SUDORIPAROUS OR SWEAT GLANDS. 429 



are separated. Each of these glands consists of a small 

 lobular mass, which appears formed of a coil of tubular 

 gland-duct, surrounded by blood-vessels and embedded in 

 the subcutaneous adipose tissue (fig. 105). From this 

 mass, the duct ascends, for a short distance, in a spiral 

 manner through the deeper part of the cutis, then passing 

 straight, and then sometimes again becoming spiral, it 

 passes through the cuticle and opens by an oblique valve- 

 like aperture. In the parts where the epidermis is thin, 

 the ducts themselves are thinner and more nearly straight 

 in their course (fig. 108). The canal of the duct, which 

 maintains nearly the same diameter throughout, is lined 

 with a layer of epithelium continuous with the epidermis ; 

 and its walls are formed of pellucid membrane continuous 

 with the surface of the cutis. 



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 superficial 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 peculiar odorous matter of the 

 axillae is secreted form a nearly complete layer under the 

 cutis, and are like the ordinary sudoriparous 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 ^th of a 

 line in diameter (and regarding a line as equal to T V^h of 

 an inch), he reckons that the whole of the glands would 

 present an evaporating surface of about eight square 

 inches.* 



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

 external auditory passage is named cerumen, and the glands themselves 



