SKIN AND ITS APPENDAGES. 



gers and toes, and upon the palms of the hands and 

 soles of the feet ; some of them, in these localities, are 

 even surmounted by secondary papillae. 



The papillae, as well as the portion of the derma 

 from which they project, are composed of very deli- 

 cate fibrous tissue, containing a large number of plas- 

 matic cells (fig. II. 5), and tunnelled by the terminal 

 branches of the vascular and nervous systems. The 

 papillary surface of the true skin is limited by a very 

 delicate structureless membrane (reVoth of a line in 

 thickness), which separates it from the epidermis 

 (fig. II. 4). 



The blood-vessels of the skin form two sets : one vessels. 

 occupies the deep stratum, and supplies the glands, 

 hair follicles, and pellets of fat; the other, in the 

 shape of a close network, is found spread out in the 

 superficial layer, where it gives off the terminal 

 loops which penetrate the interior of most of the 

 papillae. 



The nervous filaments of the deep layer, few in -s ervef . 

 number, are destined for the supply of the organs 

 which it contains, whilst those of the papillary layer are 

 very numerous, forming a plexiform network which 

 seems to terminate, after previous sub-divisions, by 

 free extremities. A large number of these ultimate 

 nervous filaments enter the bases of a certain propor- 

 tion of the papillae (nervous papillae), and terminate 

 there either by free extremities, more rarely by form- 

 ing loops, or lastly by olive-shaped extremities, which 

 constitute the tactile corpuscles already described 

 (PL XXIII. fig. II. 6). It will be recollected, also, 

 that the Paccinian corpuscles constitute another mode 



