LIVING TOEPEDOS IN BEELIN. 499 



scribed. These springs change the alternating currents of the 

 machine into currents which are all in the same direction, so 

 that seven revolutions per second gave fourteen extra currents in 

 the same direction. Whilst the machine was in motion, its circuit 

 was closed for a shorter or longer period (0^031, o'^ogS, i"-O24) 

 through the organ preparation. When the time of closing was 

 only o"-c>3i, it depended on chance whether an extra current took 

 place exactly in this period, but when it was c/'-c^S, one current 

 must certainly come into action, and two currents might do so. 

 The experiments were made this winter on the fifth fish on the 

 second day, and on the sixth fish in a comparatively fresh condition. 

 The organ preparations showed mostly reversed organ current 

 between the ventral and dorsal skin ; they were taken from the 

 same organs as those preparations of which the one half acted 

 negatively and the other positively (see above, p. 485). The 

 result of the experiments was very unsatisfactory. There was often 

 no action, as was to be expected with the very short period of 

 closing. With homodromous direction of the currents, there was 

 absolutely and relatively positive weak polarisation, and with 

 heterodromous direction, there was much stronger absolutely posi- 

 tive, relatively negative polarisation. Example : 



6. Torp. Fresh. OC- 0-002 7. 2' -P. 



C To" '-031. Cri"o2 4 . 



4 220 1 + 18 4 210 | +60 || 4 430 | ? ; + 10 I 295. 



The primary current was not observed. 



The Saxton machine was succeeded by an ordinary inductorium of 

 a larger kind, and a battery of two large Bunsen chromic acid cells 

 was put into its primary circuit. The spring of the Wagner hammer 

 was removed, and was replaced by the disjunctor described above. 

 This was arranged so as to allow only the opening shocks to pass, 

 but of these, it gave thirty-seven in one second, of which therefore 

 one or two passed the switch in o"-O3i. As far as could be judged 

 from the tension in the secondary circuit, the single shocks by far 

 exceeded those of the Saxton machine. The result was essen- 

 tially the same, no relatively positive heterodromous polarisation 



6. Torp. Fresh. 0(7 + 0-0065. 



I -5oo+*;-37t -'555 +355- 



In the last case, presumably, two shocks passed through. I re- 

 marked as yet in these experiments, nothing of the disturbances 



K k 2, 



