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GENERAL PHYSIOLOGY 



poles of the body are stimulated in opposite senses, the anodic to 

 contract, their motion being stronger in the direction of the 

 posterior end, and the kathodic to expand, the motion of these 

 being stronger in the direction of the anterior end, in whatever 

 relation to the direction of the current the body may be fixed 

 (Fig. 202, C). Hence in Amoeba, as in Paramcecium, the making 

 of the current produces at the two poles opposite effects, leading to 

 contraction at the anode and to expansion at the kathode. 



But, in reality, the polar effects of the galvanic current on 

 muscle, as the later researches of Biedermann ('90, 1, 2) on 

 smooth and cross-striated muscles have shown, are more complex 

 than the law of excitation of muscle, in the form in which it has 

 thus far been expressed, declares. The conception of excitation has 

 hitherto been limited to the augmentation of these processes that in 



FIG. 201. Amoeba proteus. At the lef t an unstimulated individual possessing numerous pseudo- 

 podia ; at the right two individuals stimulated by the galvanic current. At the anode a 

 typical contraction is shown, at the kathode a strong expansion ; this is noticed especially 

 clearly upon sudden reversal of the direction of the current. 



contractile substances find their expression in contraction. Ex- 

 pansion (relaxation) has customarily been regarded as a phenom- 

 enon of depression. This is incorrect. By depression is meant a 

 diminution or complete cessation of the vital processes in question, 

 as is exemplified by narcosis. Expansion, however, is based upon 

 an augmentation of processes, just as is contraction. The confound- 

 ing of expansion and depression leads to false ideas. The two con- 

 ceptions should be sharply separated, and the term excitation 

 should be extended to include the augmentation of those processes 

 that in contractile substances find their expression in expansion. 

 From Biedermann's researches it follows that the making of the 

 constant current produces in the muscle not only an excitation of 

 contraction at the kathode, but at the same time an excitation of 

 expansion at the anode. In a muscle that is at the maximum of 

 its extension the excitation at the anode can apparently not find 



