538 LIVING TORPEDOS IN .BERLIN. 



necessary to make the experiment on a Torpedo not divested of its 

 electrical lobes, but it will then be difficult to prevent disturbances 

 arising- from voluntary or reflex shocks 1 . 



I now tetanised the nerves of the first Torpedo, from which the 

 numbers given above were obtained on this occasion, with Helm- 

 holtz' arrangement of the sliding inductorium. The primary coil 

 was filled with rods, and the shocks were led into the nerve by the 

 clay points of the unpolarisable tubes. It was necessary to bring 

 the secondary coil up to 30 mm. in order to obtain a good variation 

 to the amount of 7-1 osc. The variation was observed repeatedly in 

 the same nerve, with descending as well as with ascending direction 

 of excitation, and thus this important gap has been filled up. 



The disturbances which had shown themselves in the correspond- 

 ing experiments of the first communication, now only occurred once. 

 Ewald Hering recently made similar observations on the sciatic 

 nerve of the frog 2 , so that the fact has nothing whatever to do with 

 the function of electrical nerves. It is attributable to the circum- 

 stance, that by the new methods, many minute details can now be 

 recognised in phenomena which were formerly only sketched in 

 outline. When the nerve was replaced by a clay model, there was 

 no such effect on tetanising. 



The next step was to observe electrotonus in the electrical 

 nerves of the same fish. The experiments were conducted precisely 

 as on the first occasion (p. 466). I also now saw anelectrotonic 

 and kathelectrotonic increments spread in both directions, as Prof. 

 Christiani had already done, but I had neglected this observation 

 the first time, because my attention was taken up with disturbances 

 which had hitherto been unexplained, and which presented them- 

 selves to me, as previously to Prof. Christiani. They were now also 

 again noticeable. Electrotonic increments presented themselves in 

 the wrong direction ; after cutting through the nerve, there re- 

 mained actions in the right direction and in considerable strength. 

 The significance of these irregularities must be decided by further 

 experiment. 



1 Very shortly, a paper worked out in the physical department of the Physiological 

 Institute by Dr. M. Mendelssohn will appear in the Archiv fur Physiologie ; the 

 axial current is here traced in different nerves acting wholly centrifugally or centri- 

 petally. 



2 Beitrage zur allgemeinen Nerven- und Muskelphysiologie, 15 Mittheilung. 

 tjber positive Nachschwankung des Nervenstromes nach elektrischer Reizung. In 

 den Wiener Sitzungsberichte, 1884, vol. Ixxxix. p. 137 f. 



