182 MUSCULAR CURRENT. LiECT. IX. 



I first place one of these demi-thighs in such a manner 

 that its external surface is contained in one of these cups. 

 Next to this I place another, in such a position that its ex- 

 ternal surface is in contact with the internal surface of the 

 first ; and in this way, one after the other, all the demi- 

 thighs are arranged in a row, touching one another, and 

 with the same surface always turned in the same direction. 

 The last demi-thigh, like the first of the series, should be 

 placed in one of the cups of the tray, but by its internal 

 surface. 



Here, then, we have a pile of demi-thighs of frogs, of 

 which one extremity is formed by the external surface of 

 the muscle, the other by the internal surface. I fill the two 

 cups with a weak saline solution, or even with distilled wa- 

 ter; plunge into them the two extremities of the galvanome- 

 ter, and immediately I observe a deviation of the needle, 

 which before the immersion of these conductors was at 0. 



Thus, then, the presence of an electric current produced 

 by a pile formed of the muscles of the frog is demonstrated 

 by the galvanometer. Vary the experiments as much as 

 you like ; in lieu of the muscles of frogs, use the muscles 

 of other animals, of fishes, birds, or mammals, and, pro- 

 vided that you keep the relative position of the muscular 

 elements, before pointed out, namely, the internal surface 

 next to the external of the muscle, you will always obtain a 

 deviation more or less great of the galvanometer needle : 

 this deviation will indicate constantly, by its direction, the 

 presence of a current proceeding in the pile from the inter- 

 nal to the external surface of the muscle. 



I must observe that the intensity of the current is in pro- 

 portion to the number of demi-thighs employed to form the 

 pile. Here is a pile formed of ten demi-thighs ; the varia- 

 tion of the needle is from 30 to 40 ; here is another with six 

 elements, and the needle marks from 10 to 20 ; in a 



