VERNIX CASEOSA 287 



found in great number. 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 cutaneous surface and give to the hairs the 

 softness characteristic of them in a healthy condition. 



The chemical constituents of the sebaceous matter are largely fatty. 

 The solid matters consisted of olein, 270 parts, palmitin, 135 parts, 

 caseous matter, 129 parts, gelatin, 87 parts, a little albumin, butyric 

 acid and sodium butyrate, with sodium phosphate, sodium chloride, 

 sodium sulphate and traces of calcium phosphate. Cholesterin, which 

 is present so frequently in the contents of sebaceous cysts, does not 

 exist in the normal secretion. 



During the later months of pregnancy and during lactation, the 

 sebaceous glands of the areola of the nipple become distended with a 

 grayish white opaque secretion containing oily globules and granules. 

 Frequently the secretion also contains a large number of epithelial cells. 

 During the periods above indicated, the secretion here is always much 

 more abundant than in the ordinary sebaceous glands. 



Smegma of the Prepuce and of the Labia Minora. In the folds of 

 the prepuce of the male and on the inner surface and folds of the labia 

 minora in the female, a small quantity of a whitish grumous matter, of 

 a cheesy consistence, is sometimes found, particularly when proper at- 

 tention is not paid to cleanliness. The matter which thus collects in 

 the folds of the prepuce has really little analogy with the ordinary 

 sebaceous secretion. Examination with the miscroscope shows that it 

 is composed almost entirely of irregular scales of epithelium, which do 

 not present the fatty granules and globules usually observed in the cells 

 derived from the sebaceous glands. The production of this substance 

 probably is independent of the secretion of sebaceous matter, as it is 

 formed chiefly in parts of the prepuce in which the sebaceous glands are 

 wanting. 



The smegma of the labia minora is of the same character as the 

 smegma preputiale ; but it contains drops of oil and the other products 

 of sebaceous glands found in these parts. 



Vernix Caseosa. The surface of the foetus at birth and near the end 

 of utero-gestation usually is covered with a whitish coating, or smegma, 

 called the vernix caseosa. This is most abundant in the folds of the skin; 

 but it nearly always covers the entire surface with a coating of greater 

 or less thickness and of about the consistence of lard. There are great 

 differences in foetuses at term as regards the quantity of vernix caseosa. 

 In some the coating is so slight that it is observed only on close inspec- 

 tion. There are few analyses that give accurately the chemical com- 

 position of this substance ; and the best idea of its constitution and 



