. 



LIVING TORPEDOS IN BERLIN. 481 



about these questions also, according to the position of the subject 

 at the present moment, because the scantiness of material and the 

 uncertainty of its condition compel me to deviate in this case from 

 the rule which I always strove to observe in treating- of muscles 

 and nerves, viz. to publish investigations, only when they had been 

 completed according to the best of my knowledge and power. 



The preparations for the experiments were the same as in those of 

 the first communication. The animals were killed in all cases in 

 the way described there (p. 438), by punching out the electrical 

 lobe of the brain with a single blow of a hammer. This operation 

 presents no difficulty to any one who studies Savi's drawing * closely, 

 even though he be not so conversant as Prof. Fritsch with the 

 anatomy of the torpedo. It is advisable to make a slit in the 

 sagittal plane in the skin first of all, as it easily slips laterally from 

 under the borer and takes the rod with it, so that the sagittal plane 

 does not divide the hole in half. The fish never gives a shock after 

 removal of the lobes, even if this has not been accomplished fault- 

 lessly, but it can still wriggle for a long time as well as perform 

 reflex movements. Any part of the organs not used on the day 

 when the fish was killed was kept on ice in hot weather. 



Perhaps it is not useless to remark that the polarisation reverser 

 with its time disks 2 regulating the duration of a polarising current, 

 which I have used for many years as well as in the present experi- 

 ments, is to be found described and figured 3 in the concluding part of 

 my * Untersuchungen iiber thierische Elektricitat' recently published. 

 My investigations on polarisation at the junctions of dissimilar 

 electrolytes and in the interior of moist, porous semi-conductors 

 are also communicated there in full ; these form one of the most 

 important foundations for all researches on electromotive tissues, but 

 until now only extracts had appeared in the first volume of the 

 ' Gesammelte Abhandlungen.' 



2. On the electromotive behaviour of the skin of Electrical 



Fishes. 



I have sought in vain, in organ preparations of Malapterurus 



1 Matteucci, Traitd des Phe'nomenes electro-physiologiques des Animaux. Paris, 

 1844, Planche I. 



2 Gesammelte Abhandlungen, etc., vol. i. pp. 3, 13, 34; vol. ii. p. 718. 



3 Loc. cit, vol. ii. Part ii. Berlin, G-. Keimer, 1884, pp. 389-395, Plate vi. Figs. 151, 

 152, A, B. The means by which I can insure that a polarising or tetanising current 

 shall last for small fractions of a second only, are not yet given here ; this will be 

 done at the first opportunity. 



I i 



