CHAP, vi.] SOME OTHER SENSATIONS. 273 



distinct plexus analogous to the subepithelial plexus of the cornea, 

 give off numerous delicate fibrillae which, forming a network among 

 the cells of the malpighian layer, end in a manner similar to that 

 obtaining in the cornea, namely, in free ends, between the cells of 

 the upper region of the malpighian layer beneath the stratum 

 granulosum ; this latter layer apparently they never penetrate. - 



The penetrating fibres giving rise to these intraepithelial 

 fibrillae, pass into the epidermis at the tops and at the sides of the 

 papillae, as well as in the valleys between the papillae. As far as 

 can be ascertained, they are present in all regions of the skin, 

 being probably more abundant in some regions than in others. 

 Their relative abundance cannot be quantitatively determined 

 with exactness owing to the inconstancy of the gold chloride 

 method ; in the same region the method will disclose at one time 

 a very large number of tibrillas, at another time very few. We are 

 probably justified in asserting that this method of ending, by 

 means of intraepithelial fibrill*, is the general mode of ending of 

 the afferent nerve fibres distributed to the skin itself. 



875. In the epidermis of the pig's snout there are found in 

 the deeper regions of the malpighian layer between the papillae 

 and elsewhere, oval nucleated cells which differ from the ordinary 

 cells of the layer, both in their form, being oval not polygonal, in 

 the absence of prickles, and in their behaviour towards reagents, 

 especially gold chloride, with which they stain somewhat deeply. 

 Non-medullated nerve fibres penetrating the epidermis from the 

 dermis, and dividing into branches, pass to these cells, which 

 frequently occur in clusters, and each branch terminates in a sort 

 of plate or disc, which is applied closely to the under surface of 

 one of the cells, but apparently is not continuous with the sub- 

 stance of the cell. The cells are not so well developed as are the 

 cells of a corpuscle of Grandry, and the terminal plate has not such 

 a definite form as in that body ; but the resemblance between the 

 two is very striking. Moreover cells of this kind with the be- 

 longing nerve filaments have been observed lying partly within 

 the epidermis and partly in the dermis beneath. It would seem 

 as if these cells with their nerve filaments formed within the 

 epidermis an organ of the same nature as and probably playing 

 the same part as the corpuscle of Grandry in the dermis. 



Similar cells, which have been called " touch-cells," have been 

 observed in other regions of the skin of various animals, and are 

 well developed in the outer root sheath or malpighian layer of the 

 tactile hairs, such as those in the " whisker " of the cat. They 

 have been found in man in regions where the touch corpuscles are 

 sparse or absent, in the skin of the back, belly, arms, legs and 

 neck. It seems probable that further investigation will disclose 

 that they have a very wide distribution ; if so they will have to 

 be regarded as a significant mode of ending of the cutaneous 

 nerves. 



18 



