112 THE SECRETIONS. 



Fat. 



The minute sebaceous glands (folliculi sebacei) which are 

 distributed over the whole surface of the body, secrete a peculiar 

 fat, which renders the skin supple and flexible, and hinders it 

 from being permeated by water. The composition of this fat 

 varies in different parts of the body, as is clear from the variety 

 of smell which it evolves in the axilla, on the generative organs, 

 on the scalp, and on the feet of many persons. It is usually 

 of a pale yellow colour, not viscid, and insoluble in water, with 

 which, when it is rubbed, it forms an emulsion. It contains 

 relatively only a small amount of true fat, and is associated 

 with several other animal matters, (as, for instance, albumen 

 and extractive matter,) and a considerable amount of inorganic 

 salts. Esenbeck has made an analysis of the fat collected in an 

 enlarged sebaceous gland. It did not coagulate on boiling, and 

 was precipitated by acids, corrosive sublimate, and tannin. It 

 contained in 100 parts : 



Stearin . . . .24-2 



Extractive matter, with some olein . . 12-6 



Salivary matter . . . .11-6 



Albumen with casein (?) . . . 24-2 



Phosphate of lime . . . 20*0 



Carbonate of lime . . . .2-1 



Carbonate of magnesia . . . T6 



Traces of acetate of soda, chloride of sodium, and loss . 3*7 



