68 BEING AND FACULTIES OF MAN. 



cular motion ; and having satisfied ourselves of this much 

 it is now our duty to investigate what known law of 

 electricity such a motion coincides with. This, in the 

 advanced state of electric science, is fortunately not diffi- 

 cult to find. M. Ampere's theory of electric currents 

 supplies us with the fact that two parallel, or nearly 

 parallel, currents of electricity, when proceeding in the 

 same direction, attract each other, and when proceeding 

 in opposite directions, or counter to each other, they repel 

 each other. We have only therefore to suppose that when 

 the electricity passes along the fibres of the muscle in the 

 same direction they attract each other, and the belly of 

 the muscle collapses, the muscle being extended; and 

 that when the currents of electricity proceed in opposite 

 directions, that is, so many of them along one set of the 

 muscular fibres from one end of the muscle the tendinous 

 origin, for example and so many more of them proceed 

 from the opposite end of the muscle, or the tendinous 

 insertion, these currents passing each other through the 

 belly of the muscle repel each other and swell the belly, 

 thereby causing the muscle to contract. The immense 

 number of fibres in a powerful muscle, and the number of 

 electric currents thus passing along them, will readily 

 account for the great strength and literally electric 

 rapidity of muscular action ; and we know of no other 

 explanation which furnishes the faintest indication of an 

 adequate cause for this familiar, but not the less remark- 

 able phenomenon. If there be any other force which can 

 produce this action, mankind, as yet, know nothing of it. 

 We do know that electricity can, and does cause it, and we 

 also know that the above is the only law of electricity 

 man has been able to discover by which it can be done in 

 harmony with muscular organization, and that it is a law 

 adequate to the result. We also know that it is by pass- 

 ing through the muscle that electricity causes muscular 



