294 PROFESSOR MATTEUCCI’S ELECTRO-PHYSIOLOGICAL RESEARCHES. 
divided ; the contractions are very strong at first, but they soon diminish in strength, 
and that rapidly. 
It would therefore be a mistake to conclude that muscular contraction increases 
because the nerve traversed by the eleetric current has been separated from the ner- 
vous centre : we have seen what is the true explanation of the phenomenon, and that 
this conclusion is only apparent. 
On the other hand, these experiments prove, as did also those of the preceding 
section, that the excitability of a nerve is not altered by its separation from the ner- 
vous centres, or, rather, that the only alteration which it undergoes consists in the 
increased rapidity with which the excitability diminishes under the action of stimu- 
lants. Thus, the contraction produced by the passage of an electric current through 
a nerve is sensibly the same, whether this nerve be in communication with the nervous 
centres, or separated from them for several hours, or an instant after the separation 
has been effected : when the action of the current is repeated, its effects diminish 
the more rapidly exactly in proportion to the length of time which has elapsed since 
the separation of the nerve from the nervous centre. 
I think it is scarcely necessary for me to remark, that these conclusions are not 
contrary to those of Muller and Longet ; according to which it was shown that 
when the nerves had been separated from the central mass, for weeks and months, 
the sensibility of these nerves and the irritability of the muscular fibre were diminished. 
M. Longet has given the interpretation of this phenomenon, grounded on experiment. 
In order to complete the first part of this memoir, I now proceed to relate the 
experiments and considerations by which the strict analogy existing between elec- 
tricity and nervous force, together with the nature of that analogy, are demonstrated 
in a most satisfactory manner. 
At the beginning of this memoir, referring to my preceding researches in electro- 
physiology, I mentioned the law according to which, by the influence of the nervous 
current, a development of electricity takes place in the organ of electrical fishes. 
We shall now consider what may be called the converse of this phenomenon, that is 
to say, the development of nervous force under the influence of the electric current, 
which development is produced exactly according to the same law as that of elec- 
tricity by nervous force. This influence of electricity on nervous force is manifested 
in the muscular fibre : we have already observed at the beginning of this memoir 
that the phenomena presented by the organ of electrical fishes, as well as those of the 
muscular fibre, together with the modifications of these phenomena under various 
circumstances, invariably followed the same course, and preserved the strictest ana- 
logy with each other, so that what was true with regard to the electrical discharge of 
the torpedo, was equally so with regard to muscular contraction. 
This fact admitted, we proceed to the experiments. 
Expose in a living dog, rabbit or frog, the muscles of the thighs, removing entirely 
the skin and membranes, then transmit through the muscles the electric current 
