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PROFESSOR MATTE UCCl’S ELECTRO-PHYSIOLOGICAL RESEARCHES. 
served that I have not taken any account in this memoir of the sensations awakened 
by the passage of electricity in the nerve. 
To complete this memoir, it only remains for me to show how the different pheno- 
mena, produced by the passage of the electric current through the nerve, may be 
arranged in groups founded upon the two principles quoted and deduced immediately 
from experiment. In this manner I hope to redeem my pledge of giving a theory of 
the physiological action of the electric current. It is only in this manner that the 
advance of the physical sciences can be promoted, by deducing, that is to say, the 
greatest number of facts possible from the smallest number of elementary facts. I 
do not indeed pretend to affirm that the two principles upon which I take my stand, 
and which are immediately deduced from experiment, are the simplest and most 
elementary facts in so vast a field as that of the connection between the electric and 
nervous phenomena ; but it is certain that a great number of electro-physiological 
facts, which existed without any mutual relation, are now brought under the de- 
pendence of two fundamental facts. The manner in which a mixed nerve, subjected 
to the passage of the electric current, presents different phenomena according to the 
degree of its excitability, is this. In the first period of its excitability it is natural 
that the contraction should take place, whatever be the direction of the current in 
the nerve. On breaking and on closing the circuit, the electric discharge, which 
if the pile were strong enough would be accompanied by a spark, always takes place 
whatever be the direction of the current; consequently there ought to be contrac- 
tion in every case. When the excitability of the nerve comes to be diminished, 
either by the passage of the current, according to the law which has been established, 
or naturally, the effects of the electric discharge can no longer be the same ; when 
the direct current has been passed for some time there will be no contraction pro- 
duced by the discharge which accompanies the breaking the circuit. By degrees, 
as the excitability becomes naturally enfeebled in the nerve, the contraction pro- 
ceeding from the discharge, which takes place on closing the inverse circuit, will 
be found to disappear. From the excitability produced in the nerve by the passage 
of the inverse current, contraction will be produced by the discharge which accom- 
panies the breaking of the inverse circuit. The alternatives of Volta may be ex- 
plained in a like simple manner. A nerve, of which the excitability has been de- 
stroyed by the passage of the direct current, reacquires its lost excitability under the 
action of the inverse current ; and it is thus that contraction should occur on break- 
ing the inverse circuit, when there was no contraction on closing the direct circuit. 
According to the state of the nerve, the increase of excitability persists or subsides 
immediately after the passage of the inverse current. If the latter case occurs, there 
is never any contraction except on breaking the inverse circuit, while in the former 
case the contraction may likewise occur on closing the inverse circuit. It is inva- 
riably the case that the strongest of these two contractions is that which accompa- 
