ON THE PROPER CURRENT OP THE FROG. 299 



I had frequently observed, while operating with great rapidity upon rabbits, fowls, 

 and pigeons, that the signs of the proper contractions frequently manifested them- 

 selves, and that therefore the celebrated experiment of Galvani was repeated in warm- 

 blooded animals. When the thighs are cut away from these animals, the nerve laid 

 bare, and folded back upon the leg, contraction is frequently visible. These con- 

 tractions are more constantly obtained by composing piles of these thighs and making 

 the nerve touch the leg. I must say, however, that every time that I have composed 

 a pile of such thighs, I have obtained the signs of the muscular current, for which 

 reason the contractions might have been attributable to that current. 



Let it be remembered, however, that in composing these piles, it is impossible not 

 to put the current which parts from the internal surface of the muscle in circulation, 

 for which reason a pile should be made analogous to that of the half frogs divided at 

 the upper half of the thigh (fig. 6.). Observation has shown, from the time of 

 Galvani, that the points of the leg of the frog to be touched, for the purpose of pro- 

 ducing the proper contraction, are the points of insertion of the surface of the funi- 

 cular tendon of the gemellus or gastrocnemius muscle into the calcaneum. 



In one experiment, described at page 105, I had endeavoured to remove the tendi- 

 nous surface of the muscles of the legs, then composing the pile with the frogs so 

 prepared, I had the current as at first, that is, directed from the feet to the head, in 

 the animal. This experiment, however, did not prove that the proper current exists 

 independently of the tendinous surface of the muscle ; in fact, removing the tendon, 

 I lay bare the muscle, and so doing prepare a muscular pile, in which the current, 

 being directed from the interior to the exterior of the muscle, is therefore in the same 

 direction as the proper current. 



The following are the experiments which led me to generalize the fact of the proper 

 current of the frog. There is no difficulty in preparing the gemellus or gastrocne- 

 mius muscle of the frog, leaving a certain portion of the funicular tendon, or tendo 

 Achillis, which goes on to insert itself into the calcaneum, and taking care to avoid as 

 far as is possible injuring the upper part of the muscle. I prepared a great number of 

 these elements, and arranged them in a pile, as represented in Plate IV. fig. 9, in such 

 a manner that the tendinous extremity came in contact with the belly of the muscle. 

 From this pile I obtained signs of a current directed in the muscle from the tendon 

 to the muscle, that is to say, in the same direction as the proper current. Comparing 

 together an equal number of elements arranged in piles, and consisting of legs alone, 

 or of gastrocnemius muscles only, the intensity of the current has been to all appear- 

 ance the same. 



With equal facility the rectus femoris of the frog may be prepared, leaving the 

 tendinous extremity which is inserted into the patella, and laying bare as little as 

 possible of the internal muscular surface of the upper part. Thus I have been enabled 

 to form a pile composed of several recti femoris, always arranging them in such a 

 manner that the tendinous extremity reposed upon the surface of the muscle as far 



MDCCCXLV. 2 R 



