454 ELECTRO-PHYSIOLOGY CHAP. 



The category of secondary electromotive phenomena is not 

 completed with the admission of positive anodic and negative 

 kathodic polarisation in striated muscle. In view of the strik- 

 ing polar inhibitory effects exhibited under certain conditions, 

 not merely in tonic-ally contracted smooth, but also in striated 

 muscles under the influence of the battery current, it is 

 evident that the effects of electrical excitation of such a muscle 

 must, in regard to secondary electromotive phenomena, express 

 themselves sometimes under given conditions as positive 

 kathodic, or negative anodic, after-currents. And, in reality, if a 

 muscle with parallel fibres is conceived as uniformly excited 

 (contracted) in all its parts, it will be as ineffective in external 

 electromotive response as in the wholly uninjured state ; if it is 

 then traversed longitudinally by current, relaxation occurs 

 during closure at the anode, due to quelling of the existing 

 excitation, while at the kathode there will subsequently be an 

 increase of contraction. On opening the circuit everything is 

 reversed, and the inhibition is localised at the kathode. Then, if 

 we picture the corresponding end of the muscle as connected with 

 the centre by a leading-off circuit, current would flow in the 

 same from end to middle in the muscle therefore in the reverse 

 direction, i.e. in that of the polarisation current, i.e. positive 

 (70). 



Just as the polar inhibition of contraction is best exhibited in 

 veratrin poisoning, it is easy by the same method to investigate 

 the galvanic changes produced by the electrical current in a strip 

 of muscle, alternately resting and excited. Instead of poisoning 

 the whole muscle with veratrin, it appears in this case better to 

 apply it to one end of the sartorius only. Each momentary 

 excitation will then, as has already been pointed out, induce pro- 

 nounced and tolerably protracted negativity of the poisoned strip. 

 If the lower end of the sartorius is taken, and closure of a de- 

 scending battery current (2 Dan.) effected for a short time (1- 

 4 sees.), after rapidly compensating the veratrin action-current 

 developed by a brief excitation, there follows without exception a 

 more or less considerable swing back in the direction of a homodro- 

 mous, i.e. positive, after-current corresponding with a passing or 

 l>i'rmancnt diminution of negativity of the kathodic ends of fibres. 

 If the period of closure is protracted ever so little, the effect soon 

 passes into its contrary, or at any rate becomes diphasic (positive, 



