LECT. XIV. XV. MUSCULAR MORE ENERGETIC. 267 



tion is greater for the second than for the first; indeed, when 

 forming a pile with half-frogs, prepared by cutting the thighs 

 in halves, I found a differential current more or less con- 

 siderable, but always in the direction of the muscular 

 current. It is only with very lively frogs, by dividing the 

 thigh very high up, and by leaving only a small part of the 

 surface of the interior of the muscle exposed, that we find 

 no sign of the differential current, or, that it exists, in the 

 direction of the proper current. Such was the fact which 

 I discovered in my first experiments, and which, since my 

 more recent ones, I can explain in a more satisfactory 

 manner, by considering that in leaving the thigh nearly 

 entire, we have two elements, namely, the muscles of the 

 leg and those of the thigh, which give a current in the same 

 direction ; whilst the muscular element which furnished the 

 current in the contrary direction is a single one. 



Is Electricity evolved during Contraction ? To return to 

 our principal subject, I may observe, that I have employed 

 a muscular pile in order to ascertain whether there was a 

 development of electricity during the contraction of a mus- 

 cle. But seeing that in order to excite the latter I was 

 compelled to moisten the muscles with acid, saline, or, 

 better still, alkaline solutions, I thought it right first to 

 direct nay attention to the action of these liquids on the 

 muscular current. 



With this object I took eight frogs from among a very 

 great number, and prepared them in the usual manner, by 

 making with them sixteen elements, or half-thighs. I 

 closed the circuit; the needle oscillated to 90, and stopped 

 at 22. I formed another similar pile, but with this differ- 

 ence, that I washed the half-thighs several times in pure 

 water, and afterwards dried them: I obtained the same 

 result. Sixteen other elements like the latter were put, for 

 some seconds, in a weak solution of sulphuric acid, then 



