OF yiTAL MOTION. 87 



tions disappear, there being only contraction on 

 closure of the circuit when the current passes towards 

 the foot, and on disruption when it passes towards the 

 thigh. 



Now these results are not altogether unintelligible, 

 if we attentively consider all the premises. It may 

 be granted, in the first place, that there is a current 

 of electricity in the limb which is used to test the 

 activity of the pile, in the same direction as in the 

 limbs which compose the pile, namely, from the foot 

 towards the thigh. It may be granted, also, that by 

 adding this limb to the pile in the proper manner, the 

 activity of the electric current would be intensified; 

 and if it were inverted so that the thigh were added 

 to the thigh instead of to the foot extremity of the 

 pile, it may be granted also that this mal-arrangement 

 will neutralize to a certain extent the energy of the 

 current, just as would be the case if we were to add a 

 pair of plates to a galvanic battery, in such a manner 

 that platinum faced platinum, or zinc zinc, instead of 

 observing the natural order and causing the zinc and 

 platinum to oppose each other. And further, it may 

 be granted that the limb which is made the subject of 

 the experiment is virtually a part of the pile, though 

 it be only connected by conductors, and that it must 

 neutralize or intensify the energy of the electric cur- 

 rent, just as much as if it were more obviously a part 

 of the pile. 



