CUTAT^fEOUS NERVE-TEKMTKATIO]S'S TlSr MAMMALS. 587 



itself. That figure was by no means an exceptional one ; indeed 

 every specimen we possessed, in above a hundred cases, showed 

 all the same condition ; and in some cases the two fibrils resulting 

 from the breakage of the loop or arch lay side by side, each push- 

 ing out lateral branches after the manner shown in fig. 24. The 

 same tendency is shown in the fact referred to in tlie previous 

 chapter, that, even while the termination of the nerve-fibril is 

 undergoing degeneration in the inert layers of the epidermis, it 

 may be pushing out branches from its living portion, which are 

 carried out with it nearly at right angles to the epidermis to perish 

 in the inert layers. That those fibrils appear generally to lie at 

 right angles to the surface is due, we think, solely to the rapidity 

 of the growth of the epidermis ; and they will also be found most 

 numerous where, amongst other tilings, growth of epidermic cells 

 is going on fastest. At the surface or summit of the vascular 

 papilla, the growth of epidermic cells seems to go on more rapidly 

 than elsewhere ; and thus it is that the entanglement of nerve- 

 fibres, as shown by their greater number, seems to go on much 

 faster there than on the interpapillary portions of the surface of 

 the epidermis, where the fibrils are much fewer. If this be true, 

 we should naturally expect that, on portions of the epidermic sur- 

 face which were unexposed to rubbing or wearing, the growth of 

 the cells would be slow, and any intraepidermic nerves which 

 were found there, instead of being carried rapidly at right angles 

 to the surface, would find time to ramify laterally. This is exactly 

 what happens in the protected epidermic lining of the hair-follicle, 

 as shown in fig. 17, Plate XIV., where the fibrils find time to 

 exercise their natural tendency to lateral development, instead 

 of being hurried through at right angles to the surface. "We 

 submit, therefore, that we have showu Ranvier's hypothesis to 

 be untenable. 



Subepidermic Plexus of Nerve-cells and Fibres. 

 "We have often referred, in the course of this paper, to this 

 plexus as an important element in the cutaneous nerve-supply, 

 and described it (p. 576) as being almost an independent system, 

 although no investigator, to our knowledge, calls attention to it. 

 This we believe to be due to the difficulty of showing it, as a 

 plexus of non-meduUated fibres, from the plane of the surface of 

 the skin ; and we were only enabled to do so by certain tech- 

 nical modifications devised by ourselves. It cannot be shown 



