OH, A TREATISE ON TILE. 93 



CHAPTER V. 



PILE BELONGS TO THE DERMIS. Pile belongs to the dermis and generally will persist 

 in growing upon it. We are assured by one of the most eminent surgeons of this city 

 that he has frequently, in different operations, turned flaps of skin in various cavities, to 

 supply the place of the mucous membrane, and has observed that unless the piliferous 

 bulbs (follicles) have been destroyed by a desquamating inflammation, or subsequently 

 removed by excision, the hair natural to the skin continues to develope itself and some- 

 times becomes a source of considerable irritation. 



On the other hand pile does not belong to the mucous membrane, and will not, generally, 

 grow therein. We have often examined with admiration the minute line of demarcation, 

 on the lips, between the skin of the mucous membrane, the former being covered with 

 hair, while the latter will not produce a single filament. 



But for the production of pile the dermis must be perfect; hence we find that where 

 wounds heal by granulation, the cicatrix being an imperfect skin, no hair will grow upon 

 it. It has been said, however, that where the mucous membrane has been left for a long 

 time exposed, as in descents of the rectum and uterus, that hair will grow upon it.* 



The notion of Oken, (in Elem. of Physiol., p. 394,) that hairs are dried bronchial fila- 

 ments, and that, therefore, they continue to occupy in man those situations only where, 

 in the lower animals, bronchia and tentaculse are found, for example around the mouth, 

 upon the head, in the axillae and around the sexual organs, is chimerical. f 



Some of the lower animals are entirely covered with hair, while others have so few, 

 that they are called naked. Some are covered with a mantle and a few hairs, while others 

 have scales in place of the mantle. All these different coverings might be made use of in 

 their classification. 



WHEN PILE NOT USUALLY FOUND EVEN IN THE DERMIS, ^Haii 1 is not usually found in the 

 superior eye-lids, palm of the hand, the soles of the feet,J nor the dorsal face of the last 

 phalanges of the fingers and of the great toe. 



On the head$ hair is found upon the scalp in the auditory passage upon the eye- 

 brows, (supercilium) along the margin of the eye-lids, (cilium) in the nares on the 



* Tellc est 1'analogics entrc ces deux membranes, que la peaiij soumise au contact prolongs des matierc qui baignent la 

 muqueuse, des larmes par example, prend bientot 1'aspect et les caracteres de la muqueuse, de memo que celle-ci, exposee 

 au frottemont des vetements et a 1'aetion dessechante de 1'air, so transforme bientot en peau. (Un Mil. de fait, p. 513.) 



t The mammalia are composed of, 1, a skeleton; 2, splanchnic cavities, of which there are three; 3, limbs; 4, 

 vessels and nerves. All these are enclosed in an outer envelope, called "the skin." It is to this latter that pile belongs. 



J Goldsmith says that the Hare has hair upon the sole of the foot. (Nat Hist, of Man, v. 2, 137.) 



J Dr. Gross proposes to call the hair of the head "crin," from crinis, hair. The French have conferred this name upon 

 the mane and tail of the pachjdermata. 



