THE PHYSIOLOGICAL ACTION OF THE ELECTRIC CURRENT. 
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nies the breaking' of the inverse circuit. It is scarcely necessary to say, that if the 
nerve has been previously traversed by the inverse current, before subjecting it 
to the passage of the direct current, the contraction in this case ought to be much 
stronger than that which took place before on opening the circuit. The unequal 
effect, according to the direction of the same discharge through a nerve, has been 
clearly demonstrated by experiment. Volta and Marianini have studied the vol- 
taic alternatives by passing the current through muscular masses and along nerves, 
but without acting separately upon one nerve with the direct and another with the 
inverse current. Thus it happens, that in this way of operating, in the same mus- 
cular mass there are some nervous filaments traversed by the direct current, and 
others traversed by the inverse current. Starting from this principle, it is easy to 
refer the fine experiments of Volta and Marianini to the explanation which we have 
already given of the voltaic alternatives. 
Pisa, March 22, 1846. 
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