SEBACEOUS GLANDS. 377 



is cast out from the mucous passages, and passes from the intes- 

 tinal tract with the fteces, and from the air-passages as sputum, 

 etc. 



SEBACEOUS GLANDS. 



These belong to the outer skin, and commonly open into the 

 follicles of the hairs, but also appear on the free surface of the lips 

 and prepuce, etc., where no hairs exist. 



The secretion cannot be collected in great quantity in a normal 

 condition, but as far as can be made out; it is composed of neutral 



FIG. 16G. 



Section of Skin showing the roots of three hairs and two large sebaceous 



(d). (Cadiat.) 



fat, soap, and an albuminous body allied to casein, and organic 

 salts and water, about 60 per cent. 



The secretion seems to be made up of the remains of epithelial 

 cells which are thrown off from the inner surface of the glands, 

 while they are undergoing a peculiar kind of fatty degeneration. 

 These cells gradually get quite broken down during their sojourn 

 in the gland alveoli, and the secretion is finally pressed out by 



32 



