GENERAL PHYSIOLOGY OF MUSCLE 



81 



experiment on the heart, on the contrary, there is a negative 

 oscillation in the first phase, which expresses the negativity of 

 the base to the apex at the commencement of systole, and a 

 positive oscillation in the second phase, which expresses the 

 positivity of base to apex at the close of systole and commence- 

 ment of diastole. 



Hermann succeeded in demonstrating the diphasic variation in 



FIG. 58. Distribution of electrical potential to different parts of the human body at the moment 

 at which the diphasic action current of the heart arises. (A. D. Waller.) A, apex ; B, base of 

 ventricles ; 0, equatorial line or plane in which the electrical potential is nil ; a, a, a and 

 b, b, b are the equipotential curves of A and B. 



the muscles of the fore-arm of a man by stimulating the brachial 

 plexus in the axilla. The current was led off by special electrodes, 

 applied one between the middle and upper third of the fore-arm, 

 the other to the wrist or elbow (Fig. 57). 



In the first case there is a descending-ascending, in the second 

 case an ascending-descending diphasic current, as shown by 

 arrows 1, 2 of the diagram. This diphasic action current is the 

 only electrical phenomenon which can be positively demonstrated 

 for skeletal muscle on living man. 



The ascending current in the arm after a voluntary contraction 

 of the muscles (du Bois-Reymond) is not a muscular action 



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