THE SKIN AND ITS FUNCTIONS. 339 



by which the peculiar odorous matter of the axillae is secreted form a 

 nearly complete layer under the cutis, and are like the ordinary sudorifer- 

 ous glands, except in being larger and having very short ducts. 



The peculiar bitter yellow substance secreted by the skin of the exter- 

 nal auditory passage is named cerumen, and the glands themselves ceru- 

 min ous glands; but they do not much diifer in structure from the ordi- 

 nary sudoriferous glands. 



(b) Sebaceous Glands. The sebaceous glands (Fig. 232), like the sudo- 

 riferous glands, are abundantly distributed over most parts of the body. 

 They are most numerous in parts largely supplied with hair, as the scalp 



FIG. 232. Sebaceous gland from human skin. (Klein and Noble Smith.) 



and face, and are thickly distributed about the entrances of the various 

 passages into the body, as the anus, nose, lips, and external ear. They 

 are entirely absent from the palmar surface of the hand and the plantar 

 surfaces of the feet. They are minutely lobulated glands composed of an 

 aggregate of small tubes or sacculi filled with opaque white substances, 

 like soft ointment. Minute capillary vessels overspread them; and their 

 ducts open either on the surface of the skin, close to a hair, or, which is 

 more usual, directly into the follicle of the hair. In the latter case, there 

 are generally two or more glands to each hair (Fig. 228). 



Hair. A hair is produced by a peculiar growth and modification of 

 the epidermis. Externally it is covered by a layer of fine scales closely 

 imbricated, or overlapping like the tiles of a house, but with the free 



