288 



THE SKIN 



neck, and a short and narrow duct. Occasional glands are formed liy a 

 single sacculo, but more frequently they are compound, the several sac- 

 cules opening by a single short duct which is lined by flattened cells. 

 In the tarsal glands the secreting saccules are connected with the long 



a 



FIG. 276. SEBACEOUS GLANDS IN THE SCALP OF A CHILD. 



a, hair follicle; b, sebaceous gland; c, hair follicles in oblique section; d, horny 

 layer of the epidermis; e, germinal layer; /, derma; g, blood-vessel. Hematein and 

 eosin. Photo. X 83. 



excretory duct by means of a short intercalary duct. The fatty secretion 

 of the sebaceous glands, sebum, is formed by the direct disintegration 

 of the protoplasm of the glandular epithelium. 



The saccules of the sebaceous glands are invested by a thin connective 

 tissue tunic and a delicate basement membrane. They are embedded in 

 the subcutaneous fat or in the deeper part of the corium near the 

 hair follicle. The glands are so disposed as to be included within a 



