64 SECRETION. 



upon the cutaneous surface, that the amount of sebaceous 

 matter must be considerable, it has been impossible to collect 

 the normal fluid in quantity sufficient for ultimate analysis. 

 In certain parts, as the skin of the nose, where the glands 

 are particularly abundant, a certain amount of oily secre- 

 tion is sometimes observed, giving to the surface a greasy, 

 glistening aspect. This may be absorbed by paper, giving 

 it the well-known appearance produced by oily matters, 

 and may be collected in small quantity upon a glass slide 

 and examined microscopically. It then presents a number 

 of strongly refracting fatty globules, with a few epithelial 

 cells. The cells, however, are not numerous in the fluid as 

 it is discharged upon the general surface ; but if the con- 

 tents of the ducts and follicles be examined, cells will here 

 be found in great abundance. Most of the cells, indeed, 

 remain in the glands, and the oily matter only is discharged. 

 The object of this secretion is to lubricate the general cuta- 

 neous surface, and to give to the hairs that softness which 

 is characteristic of them when in a perfectly healthy con- 

 dition. 



It is only when the action of the sebaceous glands has 

 become more or less modified, that the secretion can be 

 obtained in sufficient quantity for chemical analysis ; but we 

 cannot be certain that the fluid taken under these conditions 

 is perfectly normal. The analysis by Esenbeck, 1 which is 

 often quoted in works on physiology, was the result of an 

 examination of the contents of a largely distended hair- 

 follicle ; and as the secretion was confined for a long time, it 

 is evident that it must have undergone material alteration. 

 We cannot, indeed, refer to any ultimate analysis of the 

 normal sebaceous secretion ; but of all the examinations 

 that fyave been made of the secretion when it has been 



1 ESENBECK, Chemische Untersuchung des Inhalls einer vergrosserten Talgdrusse 

 der Haul (glandula sebacea) oder einer sagennanten Fettbalg-Gcschwulst (Athe- 

 roma). KASTNER'S Archiv far die gesammete Naturlehre, Niirnberg, 1827, B. xii., 

 S. 460, et seg.) 



