334 ELECTRO-PHYSIOLOGY CHAP. 



in the discharge of spurious break twitches by internal shunting 

 of the demarcation current, is that the kathodic points of fibres 

 in immediate juxtaposition with the electromotive surface, by 

 which current leaves the muscle, become temporarily the points of 

 entrance of an adequate galvanic current (in which case there will 

 only be partial compensation of the demarcation current), it might 

 be expected that spurious break twitches would appear, not only 

 as in the case described above on applying " atterminal " 

 battery currents, but also when, on "abterminal" passage of current 

 through the entire muscle or a portion of the same, the entry of 

 the current occurs at the limit of an artificial cross-section in 

 the region where the muscle current leaves it. It is in fact 

 sufficient, for the discharge of spurious break twitches of great 

 vigour, to make an artificial section at the pelvic end of a 

 sartorius, followed immediately by a weak descending galvanic 

 current through the entire muscle, entering laterally close under 

 the margin of dead and living substance by means of a thread 

 electrode. 



If further, with abterminal direction of current, the dead ends 

 of fibres are conceived as connected by any kind of conductor 

 with the zone of normal longitudinal muscle -surface imping- 

 ing on the border, we might expect spurious opening effects of 

 excitation in this case also. Such, e.g., do appear when one end 

 of the muscle is crushed with small forceps ; the bulging and 

 curving of the longitudinal surface of the fibres then give repeated 

 opportunities to both muscle current and battery current to enter 

 and leave at points in the uninjured surface of the muscle, and 

 thus to discharge effective make, or spurious break, excitations. 

 If, after ascertaining that an ascending current of medium intensity 

 discharges no perceptible break excitation in a sartorius stretched 

 in the double myograph, the muscle is crushed, as indicated, close 

 to the lower end of the tendon, opening twitches will appear 

 almost uniformly direction, intensity, and duration of closure of 

 the exciting current remaining constant and must, according to 

 the above, be regarded as spurious (Biedermann, 6 ; Engel- 

 mann, 7). 



From this digression we may return to the consideration of 

 the " current of rest " in muscle, its properties and its origin. 

 Since, provided the galvanometer swings are not excessive, the 

 deflections are known to be proportional to the intensity of the 



