OF TJIE HAIRS. 235 



is sometimes developed. Women in general, are less liable to 



become bald than men. 

 The human races, as regards hairs, present differences that 



have been already pointed out. (112 117.) 



Individuals also present numerous ones; some of which re- 

 late to colour, of which there are a great variety of shades; 

 others to their thickness, number and length. Withoff found 

 that on a portion of skin one fourth of an inch square, there 

 were 147 black hairs, 162 chestnut, and 182 auburn. 



Parts highly analogous to hairs, are found in some of the 

 mammalia where they constitute spines; they are horny sheaths, 

 coloured^hard, and pointed, and containing internally, a white 

 spongy substance that has but little solidity; such are the quills 

 of the porcupine. The ordinary hairs seem principally to con- 

 sist of the former substance. 



344. Accidental hairs are found on various parts of the 

 skin and mucous membrane, as well as in cysts. A popular 

 error existed among the ancients respecting the heart, which 

 was said to have been covered with hair, accredited by Plu- 

 tarch and Pliny. Homer, according to some, talks of the hairy 

 heart of Achilles; but it appears that it is of the hairy breast 

 of his hero that he really speaks. As to the other facts, it 

 would appear, according to the remark of Senac, that the whole 

 matter relates to hearts bristled with accidental cellular tissue. 

 The accidental hairs of the skin are those which are found on 

 coloured spots, or on parts of the skin that are thicker than the 

 rest of that membrane; they have been known to acquire con- 

 siderable development on portions of skin previously inflamed. 

 Hairs have often been seen growing from various parts of the 

 mucous membrane ; most generally they have been found in 

 cavities lined by that membrane, or ejected either alone, or as 

 parts of concretions. Although many of these facts are well 

 authenticated, we must not forget, that hairs may be swallowed 

 or otherwise introduced. The hairs of the cysts, either cuta- 

 neous or mucous, are sometimes fixed, and at others free, and 

 in ordinary cases are mixed with fat or sebaceous matter. 

 Those that are fixed in the cysts of the ovary, are in general 

 very evidently placed on the cutaneous parts of those cysts. 



