CHAP. XI. NOT CDBRBNT FORCE. 145 



the needles having become magnetised. Upon 

 testing the needles after the experiment with steel 

 filings, it was frequently observed that the filings 

 adhered to the needles throughout its whole extent, 

 although they had been previously wiped with a dry 

 clean cloth. These effects were evidently due to the 

 needle being damp ; the moisture from the fingers 

 was sufficient to produce this damp state, and the 

 only mode of preventing it was by heating the 

 needle, but by so doing, any magnetic state it might 

 possess would be destroyed. The difference ob- 

 served in the needles in which the filings adhered 

 when magnetised or when damp is very great; in the 

 latter the whole surface is slightly covered with 

 them, but in the former the filings are confined to 

 one or two spots. 



The results of the present investigation only tend 

 to confirm the opinion already expressed by Mullek, 

 Matteucci, and others, that rierve force is not iden- 

 tical with current force. Or the conclusion may 

 perhaps be more correctly expressed by saying, that 

 we have not been enabled to obtain any evidence of the 

 manifestation of current force in a nerve dwring nerve 

 action. It must be borne in mind, however, that 

 I am now speaking of nerve action, and not dis- 

 proving the existence of the so-called nerve current 

 which is manifested in a nerve during its quiescent 

 state : and this brings before us another most 

 important question for consideration, viz. 7s this 

 nerve current affected during nerve action ? 



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