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344 • ELECTEO-PHYSIOLOGY. 



the galvanometer from tlie lower to the upper extremity of the thigh, and there- 

 fore iu a contrary direction to that which is obtained from the gastrocncmiau or 

 from the entire frog in repose. I have further modified this experiment by 

 forming with a slight incision a transverse section in the upper part of the thigh. 

 In this way there circulates in tlie galvanometer from the first a muscular cur- 

 rent in a contraiy direction to the current of the gastrocncmiau. The experiment 

 is repeated on the thigh, which is made to contract, and as often as several 

 violent contractions occur, the deviation in the galvanometer is seen also to in- 

 crease. In this case the discharge which accompanies the contraction is in the 

 same direction with the current which before circulated iu the galvanometer. 



To these experiments and conclusions there was opposed in Germany a mode 

 of performing the experiment of inducted contraction with the galvanometer, 

 which would have led to a consequence opposed to our own, and by which it 

 was thought the secondary polarity might be avoided. This mode consists in 

 causing the muscle to contract several times and then closing the circuit of the 

 galvanometer. This experiment, which I have often repeated and varied, leads 

 to a result which was to be foreseen from constant observation, and on which I 

 have frequently insisted ; that is, that the electric phenomenon of contraction 

 decreases rapidly with the Aveakening of the contraction, and is in general not 

 produced, except under the strongest contractions, which are the first, and which 

 quickly cease, especially by using a strong inducted current to excite the nerve. 

 The result is, that in such case the circuit is scarcely closed after the first con- 

 tractions have occurred, when the needle makes a slight deviation in a direction 

 opposed to the muscular current, sometimes seems undecided in its movements, 

 and, if the circuit be closed after many contractions, deviates in the direction of 

 the muscular current, but more feebly than with the muscle in repose. 



From all the results which I have cited, as well in operating with the galvan- 

 ometer as with the galvanoscopic frog, I find myself always led to the conclu- 

 sion, at which Cima has also arrived by repeating these experiments upon the 

 higher animals, viz : that in the act of contraction of pertain muscles there is 

 an instantaneous current, or rather discharge, which flows in the "-filvanometer 

 m a contrary direction to the current circulating therein, when the muscles, 

 touched by the extremities of the galvanometer, are in repose. It must be con- 

 fessed, however, that properly to generalize this result, it would be necessary 

 that we should bo able to operate on the muscles of the higher animals in which 

 the muscular irritability ceases with extreme rapidity. 



From this conclusion we do not infer that the electric phenomena of the mus- 

 cle in repose and that of the muscle in contraction have a different origin. 

 Notwithstanding appearances, we have an opposite conviction ; and if there 

 could in experimental science be any advantage in framing hypotheses, we might, 

 by recurring to analogy with well-known electrical apparatus, conceive how it 

 would be practicable, irom the same electro-motor, with a change of form in the 

 various parts of the circuit, to obtain in the galvanometer currents iu opposite 

 directions. But this procedure we are not willing to adopt, and prefer rather to 

 say that we must wait till a true knowledge of the form of the muscular electro- 

 motor is acquired, in order to see this species of anomaly disappear. 



I will conclude this lecture by adducing a new fact of muscular electricity 

 which cleaily lends itself to the .support of the theory we have formed respect- 

 ing the production of this electricity. I prepare from the same frog two half 

 thighs, oppose them to one another, and find by the galvanometer that they are 

 equal. I then cause one of these half thighs to contract several times by irri- 

 tating the nerve which is attached. I quickly thereupon recompose the double 

 battery, and now find a strong differential current in the direction of the muscle 

 left in repose. This current continues a certain time, but constantly decreases, 

 and finally the needle returns to zero. The phenomenon is produced by ncAV 

 contractions, but is naturally less intense, because the contractions become con- 



