460 LIVING TORPEDOS IN BERLIN. 



which absolutely positive polarisation may be indirectly affected by 

 the homodromous current but not by the heterodromous, attributes 

 a new and obscure property to the organ. Indeed the first inter- 

 pretation has something of a similar character in so far as it is 

 assumed that only the homodromous current liberates the shock. 

 But we can account for the same series of phenomena which Fig. 1 7 

 was intended to illustrate, if we admit that a shock may be gene- 

 rated by the heterodromous current along with relatively negative 

 and absolutely positive polarisation. It must indeed remain much 

 weaker than that through the homodromous current, but for this 

 the law of contraction offers an analogy. 



So much doubt, however, is attached to the first explanation that 

 I cannot unreservedly agree to it. It is to be remarked besides 

 that it rests upon a supposition which we made on account of its 

 simplicity, but which is still unproved, namely, that the hetero- 

 dromous current is incapable of generating relatively positive 

 polarisation. All that is certain is that such polarisation has not 

 yet been seen, but it may have been constantly masked by rela- 

 tively negative polarisation, because weaker than the homodromous 

 absolutely and relatively positive. This is indeed the conception 

 which lies at the base of our construction in Fig. 1 7. 



Thus it is by no means so certain that there may not be two 

 conditions, both connected with the pile-like arrangement of the 

 molecules, which are the same in their external effect, but different 

 as regards what happens in the interior of the electrical plate, one 

 corresponding to the shock, the other to absolutely positive 

 homodromous polarisation. The organ-current no less than the 

 after-effect of the shock, according to the first assumption, demon- 

 strates that every absolutely positive effect is not a shock. 



It sometimes comes about, however, in series of experiments with 

 fresh preparations that at first an action follows so exceptionally 

 strong that the scale shoots out of sight, and in this the after- 

 effect of a shock, if not the last portion of one, may undoubtedly be 

 recognised. This phenomenon presents quite a different aspect from 

 the ordinary absolutely positive polarisation which is experienced 

 when observations are frequently repeated on the same preparation, 

 inasmuch as it does not show a persistence proportional to its 

 original strength. A similar succession of phenomena are observed 

 in the after-effects of shocks liberated by mediate excitation of the 

 preparation such as cutting off protruding ends of nerve trunks. 

 The way in which the absolutely positive deflections gradually and 



