SEBACEOUS SECRETION. 



227 



the hair follicles, and often open into them ; except that on the 

 nymphae and the glans penis, and on the inner surface of the pre- 

 puce, these follicles exist while hairs do not. (Fig. 135.) Yauquelin 

 examined the fat of human hair, and found it oleaginous, colored, 

 and containing sulphur. 



The mineral constituents of these secretions are, a little chloride 

 of sodium and hydrochlorate of ammonia, with phosphate of am- 

 monia and soda. Earthy phosphates are, however, more abundant : 

 the vernix caseosa contains 6.5 per cent, and the smegma prseputii 

 9.7 per cent. 



Of water, the vernix caseosa contains from 66.98 to 77.87 per 

 cent. In the sebaceous secretions after birth it must be constantly 

 varying with the hygrometric and thermometric states of the sur- 

 rounding air. 



The castoreum used as an antispasmodic is merely the smegma 

 from the preputial folds of the penis and the clitoris of the beaver 

 Canadian castor contains 5.8 per cent, of albuminous matter, 8.249 

 of fatty matters, and 41.34 of resinous constituents. (Lehmann.) 



Origin. The sebaceous secretions are secreted by the epithelial 

 cells of the various forms of sebaceous glands. Figs. 135, 136, and 



Fig. 135. 



t\ 



Sebaceous follicles of skin in their relation to the hairs. 



137 show the forms of the simple sebaceous follicles of the skin, 

 and the Meibomian, and the ceruminous glands. 



