140 
PEOFESSOE MATTErCCl’S ELECTEO-PHTSIOLOGICAL EESEAECHES. 
experiments to which I have just referred, can leave no doubt as to the necessity of gi'^'ing 
another explanation of the effects produced on the galvanometer by a muscle in con- 
traction : when a gastrocnemius or a single entire thigh is in the circuit, M. Du Bois 
Reymond attributes these effects to the secondary polarity of the plates of platinum ; but 
I have clearly proved that the effect is the same when there is no trace of secondary 
polarity. In operating on a thigh, the upper part of which has been cut transversely, 
in which case the current is either null from the neutralization of the two electromotive 
forces, or in an opposite direction to the usual cmrent of the entire thigh, we have seen 
the needle deflect, during the contractions, as in all other cases, indicating that a ciuTent 
is directed in the galvanometer from the inferior to the superior extremity of the muscle. 
According to the principles cited in M. Pouillet’s report, we should have to admit that 
the two currents of this muscle, which are identical and have the same origin, are differ- 
ently modified in the act of contraction, and this would be contrary to all analog}’. 
We are therefore led by the experiments referred to, that is, by stud}’ing the electrical 
phenomena of muscles in contraction with the galvanometer and by the method we have 
described, to the same conclusion as that to which we w’ere led by the researches made 
with the galvanoscopic frog ; namely, that “ a conducting homogeneous arc, the exti-emi- 
ties of which are applied to any two points whatever, at a certain distance from each 
other, of a muscle of a frog, is at the moment of contraction traversed by an electric 
current, or rather discharge, directed from the inferior towards the superior extremity of 
that muscle.” In confirmation of this conclusion, I have only to add the principal residts 
obtained with the galvanoscopic frog. 
Whoever has once seen a piece of living muscle, however small, on which is laid the 
nerve of a galvanoscopic frog, produce the phenomena of induced contraction each time 
that contractions are excited in that muscle by cutting it with a fine pair of scissom. 
cannot but be struck with the analogy which exists between this phenomenon and that 
which occurs, under like circumstances, in a piece of the electric organ of the torpedo. 
In order to study induced contraction with the galvanoscopic fr’og, I proceed as follows : 
— I prepare several galvanoscopic frogs, which are immediately submitted to the passage 
of a weak electrical current in the direction of the ramification of the nerve ; in a few 
seconds these frogs cease to contract, except at the closmg of the cfrcuit, and are there- 
fore fitted to show the existence of a current or electrical discharge only in case that 
current is directed from the nerve to the leg. An assistant has in the meanwhile pre- 
pared from a vigorous frog a thigh, to which is united the lumbar nerve and part of the 
spine. Nerves of several of the galvanoscopic fr’ogs are now stretched in various direc- 
tions over this thigh ; two strips or rolls of paper, 4 or 5 millimetres long, imbibed with 
slightly salt water, are put in contact at one end with the extremities of the thigh, and 
the other ends of these strips of paper are united by two nerves of galvanoscopic fr'ogs. 
turned in an opposite dfrection. The thigh is then made to contract : at fii’st several of 
the galvanoscopic frogs enter into contraction ; but if the experiment is continued, it will 
be seen that contractions take place only in those of the galvanoscopic frogs in contact 
