OK THE SKIN. 125 



a decisive voice in the matter. How the nerves in the papillae 

 of the lips, tongue, and elsewhere, are disposed, I have not yet 

 ascertained with certainty; but with regard to the first of 

 these, I believe I can also affirm, that they do not terminate in 

 the axile corpuscles, but either merely pass by them or wind 

 round them. In the lips, in a single instance, I found well- 

 marked nerve-coils in small papillae,, or at the base of the 

 large ones. 1 ] 



§ 38. 



Development of the Cutis. — The following may be taken as a 

 general sketch of the development in the foetus, of the cutis, 

 in the broadest sense of the term. It consists at first of cells, 

 which though not in man, yet in animals (the Frog, for in- 

 stance) may be easily traced back to the earliest formative cells 

 of the embryo. A considerable proportion of these cells are 

 changed into connective tissue, becoming fusiform, coalescing, 

 and eventually being converted into bundles of fibrils ; a 

 process which appears to occur first in the fascia superficialis, 

 the subcutaneous connective tissue, then in the pars reticularis 

 of the corium, and finally in the papillary layer. Another 

 portion of the cells are converted into vessels and nerves, as 

 can be seen even in man, and very beautifully in the Batrachia 

 (see my Memoir in the 'Annales des Sciences Naturelles, 5 

 1846) ; while a third, growing and developing fat in its interior, 

 becomes elastic fibres and fat-cells (vide supra, § 23). The 

 first foundations of all these parts having been laid, they con- 

 tinue to increase in a manner which is not yet exactly made 

 out. The cutis obviously grows from within outwards (so that 

 the papillae arise and are developed last of all), partly by the 

 growth of its primitive elements, partly at the expense of cells, 

 which are perhaps mostly of new formation, and do not pro- 

 ceed from the original formative cells. The panniculus adiposus 

 also increases, partly by the increase of the cells, of which it 

 at first consists, partly by the subsequent development of 

 others, as well as of connective tissue and vessels. In this 

 manner the skin grows for a long time after birth. In children 



1 [Mr. Dalzell, in a communication read before the Edinburgh Physiological 

 Society, January, 1853 ('Monthly Journal of Medical Science,' March, 1853), con- 

 firms Kblliker's account of the corpuscula (actus in all essential points. — Eds.] 



