1 36 NEBVE FORCE. CHAP. XI. 



into the brain, and the other into the muscles, when 

 a deviation of the needle to a large amount occurred, 

 the electrode in contact with the muscle being 

 positive to the other. In this instance, it might be 

 supposed that the current travelled from the brain 

 along the nerve to the muscle. I have alluded to 

 these experiments in chap. vi. ; and as similar effects 

 upon the needle were obtained when the electrode 

 was inserted into the internal jugular vein instead 

 of the muscle, I have been led to suppo'se that the 

 effects are due to the electric condition of the 

 nervous tissue, the result of nutrition, and not as 

 indicating the passage of an electric current along 

 the nerve. 



Pbevost* and Dumas'", Peeson*, Muller*, and 

 Matteccci", have failed to obtain any evidence of 

 current force being manifested when the electrodes 

 of the galvanometer were inserted in the nerves of a 

 living animal. Some of my earliest experiments 

 were undertaken for the purpose of ascertaining this 

 point; and although results were occasionally ob- 

 tained, nevertheless, as the experiments were per- 

 formed prior to the knowledge of the existence of 

 the electric condition of the nervous tissue, I have 

 no doubt that the effects then observed were due to 

 the circumstance that the electrodes were placed on 

 heterogeneous parts of the nerve, as I shall be able 

 to shew presently. 



ii MuiiEB's Elements, pp. 686 — 689. 



' Traitfe des Fh^nom^nes Electro Physiologiques, p. 253. 



