PHENOMENA OF MUSCLE AND NERVE. 311 



aperiodic magnet shows this characteristic most plainly by its mode 

 of movement, which does not at all follow the laws which hold for 

 persisting currents 1 , the first part of the deflection being very rapid 

 as compared with the later part, and in the case of light magnets 

 often only a momentary jerk ; evidently the current has perceptibly 

 decreased before the deflection has had time to occur ; hence the 

 deflection is smaller with strongly damped than with slightly 

 damped magnets, apart from the delicacy of the galvanometer. 

 (Compare the above-mentioned experiments with two galvano- 

 meters.) Moreover, the relation of the opposed after-current 

 with the strength and duration of the polarising current is quite 

 of the same kind as in ordinary polarisation 2 . 



As is well known, du Bois-Reymond was the first to indicate that 

 the seat of this ' internal ' polarisation is by no means entirely con- 

 fined to the electrodes of the polarising current, but is spread over 

 the whole led-through region 3 . Since many porous materials, 

 when moistened with electrolytic substances, show an internal 

 polarisation, which may be explained as due to the formation 

 of ions, du Bois-R/eymond applied this explanation to the in- 

 ternal polarisation found in led-through muscle and nerve, these 

 tissues being both porous and electrolytic (du Bois-Reynaond, 

 Sect. 3). 



By experiments with my conducting axis schema, I have demon- 

 strated and explained the phenomenon of internal polarisation, and 

 I have further shown that known physical conditions are effectual for 

 its production in the case both of nerve and of muscle. This former 

 explanation of mine receives now additional support from the fact 

 that it can also be applied to the extrapolar after-currents of nerve 

 and muscle. For brevity I denote by conducting axis schema, a 

 wire enveloped by an electrolytic material, into the envelope of 

 which a current is led, it being indifferent whether the envelope is 

 the twisted thread soaked in fluid used by Matteucci, or the fluid con- 

 tained in a small tube used by myself. A wire thus enveloped in 

 fluid shows, just as muscle and nerve show, opposed polarisation 

 after-currents throughout its intrapolar region 4 . (An exception 

 presents itself when the connection is unpolarisable, such as an 

 amalgamated zinc wire in solution of a zinc salt.) 



1 See du Bois-Reymond on aperiodic magnets. 



2 See Tigerstedt's paper on internal polarisation, p. 80 of this volume. 



3 ' Untersuchungen liber thierische Elektricitat,' i. p. 377 ; ii. 2, p. 378. 



4 See Pfliiger, ' Archiv,' vi. p. 319. 



