272 NERVOUS SYSTEM. L.ECT. XIV. XV. 



and are almost always due to some too brusque movements 

 in the elements, in consequence of which the contacts are 

 deranged. 



We therefore conclude, that direct experiment replies 

 negatively to the question which we put whether there was 

 a development of electricity during muscular contraction. 



There now remains to be explained the phenomena pre- 

 sented by the proper current, when we employ entire frogs, 

 and which consist of the almost constant occurrence of signs 

 of augmentation, when we, for the first time, touch the 

 lumbar plexuses of the frogs with potash ; whereas, on the 

 contrary, when we apply an acid solution to them, the needle 

 immediately descends. I have repeated and varied for this 

 purpose my first experiments, and the following is the way 

 in which these differences may be explained. 



Whatever be the form of the muscular elements which 

 we use to make the pile, that is, whether they be made 

 with entire frogs, with half- thighs, or such as we have de- 

 scribed, when we moisten the surface of the muscular ele- 

 ments with an acid, or alkaline solution, it invariably 

 happens, whether there be or be not contractions, that the 

 deviation diminishes, and that the needle returns to 0, 

 where it stops, if either the application of the alkali be re- 

 peated, or the solution employed be too concentrated. 



This effect is analogous to that already described, and 

 which the muscular elements present when they have been 

 plunged for a few seconds into acid, or alkaline solutions. 



In our mode of experimenting, we excite the contractions 

 in the muscles by touching with alkali those points which 

 are out of the circuit, and which do not constitute parts of 

 the electromotive element. 



In piles formed of entire frogs, with which we most fre- 

 quently succeed in obtaining, in a transient manner, signs 

 of augmentation in the current, by touching the lumbar 



