GLANDS. 401 



membrane at the margin of the tarsal cartilages. The fol- 

 licles are usually filled with cells, which may be seen through 

 their walls. These cells present a bright and shining appear- 

 ance from the oily nature of their contents. (See Plate LI II. 



fig- 2.) 



Glands of Hair Follicles. 



The external surfaces of the body, with few exceptions, the 

 palms of the hands and soles of the feet being the principal 

 of them, are covered with the hair follicles, which are placed 

 at tolerably regular distances from each other, and the aper- 

 tures of which are visible even without the aid of glasses. 



The hairs which issue from these follicles differ in character 

 according to their situation ; those of the scalp being long 

 and fine ; those of the beard, &c. short and thick ; while those 

 clothing the general surface of the body are not merely short, 

 but also exceedingly slender. 



In certain situations the hair follicles are frequently with- 

 out hairs, as on many parts of the face ; this, however, is the 

 exception rather than the rule, as very fine hairs are gene- 

 rally present over the entire surface of the face. 



It is into these hair follicles that almost all, if not all, seba- 

 ceous glands open. 



The sebaceous glands of the hair follicles consist of several 

 distinct cells or sacculi, each of which has a separate ex- 

 cretory duct ; two or more of these ducts, there being some- 

 times three, four, or five, open into one common duct, which 

 last opens upon the sides of the hair follicles : there are usually 

 two, but sometimes more of these common ducts, and very 

 frequently several of the primary excretory tubes open directly 

 into the hair follicle. The ducts are large, and usually straight ; 

 but occasionally, like those of the sudoriferous glands, they are 

 slightly spiral. (See Plate LIII. fig. 1. 3.) 



Those sacculi which open into the hair follicles by distinct 

 ducts are to be regarded as separate glands. In the hair 

 follicles of the scalp the glands are usually binary. 



The glands of the hair follicles are not confined to the ex- 



K K 2 



