124 OF MIND. 



under most favourable circumstances, has forced me to dis- 

 sent entirely from both views. In every case in which I 

 have been able to demonstrate the finest nerve fibres I have 

 succeeded in proving the existence of germinal matter in 

 connection with them. 



There is, however, no doubt that nerve action is influ- 

 enced by pressure upon the fibre of a nerve without any 

 change in germinal matter. In many nerves of the higher 

 animals a considerable length of axis cylinder intervenes 

 between the nerve centre and the peripheral distribution of 

 the nerve fibres, which is destitute of germinal matter, but 

 which, nevertheless, receives and transmits nervous impres- 

 sions made upon it in this part of its course. So that, although 

 absence of germinal matter from a considerable extent of 

 peripheral nerve fibre does not justify the conclusion that 

 the nerve fibre in question is not an active fibre, the mere 

 statement that very fine fibres have been seen amongst 

 epithelial or other cells, and constitute the essential part of 

 the peripheral nerve apparatus, must be received with the 

 greatest caution. Until these supposed nerve fibres have 

 been actually followed into undoubted nerve trunks, and 

 the manner in which they were formed has been clearly 

 pointed out, we cannot be expected to assent to the conclu- 

 sion that the appearances described are really due to nerves 

 at all. In all tissues of vertebrata in which I have studied 

 the very fine peripheral nerve fibres, I have succeeded in 

 tracing them into undoubted nerve trunks, and I have 

 always detected numerous masses of germinal matter in 

 connection with these fibres, as will be found figured in my 

 drawings. Moreover, the germinal matter is more abun- 



