SEBACEOUS GLANDS. 339 



cells which immediately form the boundary of the canal in this 

 part being somewhat differently arranged from those of the 

 adjacent cuticle. 



The sudoriparous glands are abundantly distributed over 

 the whole surface of the body ; but are especially numerous, as 

 well as very large, in the skin of the palm of the hand, 

 where, according to Krause, they amount to 2736 in each su- 

 perficial square inch, and according to Mr. Erasmus Wilson, 

 to as many as 3528. They are almost equally abundant and 

 large in the skin of the sole. The glands by which the pecu- 

 liar odorous matter of the axillae is secreted form a nearly 

 complete layer under the cutis, and are like the ordinary su- 

 doriparous glands, except in being larger and having very 

 short ducts. In the neck and back, where they are least 

 numerous, the glands amount to 417 on the square inch 

 (Krause). Their total number Krause estimates at 2,381,248 ; 

 and, supposing the orifice of each gland to present a surface 

 of s'gth of a line in diameter (and regarding a line as equal 

 to T ! fl th of an inch), he reckons that the whole of the glands 

 would present an evaporating surface of about eight square 

 inches. 1 



Sebaceous Glands. Besides the perspiration, the skin se- 

 cretes a peculiar fatty matter, and for this purpose is provided 

 with another set of special organs, termed sebaceous glands 

 (Fig. 115), which, like the sudoriparous glands, are abun- 

 dantly distributed over most parts of the body. They are 

 most numerous in parts largely supplied with hair, as the 

 scalp 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 hands and the plantar surfaces of the feet. 

 They are minutely lobulated glands, composed of an aggregate 

 of small vesicles or sacculi filled with opaque white substances, 

 like soft ointment. Minute capillary vessels overspread them ; 

 and their ducts, which have a bearded appearance, as if formed 

 of rows of shells, 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 glands 

 to each hair (Fig. 115). 



1 The peculiar bitter yellow substance secreted by the skin of the 

 external auditory passage is named cerumen, and the glands them- 

 selves ceruminous glands ; but they do not much differ in structure 

 from the ordinary sudoriparous glands. 



