. IX. AGENCY OF THE NERVES. 183 



third, composed of four elements, it deviates only from 6 

 to 8 at the utmost. The increase of the intensity of the 

 muscular current, in proportion to the number of the mus- 

 cular elements employed to form the pile, is constant, 

 whatever may be the animal from which the muscles are 

 taken. 



If, in place of arranging the elements in a straight line 

 to form the pile, you dispose of them in such a way that 

 they form a semicircle, and thus shorten the distance be- 

 tween the poles, you may close the circuit with the single - 

 nerve of the galvanoscopic frog, and by its contractions in- 

 fer the existence of the electric current. 



Currents in other Tissues. I wished to ascertain whether 

 the other tissues and organs of animals, the membranes, 

 the nerves, the brain, the liver, and the lungs, denoted 

 the presence of an electric current. I have invariably ob- 

 tained very feeble signs of it. The heart alone gave indi- 

 cations of a very strong current ; but, as you know, the 

 heart is a muscle. 



It is unnecessary for me to tell you that I tried the 

 analogous experiments on the membranes, liver, &c., by 

 forming the pile with portions of these tissues or organs, 

 as in the case of the muscles, and that I took the same 

 precautions. 



Agency of the Nerves. Thus the current, of which we 

 have hitherto spoken, is principally demonstrated in the 

 muscles. This property does not depend on the nervous 

 system. Many of the experiments which I made, and 

 which are related in my work, already alluded to, con- 

 vinced me that if the nervous system which supplies the 

 muscles be destroyed, the latter do not lose the property 

 of manifesting the electrical current. I formed piles with 

 muscles deprived of their nerves with every possible care ; 

 with other muscles taken from frogs, a considerable part 



