GLANDS OF THE SKIN. 333 



the collection of fat globules in the protoplasm of the cells. 

 The cells lying in the middle of the gland and in the lumen 

 of the duct are most markedly changed. Here almost the 

 entire protoplasm is converted into fat, the small globules of 

 which coalesce to form larger drops. The nuclei of these cells 

 become shrunken and dead ; while the cell itself disintegrates 

 and goes to form a part of the glandular secretion. We see 

 that the death of the cells is necessary for the production of 

 the secretion, which is in part formed in the cells during life. 

 While the cells in the middle of the gland are destroyed to 

 form the sebum, other cells are added by the division and 

 multiplication of the peripheral cells. At the end of the fourth 

 month of foetal life these glands begin as solid outgrowths of 

 the outer root sheath. Those which have no connection with 

 hairs appear as down-growths of the Malpighian layer of the 

 epidermis into the corium. 



Sweat Glands. 



Sweat glands (glandulae sudoriparse) are distributed over 

 the whole surface of the skin, with the exception of the inner 

 surface of the prepuce, the glans penis, and the red border of 

 the lips. They are as a rule simple tubular glands, and only 

 exceptionally are branched (e. g., the axillary and circumanal 

 glands). The name coil gland is applied to them on account 

 of the shape of their lower part. 



In these glands two parts are to be distinguished : the duct, 

 and the lower secreting part, which forms a coil and ends 

 blindly (Fig. 241). The body of the gland is found at the 

 border between the corium and the subcutaneous tissue, or 

 may be situated entirely in the subcutaneous fat. The lumen 

 of the secreting part of the tubules is greater than that of 

 the duct. 



In the duct there are two parts ; one in the corium, and 

 the other in the epidermis. The former is coiled slightly, 

 and possesses true walls ; while the part in the epidermis 

 presents no walls of its own. The duct always enters the 



