60 ELEMENTS OF NERVOUS TISSUE. 



This, however, is not, as yet, susceptible of demon- 

 stration. Nerve fibres remain" entire whilst in the 

 nervous centres, and throughout their whole course ; 

 but, at their peripheral extremities, most of them 

 divide into branches. This fact is perfectly made out 

 as far as the nerves of motion are concerned, as we 

 have already seen whilst studying the structure of 

 striped muscle. It is probably true also of the nerves 

 of mucous membranes, and of the external integu- 

 ment. 



Their mode of termination, which has been a sub- 

 ject of research for so many minute anatomists, is not 

 yet definitely established for all the tissues. It ap- 

 pears to be susceptible of demonstration that in the 

 ganglia, and other nervous centres, nerve fibres are in 

 contact with nerve cells. It is equally beyond doubt 

 that in the muscles, and in certain regions of the skin 

 and mucous membranes, nerve fibres, after undergoing 

 division, terminate by free extremities (as in muscle), 

 and sometimes by again anastomosing with each other 

 (as in the skin and mucous membrane of the tongue). 

 The experiments of Prof. Cl. Bernard, on the phe- 

 nomena of recurrent sensibility, tend to prove that a 

 large proportion of sensitive fibres end by forming 

 loops. We shall see hereafter that in the eye, the 

 ear, and the olfactory mucous membrane, they termi- 

 nate by contact with nerve cells, as in the nervous 

 centres. Finally, in the integument of the palm of 

 the hand and sole of the foot, we find, in fibres of 

 sensation, two peculiar modes of termination, viz. the 

 corpuscles of Pacini and corpuscles of Meissner, which 

 we are about to describe. 



