288 PROFESSOR MATTEUCCI’S ELECTRO-PHYSIOLOGICAL RESEARCHES. 
is found invariably to the left of the man. We may account for the position of the 
poles at the extremities of each prism, and the intensity of the discharge being pro- 
portionate with the length of the prisms, by the fact that each prism of the organ is 
a temporary electrical apparatus, as has been proved by numerous experiments. 
3. It is proved by experiments that the strictest analogy exists between the dis- 
charge of electrical fishes and muscular contraction; there is not a circumstance 
which modifies one of these phenomena without acting equally on the other. 
4. The contraction of a muscle developes in the nerve with which it is in contact, 
the cause by means of which the nerve excites contractions in the muscle through 
which it is ramified. Although it has not been possible as yet to decide by experi- 
ment whether this phenomenon ought to be considered as a case of nervous induction, 
or as the proof of an electric discharge produced by muscular contraction, we are 
compelled by analogy to adopt the latter hypothesis. 
5. The electric current modifies the excitability of the nerve which it traverses, in 
a manner which differs greatly according to its direction : the electric current which 
is propagated in the same direction as the ramification of the nerve, destroys its ex- 
citability: the current which is propagated in a direction contrary to that of the 
ramification of the nerve, increases its sensibility: the phenomena excited by the 
cessation of the electric current which traverses the nerves of the animal, are pro- 
duced by the modification which the exeitability of the nerve has undergone by the 
passage of the current according to its direction: the voltaic alternatives are ex- 
plained by the same cause, which is as follows: — the muscular contractions are 
excited by a current whieh is made to pass in a contrary direction to that in which 
its action is nullified. 
After having thus briefly recapitulated the fundamental conclusions which I have 
scrupulously drawn from my lengthened researches in eleetro-physiology, I shall 
begin the exposition of my recent studies on this subject by describing some experi- 
ments the application of which I shall give in the sequel. I wished to satisfy myself 
whether the nervous filaments which conduct an electric current into a liquid, are 
capable, like metallic wires, of acting as electrodes and giving rise to the production 
of electro-chemical decomposition. In order to ascertain this point, I plunged in a 
solution of iodide of potassium two large nervous filaments taken from living animals, 
each of which was separately attached to the metallic extremities of a pile of fifteen 
couples. I did not obtain the slightest trace of electro-chemical decomposition. I 
concluded from this experiment that terminals formed of nervous filaments can- 
not serve to obtain electro-chemical decomposition, which appears to me to demon- 
strate that the conductibility of nervous matter is due to the liquid part of the matter 
itself. 
I studied again the relative conductibility of the muscles to that of the nerves: I 
had already discovered that one might estimate the conductibility of the muscle as 
four times greater than that of the nervous substance. I had also found that a 
