430 LIVING TOKPEDOS IN BERLIN. 



the most positive and the most negative spots in each organ after 

 the separation would assume a position intermediate between the 

 median edge and the middle, which last would only be reached 

 if the organs were placed at such an indefinite distance from each 

 other that each could be regarded as alone existent. 



Thus it is clear that even apart from the diminution in the 

 height of the columns towards the sides, currents would exist on 

 the back and belly of the Torpedo in the direction observed. The 

 thinning of the organ towards the sides would nevertheless have 

 the effect first of strengthening these currents, and secondly of 

 shifting the points of greater and lesser positivity and negativity 

 to the median borders of the organ. It would also appear that 

 differences of tension due to inclination-currents similar to those 

 observed by me in oblique sections of muscle, would act in the 

 same direction 1 . Another conclusion may be drawn from all this 

 which is especially important to me at the point at which I have 

 arrived. The median borders of the organ being the most positive 

 dorsally and the most negative ventrally, they must necessarily 

 be relatively more positive and more negative than the middle line. 

 So that there must be currents on the back from the borders towards 

 this line, on the belly from the latter to the former. Colladon's 

 second proposition and Matteucci's statement that the points of 

 nerve entrance on the back and belly are relatively the most 

 positive and the most negative (see p. 428), might appear to 

 imply that the authors had actually observed the state of things 

 indicated above. But it is unlikely that the means at their 

 disposal were sufficient, or that they would not expressly have 

 mentioned an observation so remarkable. However this may be, 

 the result will show that it was worth while to put our conclusions 

 on this matter to the test of experiment; and for many years 

 I waited a suitable opportunity of doing so 2 . 



A Torpedo 29 cm. long was placed on its belly in a vessel filled 

 with just enough sea water to cover the back of the animal. The 

 following arrangement was used to lead off" the shocks into the 

 experimental circuit. Two amalgamated zinc plates, each 10 cms. 

 long and 3-5 broad, enclosed in corks, could be placed in every 

 position and at any desired distance in the manner described by 

 Norremberg 3 . Oblong pads 4 of equal breadth with the plates were 

 connected with them; they were soaked with sulphate of zinc 



1 Gesammelte Abhandlungen, vol. ii. pp. 93-127. 



2 Loc. cit. p. 690. 3 Loc. cit. p. 648. * Loc. cit. vol. i. p. 7. 



