OF THE SKIN. 1 15 



resemble one another, is as little obvious as the cause of the 

 somewhat defined line of demarcation between the two layers, a 

 condition which appears still more strikingly in the nails, and 

 would lead one to suppose that, at the first formation and in 

 the course of the development of the epidermis and nails, a very 

 considerable alteration suddenly takes place at one point in 

 their cells, thus determining their separation into two layers. 



[In the deep fold of the skin which surrounds the glans 

 penis and clitoridis, a continual desquamation and reproduction 

 of the epidermic scales, which are here soft and nucleated, 

 takes place, in consequence of which a peculiar secretion, the 

 smegma preputii, is produced. Hitherto this secretion has been 

 erroneously, but almost universally, supposed to be a sebaceous 

 matter secreted by the preputial glands. The microscope 

 shows: 1, that in the female, where the presence of smegma 

 preputii is constant, neither sebaceous nor any other glands 

 exist upon the prepuce or glans clitoridis ; 2, that in the male, 

 in whom such glands are indeed found, they are commonly 

 but insignificant in relation to the quantity of smegma, and 

 are often very few and scattered ; 3, finally, that the smegma, 

 in both sexes, consists principally of cells of the same form as 

 those of the prepuce and glans penis and clitoridis ; whence, 

 taking also into account the fact, that in the male it is 

 generally distinctly composed of superimposed layers covering 

 the whole prepuce continuously, whilst the sebaceous glands 

 occur only isolated, it naturally follows that the smegma is 

 principally constituted of desquamated epidermis. However, 

 this does not exclude the preputial sebaceous matter in the male 

 from also taking a share in proportion to the number and size of 

 Tyson's glands, in the formation of what goes under the common 

 name of smegma. There would in this locality then, really be a 

 constant desquamation of the external, and a new development 

 of the internal layers of the epidermis, but here there are special 

 purposes in view which elsewhere do not enter into consideration. 

 The preputial fold, in fact, is to be compared to a gland; and as 

 the secretions of these are very often formed onlv bv the continual 

 casting off of the cells which line them (e. g. sebaceous glands), 

 so is that of the prepuce. We must recollect that in many animals 

 e.g., the Weasel, the Beaver (E. H. Weber), without essentially 



i. 10 



