LIVING TORPEDOS IN BERLIN. 501 



initial position of the switch, and the other, that position at which 

 the clay points just touch the preparation. 



I convinced myself of course beforehand, that the passage of the 

 shock would not produce any perceptible effect on the galvano- 

 meter, by using a clay model in place of the preparation ; only 

 a trace of negative polarisation could be perceived in the clay. I 

 then compensated any organ current which might appear when the 

 points were placed on the actual preparation, so that no deflection 

 of any importance ensued when the points were replaced after they 

 had been removed. The sparks in the primary circuit were 

 diminished by Fizeau's condensator. The conducting wires of the 

 secondary coil and beyond it consisted of wires covered with gutta- 

 percha throughout. The number of turns was 53 an ^ the dis- 

 tance from the galvanometer was zero. 



In spite of the risks connected with such considerable movements 

 of electricity in the neighbourhood of a sensitive galvanometer, the 

 experiment proceeded without any disturbance. It was made first 

 on the torpedo which had been kept in the aquarium since October. 

 It gave shocks only when it was strongly excited. But the pre- 

 parations still showed an adequate organ current. The result of the 

 experiment was again negative. I did not succeed in obtaining rela- 

 tively positive polarisation by the heterodromous opening shock of 

 the inductorium, the observed polarisation being relatively negative, 

 absolutely positive. But since the homodromous shock only gave 

 weak and relatively negative polarisation, it was evident that the 

 functional activity of the organ was not sufficiently good for the pur- 

 pose, and that the experiment ought to be repeated with a fresh 

 fish. 



This was effected a short time afterwards with the eighth 

 torpedo, which arrived only in the spring, and which was in a 

 comparatively good condition. But the result remained essentially 

 the same. The homodromous shock now produced absolutely and 

 relatively positive polarisation far beyond the limits of the scale, 

 and the heterodromous absolutely positive, relatively negative 

 polarisation extending also beyond the limits ; effects in the same 

 direction which disappeared very gradually were left behind. In the 

 same measure as the functional activity decreased on more frequent 

 repetition of the experiment, the intensity of the phenomena also 

 diminished, until the ordinary type returned, viz. absolutely and 

 relatively positive deflections due to the homodromous induction 

 currents, and relatively negative, absolutely positive deflections due 



