466 LIVING TORPEDOS IN BERLIN. 



transverse section was the more negative, the nerve being per- 

 meated from section to section by a descending current. It is 

 obvious that this investigation must be resumed as regards various 

 nerves, both centripetal, centrifugal, and mixed. It will then soon 

 be manifest with what we have to do whether with a peculiarity 

 of electrical nerves, whether with a fundamental law connected with 

 their centrifugal function, or finally, with a less essential difference 

 common to all nerves, dependent only on relations of nutrition. 

 The result seen in the sciatic of the frog, a nerve of mixed function, 

 seems to show that function is not without influence. The last 

 records in the table, of the trigeminus branch, are only in apparent 

 contradiction with this idea, in so far as this branch being a 

 secretory nerve may be also regarded as centrifugally active. On 

 the other hand this experiment seems to show that the greater 

 negativity of the lower transverse section is not peculiar as such to 

 electrical nerves, as indeed was improbable. 



It remains to be asked what connection there is between this and 

 the small electromotive force of the electrical nerves of the Torpedo. 

 The experiment on the trigeminus branch seems to show that this 

 peculiarity in them is not due to their electrical function. Yet it is 

 possible that it is connected with the electrical immunity of the 

 Torpedo and with the high excitatory limen of its muscular nerves, 

 as proved by Boll 1 . Further investigations on this point are 

 necessary. A few experiments made at the same time on the 

 optic nerves of the carp and pike yielded no result worth recording. 



2. Negative variation of the current of the Electrical Nerves of 

 the Torpedo when in a state of activity. 



The nerve marked II in Christiani's experiments above mentioned 

 was in contact with the electrodes by a longitudinal and cross 

 section, and kept the thread at 60 of the scale. By means of the 

 round compensator the thread was brought back to zero. When 

 the nerve was tetanised by means of the inductorium, Christiani 

 obtained a negative variation to the amount of 5 sc., that is, T \ of 

 the original current strength. In another case, in which the nerve 

 had already been used for elect rotonus experiments, the compensated 

 deflection amounted to 120 and the variation to 90 sc., fully of 

 the current strength. When the nerve was divided between the 



1 Untersuchungen, p. 265. 



