OF ELECTRICITY IN ANIMALS. 



57 



results as yet incomplete, but which tend to assimilate the 

 electrical with the muscular action. These results are as 

 follow : — 



1. The rapidity of the nervous agent in the electrical nerves 

 of the torpedo seems evidently to be the same as that of the 

 nervous agent producing motion in the frog. 



2. The phenomenon called by Helmholtz lost time exists 

 also in the electric apparatus of the torpedo, and lasts about 

 the same time as in the muscle. 



3. The discharge of the torpedo is not instantaneous, like 

 that of certain kind of tension electrical apparatus, but it 

 is prolonged about fourteen hundredths of a second ; which is, 

 in a remarkable degree equal to the duration of a shock in a 

 frog's muscle. 



We cannot enter here into the details of the experiments 

 which have furnished these results, but we will endeavour, in 

 a few lines, to explain the method which we employed. 



Registering apparatus measure the slightest intervals of 

 time ; this we have seen in speaking of the estimated rapidity 

 of the nervous agent. But, in order to employ the graphic 

 method, we must have motion to give the required signal. 



ThuS: in the experiment of Helmholtz, the muscular shock 

 itself announced that the order of movement which the nerve 

 had to convey^ had arrived at its destination. 



In order to obtain the signal of the electric discharge, we 

 have employed it to excite the muscle of a frog, the shock of 

 which was inscribed on the registering cylinder. 



The trace furnished hy the frog sigjial is somewhat delayed, 

 it is true, after the excitation has been produced ; but this 

 delay is a known quantity, and it can easily be taken into 

 account. 



The following is th(3 method adopted to measure with the 

 ordinary myograph the duration of the different acts which 

 precede the discharge of the torpedo. 



In a preliminary experiment (fig. 12) the nerve of the frog 

 was directly excited, and a note was taken of the time {e g) 

 which elapsed between the instant (e) of the excitation, and 

 the signal {g) given by the frog. 



In a second experiment the torpedo was excited, still at the 

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