LIVING TORPEDOS IN BERLIN. 465 



The Roman figures are the numbers in order of the electrical 

 nerves, L and R stand for left and right, the rest of the table 

 speaks for itself. It is seen that in these experiments the peri- 

 pheral transverse section shows greater negativity as compared to 

 the equator. Having been struck by this in the two first experi- 

 ments, I thereupon led off the bit of nerve with the clay shields 

 from the two transverse sections. The last column shows how 

 exactly the force so obtained corresponds with the difference of 

 forces between the equator and the two transverse sections. 



In order to test the correctness of the rule thus discovered, I 

 begged Prof. Fritsch to mark one end of the bit of nerve with a 

 thread of coloured silk, and to hand me the portion without telling 

 me which end was central and which peripheral. Without excep- 

 tion I indicated this correctly on the first glance, guided by the 

 ascending direction of the current in the nerve from section to 

 section. Even between symmetrical points of the longitudinal 

 surface in the neighbourhood of transverse sections the ascending 

 current could be observed. It would be important to investigate it 

 in uninjured nerves. 



The first occasion on which this fact was seen was when the 

 Torpedo had been killed, as described on p. 438, by punching out 

 the electrical lobes ; and as I did not arrive at the investigation of 

 the nerves till some time later, there was a possibility that the 

 smaller negativity of the central transverse section as compared 

 with the peripheral might be due to the progressive exhaustion 

 of the nerve. In the fourth Torpedo, which yielded the figures 

 given in the three last rows of the Table, I obviated this sus- 

 picion by not removing the brain. I made instead a sagittal 

 incision with the knife mentioned on p. 440 at some distance from 

 the gills, and immediately after, a second cut through the gills 

 themselves close to the skull. Between these two almost simul- 

 taneous incisions lay the portion of nerve, both transverse sections 

 of which were equally fresh. In this case there could be no ques- 

 tion of the difference being due to exhaustion, and yet the electro- 

 motive difference was as marked as it was regular. Even in a nerve 

 branch detached from the organ, and so distant from the centre 

 that the local exhaustion could not as yet have reached it, I found 

 the ascending current between the two sections. 



Some years ago (1867) I came on traces of a similar law in the 

 sciatic nerve of the frog, but I arrived at no conclusion ; the 

 greater number of my experiments indicated that here the central 



Hh 



