PHENOMENA OF MUSCLE AND NEKVE. 319 



practicable, as everyone versed in the mathematical laws of the 

 subject will admit, since for its expression it would be first of all 

 necessary to state the distribution of polarisation upon the surface 

 of the core at the moment of break. This distribution, however, 

 changes with the very currents which tend to equalise matters, and 

 these currents themselves vary under the influence of the resistance 

 of the gaseous ions. The principal points are, I believe, sufficiently 

 explained by the foregoing experiments and theoretical considera- 

 tions, I therefore refrain from giving the approximate distribution 

 charts which I have prepared of the chief cases. 



Let us now go back to muscle and nerve and see what polarisa- 

 tion after-currents are to be expected in these tissues. 



The polarisable combination of core and envelope in muscle and 

 nerve is, as I have previously shown *, a ' doubly polarisable ' one. 

 We infer this 



(i) From the approximately equal size of the electrotonic current 

 branches in the anodal and kathodal regions. 



(3) From the existence of two separate oppositely polarised 

 regions, with intermediate indifference-point, as testified to by the 

 well-known excitation phenomena of an- and catelectrotonus. 



The envelope may be regarded as very thin, the conductivity of 

 the core as in no way relatively great. Without doubt, therefore, 

 with these tissues the state of matters is this, that the polarisation 

 bipolar after-current does not spread into the extrapolar regions. 

 So that these only show the idiopolar after-current as in the case 

 of the platinum wire schema with thin fluid envelope. 



The polarisation after-current in muscle and nerve must therefore 

 be (opposed to polarising -current) in the intrapolar, + in the extra- 

 polar region. 



J3. The after-currents proceeding from the break-excitation. 



A number of facts have established that it is the anelectrotonic 

 region which is excited both in muscle and nerve at the moment 

 of break, and that this region may remain in prolonged excita- 

 tion on the break of a very strong current or one of long duration. 

 Notably, Pfliiger has shown, by a beautiful experiment, the con- 

 nection of Bitter's breaking tetanus in nerve with the excitation 

 produced by a disappearing anelectrotonic state ; in muscle, indeed, 



1 See Pfliiger, Archiv,' vols. v., vi., vii. 



