ON LIVING MALAPTEKUBUS. 387 



removal of the fish from the trough to the experimental tub and 

 back again, it was excited eleven to fourteen times ; however, it 

 gave at least twice or thrice as many shocks. In the course 

 of such a series of experiments, the fish became evidently fatigued. 

 It became pale (see above, p. 375), and at last responded with one 

 discharge only when the cover was put on. In certain respects this 

 was advantageous ; it could not, however, be depended on, as the 

 fish not unfrequently grew impatient towards the end of the series, 

 and unexpectedly gave several exceedingly strong shocks following 

 each other rapidly. 



One difficulty of experiments with Malapterurus in the form 

 which I gave to them, lies in the necessity for three observers 

 one to manipulate the fish, one to sit at the telescope, and one to 

 watch the frog-interrupter. I take this opportunity to express my 

 tardy, but not less hearty thanks to Messrs. Pfliiger, G, Quincke, 

 and Rosenthal, who gave me their assistance at that time. 



5. Subjective testing of the shock of the Malapterurus. 



In comparison with its size, the shock of Malapterurus is sur- 

 prisingly violent. If the head and tail of a powerful fish are 

 touched with the fore-fingers in the water, the shock does not 

 extend beyond the knuckles. If it is seized with hands thoroughly 

 wetted, a severe shock is received up to the elbow. If it is touched 

 with one hand, a pricking sensation is experienced in the skin, 

 a burning one in wounds, and a painful shock is felt in all the 

 joints of the submerged parts. The best way to take the shock' is 

 to hold with wet hands, ordinary metal handles which are connected 

 by long wires with the linings of a leading-off cover, and to let an 

 assistant put this on the fish. As one is accustomed to test electric 

 shocks in this way, and is not disturbed by anxiety to get proper 

 hold of the fish without hurting it, or by the feeling of repulsion at 

 laying hold of it, one can better judge of the sensation caused by 

 the shock. The shock does not seem so sharp as that of a Leyden 

 jar, but has a somewhat swelling character. Several maxima may 

 be frequently distinguished in it. By sending opening shocks of 

 an induction apparatus, with two Groves in the primary circuit, 

 through the water of an experimental tub, by means of copper 

 plates plunged into it, having first approximated the secondary 

 coil to the primary as closely as possible, the shock which I ex- 

 perienced when my hands were immersed in the water, was certainly 



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