LIVING TORPEDOS IN BERLIN. 441 



bundles of columns do not twitch like muscle, it is not necessary to 

 immobilize them. It is sufficient to make the conducting- troughs, 

 between the clay shields of which the bundle of columns rests on 

 the triangular glass plate, the terminals of the polarising circuit, 

 in order to lead the current in the manner best adapted to the 

 purpose through the ventral and dorsal surfaces to the columns. A 

 couple of non-polarisable conducting tubes serve for the purpose of 

 leading-off the polarisation-current, the clay points of these are in 

 contact with the preparation between the clay shields by which the 

 polarising-current is led in. 



The organ-current then showed itself quite regularly in the 

 galvanometer-circuit just as Matteucci states that he observed it in 

 cubical bits of the organ only 2 mm. wide 1 . This method of 

 observation has the advantage that there can be no suspicion of 

 any electromotive difference between the pigmented skin of the 

 back and the unpigmented skin of the belly. In preparations of 

 tolerably fresh organs the organ-current was always in the direction 

 of the shock. It was easy to demonstrate that a column-like 

 arrangement of the electromotive forces gave rise to it, for it 

 appeared in the same direction no matter where the clay points 

 were applied, and its strength increased with their distance from 

 each other. For example, between the middle and a point of the 

 lateral surface as near as possible to the dorsal end, it amounted to 

 + 13-5 sc. (The plus sign means that the effect took place in the 

 direction of the shock.) Between the middle and a point nearest 

 the ventral end, the amount was + 10 sc. ; but between the two 

 outermost points + 23 sc. That is, owing to the considerable 

 resistance of the conducting tubes, only a little less than the sum 

 of the effects of both halves. In another case the corresponding- 

 numbers were +5, +4, + 1 1 sc. If the connecting line of the 

 clay points cut the axis of the columns vertically no regular effect 

 ensued worthy of being taken into account. 



In these experiments I frequently measured the force of the 

 organ-current and found it to be between 0-005 an ^ 0*013 B*oult, 

 considerably less therefore than the force of the nerve-current in 

 frogs. The current force in bits about 4 cm. long of the organ of 

 Gymnotus, were estimated by Sachs to be from 0-015 ^ 0-030 

 Daniell, the mean therefore being 0-0335. The length of my 

 bundles of columns varied from 29 to 12 mm. according as they 



1 Archives des Sciences physiques et naturelles. Nouvelle Periode, vol. xv. 1862, 

 pp. 41, 42. 



