ELECTRO-PHYSIOLOGY. dZO 



Having detained you so loug in describing how exact experiments on the 

 niuscuhir electro-motors are conducted, it will be more easy to explain wilh 

 brevity and distinctness the laws of these electro-motors. 



Any muscle selected in an animal alive or recently killed, may be submitted 

 to experiment either by taking the animal entire and without alteration of the 

 organic "integrity, or after having had its fibres transversely divided. Let us 

 begin with the muscles entire ; and for these experiments the frog, whether from 

 its structure or its tenacity of life, is better suited than any other animal. Hence 

 it is on the muscles of the frog that we shall operate, regard being had, however, 

 to the muscles of other animals in demonstrating the fundamental facts of mus- 

 cular electricity. Whatever may be the entire muscle selected, it will be always 

 terminated at its extremities by the tendinous appendages, which anatomists con- 

 sider as a continuation of the same fibres and which therefore rest on the bases 

 of the muscular fibres. A muscular mass would hence be a fasciculus of cylin- 

 drical fibres on whose bases or tranverse sections the tendinous fibres are estab- 

 lished and form a continuation of them. 



I will not stop to describe all the -experiments which have been deemed 

 necessary suitably to analyze the fiict discovered by Nobili, and to prove that 

 the animal electro-motor does not consist in the assemblage of muscles and of 

 nerves, as has been supposed, nor in the whole mass of muscles of the entire 

 animal, but that, on the other hand, each of the muscles is a distinct electro- 

 motor, whence, by putting an entire frog or other animal in a circuit, all these 

 muscles are made to act at once. The current which is obtained from the entire 

 frog depends, therefore, on the intensity and direction of the various currents 

 with which it is charged. 



In order to make a simple experiment we detach from the entire frog a muscle 

 as entire and intact as possible, such as the gastrocnemius or rather some small 

 muscles of the upper members. With these muscles a battery is readily con- 

 structed by disposing them in series, and then, even with a galvanometer not 

 very delicate, we have the indications of a current which increases with the 

 number of the elements and which is directed like that of the entire frog. In 

 using a battery of gastrocnemian or other muscles it will be seen that the current 

 has always the same direction, either on directly touching with the laminoe of 

 platina the extremities of the muscular battery or interposing wet layers of paper 

 or flannel imbibed with dilierent liquids. If, instead of using gastrocuemians 

 alone, placed in contact with one another, we employ gastrocuemians to which 

 the nervous filament is united we equally obtain indication of the gastrocnemiau 

 current, but they will be much more weak from the great resistance introduced 

 into the circuit'by the nerve. By making the experiment with greater attention, 

 and especially by selecting muscles whose tendinous extremities are as equal 

 as possible, we shall succeed finally in ascertaining what is the most simple form 

 of the muscular electro-motor, and what the law of that electro-motor. 



Suppose that we operate with the very delicate galvanometer, whose extre- 

 mities are those above described — that is, lamintje of amalgamated zinc immersed 

 in the solution of the sulphate of zinc — and that we use the rostra described, 

 either with a simple beak or with cushions of flannel. We place the muscle, 

 which ought to be the great adduc'or mmde, because the experiment succeeds 

 bf'tter, upon gutta-percha, and bring it with its tendinous extremities into contact 

 with the cushions. It rarely occurs that there is no sign of a current, but it is 

 certain that this is much weaker than that which arises from touching first one 

 and then the other tendinous extremity with one of the cushions, and the sur- 

 face or median zone of the muscle with the other cushion. The same result is 

 realized by touching two symmetrical points of the muscle equally distant from 

 the extremities. This fact is constant and general — that is to say, it is verified 

 in all entire muscles, whatever be the animal operated upon, so that the following 

 proposition may be considered as perfectly established by experiment: " What- 



