532 LIVING TORPEDOS IN BERLIN. 



median transverse surface), but are compelled to go round by the 

 edges of the organ. They have therefore to overcome an un- 

 equally greater resistance, and in the same proportion, constitute 

 worse channels of collateral closure, which consequently have less 

 power of weakening the currents which reach the little fish. Thus 

 the insulating character of the organ would tend to increase the 

 action of a conducting and electromotively active column on any 

 part of the external space. The observation that in consequence of 

 the insulating character of the organ the density of the currents 

 flowing round it from the column is increased leads to the same result. 

 This is seen on the right side of the figure, if regard is had to the 

 limitation of the median transverse surface which presents itself 

 as a consequence of insulation. 



The only condition for the legitimacy of these conclusions is, 

 that the resistance of the column should not disappear in comparison 

 with that of external space. This condition in the case of the 

 Torpedo is all the more certainly fulfilled, because, as we saw, 

 the organ even at its best, conducts decidedly worse than sea- 

 water. 



Now the organ is not indeed insulated, but the irreciprocal 

 conduction which we have recognised, performs, as has been already 

 stated, a function similar to complete insulation. The current 

 threads, with the deviation of which into badly conducting channels 

 we are concerned, are all predominantly heterodromous where they 

 meet the organ. Thus they encounter in the organ, a resistance 

 which practically produces the same effect as if the organ were 

 insulated. Each column conducts its own homodromous current 

 comparatively well, but bars the passage to the heterodromous 

 current threads of all the other columns ; and as this is the same 

 for all the columns, the heterodromous current threads are forced 

 to take the circuitous route round the edges of the organ, just as 

 if the organ consisted of a non-conducting substance ; and this 

 remarkable behaviour is the result of irreciprocal conduction. The 

 current of all the columns, and therefore the total current of the 

 organ, increases in density in external space, that is, in physiological 

 effect. 



The increased strength of the shock produced thereby, is at all 

 events more considerable, than that which would have resulted from 

 the insulating property of the fascia covering the organ laterally, 

 which the older investigators imagined to exist, for this would 

 have cut off only the currents between points of the lateral 



