MUSCLES, NERVES, AND ELECTRICAL ORGANS. 203 



increment' (compare Sect. I9) 1 . After what I have just said about 

 nerve polarisation, however, positive polarisation in FleischPs experi- 

 ment must exceed negative to a considerably greater degree in the 

 case of the opening- than in the case of the closing- shock, and the 

 possibility that this participated in the result is at least to be borne 

 in mind. 



If the negative polarisation does not spread beyond the poles 

 (which I do not as yet consider proved), while positive polarisation 

 does so (which I, for my own part, never regarded as demonstrated), 

 we might perhaps believe that the extrapolar positive polarisa- 

 tion exceeded the similar intrapolar to some considerable extent. 

 But I have no intention of entering now on a discussion of these 

 obscure and complicated questions. 



In so far as the extrapolar electrotonus currents outlast the 

 opening of the polarising current, the intrapolarisation being 

 however necessarily present during the closing of the battery, one 

 sees that the distinction between the second and third of the 

 different classes of electromotive phenomena in muscle and nerve 

 referred to in Sect. 2, disappears, and it would be better to distin- 

 guish only two classes, that of the independent or primary, and 

 that of the secondary phenomena, by including under the latter, 

 without reference to the time of their appearance, all the phenomena 

 an extraneous current generates as a current, and not merely as 

 an irritant in muscle and nerve. 



16. Tigerstedt's Experiments on Nerve Polarisation. 



Last year Tigerstedt of Stockholm described some experiments 

 on internal polarisation of nerves 2 . For certain reasons he led off 

 the after-current through the same electrodes which had led in the 

 polarising current. He used no stronger battery than three 

 Meidingers. He regulated the time of closure with the hand, 

 according to the metronome : the shortest amounted to i", the 

 longest to 240". The transmission time was determined by means 

 of the Marcel Deprez's electromagnetic marker and varied between 

 o"-o2 and o"-O4. 



Tigerstedt also obtained only negative polarisation. He formu- 

 lated his results as follows: ' I. With a current up to three Mei- 

 dinger cells the polarisation is almost directly proportional to the 



1 Pfliiger's Archiv, 1879, v l- ^ x - P- 4 J 6- 



2 See Tigerstedt's paper on Internal Polarisation, p. 77 of this volume. 



