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XIII. Electro-Physiological Researches. — Fifth Series. Part I. Upon Induced Con- 
tractions. By Signor Carlo Matteucci, Professor in the University of Pisa, 8$c. fyc. 
Communicated by Michael Faraday, Esq., 8$c. 8$c. 
Received May 20, — Read June 10, 1847. 
In my third memoir upon Induced Contractions, published in the Philosophical 
Transactions for 1845, at p. 303, after having discussed at length the various hypo- 
theses which appear to offer an explanation of this phenomenon, I was led to conclude 
that it was due to nervous influence acting through the muscle during contraction ; 
that, in a word, it was to be referred to a kind of nervous induction. In effect, I de- 
tailed a number of experiments in that memoir, which prove that there is never any 
manifestation of the signs of an electric current during the contraction of the muscles ; 
thus in exciting contractions in one of my piles composed of muscular elements, in 
which the circuit was completed by the galvanometer, the signs of the muscular cur- 
rent were never perceived to increase. Finally, I have shown that the induced con- 
traction is propagated through a coating of turpentine, which is of a nature suffi- 
ciently insulating to arrest the passage of any electric current. 
I was therefore warranted in deducing from these phenomena that in the muscles 
which contracted, and so produced the induced contractions, there was never any elec- 
tric current generated, and that therefore the induced contraction could not be ex- 
plained by a reference to any such agency. 
I will now cite some new researches instituted with a view to the discovery of the 
nature of the phenomenon of induced contractions, which is so obscure and at the 
same time so important. 
Observing that the slightest discharges from the jar, inappreciable by the most de- 
licate of our electroscopes, are invariably sufficient to excite violent contractions in 
the frog, it appeared agreeable to analogy to suppose that the cause of induced con- 
tractions might reside in a discharge similar to that of the jar, taking place in the 
muscle in the act of contracting. If that had been the case, it would no longer have 
been a matter of surprise that the galvanometer should give no indication during 
muscular contraction. 
I began my researches by ascertaining whether, by passing very slight discharges 
of the jar through the muscular masses, contraction was excited in the galvanoscopic 
frog, the nerve of which touched the muscle traversed by the discharge. In effect, 
the galvanoscopic frog never fails to contract under the influence of extremely feeble 
discharge, such as are elicited after a very small jar has been discharged two or three 
