152 SPECIAL HISTOLOGY. 



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 altera- 

 tion 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 clito- 

 ridis, 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 pre- 

 puce 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 dis- 

 tinctly composed of superimposed layers covering the whole prepuce con- 

 tinuously, whilst the sebaceous glands occur only isolated, it naturally 

 follows that the smegma is principally constituted of desquamated epi- 

 dermis. 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 con- 

 stant desquamation of the external, and a new development of the in- 

 ternal 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 only by 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 changing the character which it possesses 

 in man, the prepuce takes on a highly glandular nature, and that even 

 in man it yields a secretion which differs considerably from common epi- 

 dermis. According to Lehtnann, the yellow, fatty, strongly-odorous 

 preputial smegma of man contains, when dried, in 100 parts : Ethereal 

 extract, 52*8 ; alcoholic extract, 7*4; aqueous extract, 6*1; earthy salts, 

 9'7 ; albuminous substances soluble in dilute acetic acid, 5-6; insoluble 

 residuum, 18'5. The ethereal extract contained saponifiable fat, choles- 



