CHAP. XI. CONCLUDING BEMARKS. 157 



It must be remembered, that we have hitherto 

 limited our views, and have been comparing nerve 

 force with only one of the ordinary polar forces with 

 current force. Let us now compare it in regard to 

 magnetic action. In a magnet we can get no evi- 

 dence of cun-ent force travelling />-oot one pole to the 

 other; the force exists in a state of tension, which 

 may be raised or lowered without affecting the 

 galvanometer when arranged with the electrodes at 

 the two ends. May not nerve force exist in a state 

 of tension, and nerve action correspond with a rising 

 or lowering of this state, just as the muscular fibre 

 may be regarded as existing in a state of electric 

 tension and muscular contraction, the result of a 

 lowering of its tension ? The developement of the 

 force in the fish, and other facts, may perhaps be 

 adduced as an argument against this supposition, 

 and in favour of transmission of force from one 

 point to another along the nerve. But even here an 

 increase or a lowering in the tension of one part 

 may be accompanied with a lowering or an increase 

 in the tension of another part ; the final result being 

 tantamount to the transmission of force from one 

 part to another. Still it behoves us not to keep 

 limiting our views to one class of actions only, but 

 to be bold and suggestive, and seize upon any 

 resemblances, however slight; and provided we do 



force and of current force. The ligature of a nerve preventing 

 the transmission of nerve force, is a strong argument against 

 the identity of these two forces. 



