly ribbed. The root 

 is always straight, nearly cylindrical, 

 and, at least in its lower part, softer 

 and thicker than the shaft; in vigorous 

 hairs it terminates in a still softer 

 knob-shaped swelling, from i| to 3 

 times thicker than the shaft — the hair- 

 bulb (bulbus pili), — which is placed like 

 a cap upon a papilliform process of the 

 follicle, the hair-papilla, or, in other 

 terms, receives the latter into an ex- 

 cavation in its base. 



§ 56. Distribution and Si~e of the 

 Hairs. — With regard to size, three va- 

 rieties may be recognised : 1 . long soft 

 hairs, from 1 to 3 feet and more in 

 length, and o - o2'" to o - 05'" in thick- 

 ness : 2. short, stiff, thick hairs, of | to 



Hair and hair-follicle, of middling size ; 

 magnified 60 times, a. Shaft; b. root; 

 c. bulb; d epidermis of the hair; e. 

 inner root-sheath ; /. outer root sheath ; 

 <j. structureless membrane of the hair- 

 follicle; h. transverse and longitudinal 

 fibrous layer of the same ; i papilla of 

 the hair-follicle; k. excretory ducts of 

 two sebaceous glands; /. cutis; m. mu 

 cous; and n. horny layer of the epidermis, 

 the latter entering a certain way into the 

 follicle ; o. end of the inner root-sheath. 



h an 1 



inch 



long, 



and o"03'" to cro7' 



thick; 3. short, extremely fine hairs, 



downy hair (Lanugo),o£ i'" to 6'" long, 

 and o'Oo6'" to o'Oi'" thick. The dis- 

 tribution of the first form is well 

 known ; to the second form belong the 

 hairs at the entrance of the nostrils (vibrissas), and in the external 

 auditory meatus, the eyelashes (cilia) and those of the eyebrows; 

 to the third are to be reckoned the fine hairs on the face, on the 

 trunk and extremities, also those on the caruncula lacrymalis 

 and labia minora, which latter are often wanting. 



The hairs are disposed either singly, or in twos or threes; 

 sometimes, even, in fours and fives. The latter is generally their 



