ELECTRICAL FISHES 



437 



stimulation) shows that the discharge from the organ quickly 

 reaches its maximum after the period of latency, which maximum, 

 unlike the latent period, is higher in large vigorous specimens 

 (curve a) than in small animals (curve &). It declines much 

 more slowly, passing gradually into an after-effect in the 

 direction of the discharge, which may last for minutes after a 

 single brief stimulus. The duration of shock is, in round numbers, 

 0'04-0'06" on exciting a lively fish with break induction shocks 

 at room temperature. Schonlein determined the period of 

 discharge at 0*008" or less, a value that agrees with Gotch's 

 figures for the direct total excitation of a bundle of prisms. 



Jolyet, in his time-measurements, occasionally observed a rise 

 and fall of the discharge in the organ, on stimulating the nerve 

 with a single induction shock, which he referred to temporal 

 differences in the commencement of discharge in different parts 

 of the organ. Gotch obtained the same effect subjectively on 

 dividing the nerve of an organ -preparation held between the 

 fingers, with a rapid scissors' cut. The oscillatory form of the 

 curve of discharge, with several (even 4) apices, can then be 

 detected unmistakably with the spring rheotome after each single 

 stimulus, both on larger strips of organ, and on bundles of a few 

 prisms only. The following table gives the results of such a 

 series of experiments, and shows that at about Ytnr" a ^er the 

 first maximum of the discharge there is a second weaker and 

 (after another xcro") even a third still weaker maximum : 



I. Max. 



II. MJ 



III. Max. 



These results are even more apparent from the schema in Fig. 277. 



