434 LIVING TORPEDOS IN BERLIN. 



curves do not merely stream out from the so-called polar surfaces, 

 but also cut the lateral surfaces of the organ 1 . They then run 

 inward and outward through the body of the fish and occupy the 

 surrounding space. The curves do not, however, as represented by 

 Cavendish, start from the polar surfaces of the columns as pro- 

 longations of their axes. But the curves in this direction, according 

 to the principle of the superposition of currents, blend with the 

 curves which tend from the thicker to the thinner portions of the 

 organ and through the latter to the ventral surface. Hence it 

 arises that the resulting curves are inclined towards the sides, as 

 shown in the figure. A circumstance occurs here with which I 

 had previously to deal in my 'Experimental criticism of the dis- 

 charge hypothesis.' A nerve end-plate, regarded as an electrical 

 plate, which therefore has a stronger electromotive force the thicker 

 it is, and which becomes thinner from the middle towards the 

 edge, resembles the Torpedo organ, which in like manner decreases 

 towards the sides. Here, therefore, if there are really nerve end- 

 plates in this sense, the curves of the current must stream obliquely 

 out of the one surface and into the other 2 . If you imagine a 

 sagittal section through a Torpedo organ, there being from front to 

 back no diminution in the height of the columns comparable with 

 that in the transverse direction, the direction of the curves in the 

 sagittal plane would be primarily that of the columns. The whole 

 system of curves could only be made clear by means of a model. 



The inclination outwards of the median columns shown in the 

 figure (their electromotive action being parallel to their axes) must 

 influence the direction of the current curves on the back in the 

 same way as the greater height of the median columns, whereas on 

 the belly, as indicated in the figure, the inclination of the curves is 

 lessened by the same circumstance. The oblique position of the 

 columns is more strikingly seen in the drawing of the cross section 

 of a young Torpedo given by Fritsch in the Memoir alluded to on 

 p. 419. By this means the region over the middle of the fish is 

 apparently deprived of denser current curves and, to use a military 

 expression, becomes comparable to a dead angle (zu einem todten 

 Winkel). The teleological signification of this arrangement is 

 obscure, for when the fish, in its favourite position, lies half buried 

 at the bottom of the sea, the dorsal surface seems to require the 

 greatest protection, while the ventral surface is not in need of any. 



1 Gesammelte Abhandltmgen, vol. ii. pp. 629, 682. Untersuchungen, p. 148. 

 8 Ibid. vol. ii. p. 708, Fig. 47. 



