SEBACEOUS MATTEK. 



329 



Fig. 103. 



glands of the skin are found most abundantly in those parts which 

 are thickly covered with hairs, as well as on the face, the labia 

 nrinora of the female generative organs, the glans penis, and the 

 prepuce. They consist sometimes of a simple follicle, or flask- 

 shaped cavity, opening by a single orifice ; but more frequently of 

 a number of such follicles grouped round a common excretory duct. 

 The duct nearly always opens just at the root of one of the hairs, 

 which is smeared more or less abundantly 

 with its secretion. Each follicle, as in the 

 case of the mucous glandules, is lined 

 with epithelium, and its cavity is filled 

 with the secreted sebaceous matter. 



In the Meibomian glands of the eye- 

 lid (Fig. 103), the follicles are ranged 

 along the sides of an excretory duct, 

 situated just beneath the conjunctiva, on 

 the posterior surface of the tarsus, and 

 opening upon its free edge, a little be- 

 hind the roots of the eyelashes. The 

 ceruminous glands of the external audi- 

 tory meatus, again, have the form of long 

 tubes, which terminate, at the lower part 

 of the integument lining the meatus, in 

 a globular coil, or convolution, covered 

 externally by a network of capillary bloodvessels. 



The sebaceous matter of the skin has the following composition, 

 according to Esenbeck. 1 



MEIBOMIAN 

 Ludovic. 



GLANDS, after 



COMPOSITION OF SEBACEOUS MATTER. 

 Animal substances . . . 

 Fatty matters ....... 



Phosphate of lime 



Carbonate of lime ...... 



Carbonate of magnesia 



Chloride of sodium \ 

 Acetate of soda, &c. 



358 



368 



200 



21 



16 



37 



1000 



Owing to the large proportion of stearine in the fatty ingredients 

 of the sebaceous matters, they have a considerable degree of con- 

 sistency. Their office is to lubricate the integument and the hairs, 

 to keep them soft and pliable, and to prevent their drying up by 



Simon's Chemistry of Man, p. 379. 



