270 NERVOUS FORCE. L.ECT. XIV. XV. 



have been plunged into a solution of common salt, and 

 afterwards washed, a deviation of about 60 only at first, 

 and afterwards the needle stops at 8 or 10. We shall 

 remark the agreement between this result and that to which 

 Dumas has recently arrived, when investigating the in- 

 fluence of certain salts on the arterialization of the blood. 



We are, then, led to conclude, that the effect of these 

 alkaline, acid, or very concentrated saline solutions, is to 

 destroy in the muscular elements those conditions necessary 

 to the development of electricity. This conclusion is in 

 no way opposed to the origin we have assigned to this 

 current. But since, by the action of acid or alkaline solu- 

 tions, the signs of the muscular current either cease, or are- 

 very much weakened, it remains for us to explain how, in 

 the preceding experiments, there has been no diminution of 

 the current in a pile of entire frogs, when these have been 

 touched at certain points with alkaline solutions, while it is 

 immediately manifested when they are washed in an acid 

 solution. In fact, you have remarked that, when we em- 

 ploy alkali, there is, in many instances, a remarkable aug- 

 mentation of deviation, although of short duration, in the 

 first contractions excited. With acids, on the contrary, the 

 deviation immediately diminishes, but appears again some 

 instants after. 



Let us endeavour to give an account of these phenomena- 

 But first, I should describe the experiments which I have 

 made in a most careful manner, with the view of discovering 

 if there be a development of electricity during muscular 

 contraction. 



I prepare several frogs according to the usual manner of 

 Galvani. I then remove their legs, disjointing them with 

 the greatest care. I have, thus, two thighs of a frog, united 

 to a portion of the spinal marrow,; I cut one of the thighs 

 in half, and prepare, in the same manner, a certain number 



