CHAP. Vnr. MUSOULAR AND NEBVOUS TISSUES. 77 



eluding that the electro-motive force of muscles 

 increases both with their length and thickness. 



5. If the two ends — the divided or artificial trans- 

 verse sections — of a muscle or of a nerve be placed 

 between the electrodes of a galvanometer, no effect 

 occurs upon the needle ; but if one of the electrodes 

 be placed upon the surface or longitudinal section, 

 the other remaiaing in contact -with the transverse 

 section, the current is produced according to the 

 law expressed in Proposition I. 



6. If the electrodes be placed upon two symme- 

 trical portions of the surface of the muscle or of the 

 nerve, no effect is produced upon the needle. 



The following experiments were now performed : 

 A muscle or nerve was divided into three or more 

 portions, and then so arranged that the internal 

 should form the outer portions, the continuity of the 

 nerve being maintained. When the electrodes were 

 placed at the two extremities, or upon symmetrical 

 portions of the nerve or muscle, no effect, or, if any, 

 but very slight indications were occasionally pro- 

 duced upon the needle ; if the external surface and 

 the divided surface were formed into a circuit, the 

 current was obtained ; and also when the portions 

 were so arranged, that the external surface of one 

 portion was placed in contact with the transverse 

 section of another, then the current was obtained, as 

 in Matteucci's experiment, when forming a pile of 

 muscular elements. These experiments, which I 



