ELECTRO-PHYSIOLOGY CHAP. 



opened after a short closure, diametrically opposed changes of 

 form will be visible in favourable cases in both halves of the 

 muscle. The anodic half shortens, often in no inconsiderable 

 degree, which must obviously be the expression of the break 

 excitation, while at the same time the kathodic half is more 

 plainly relaxed than would presumably have been the case without 

 the intervention of excitation. On rapidly repeating the stimuli, 

 with uniform direction of current, the same phenomena ap- 

 pear, though in diminishing quantity, as at the beginning of 

 the excitation, for as long a period as the muscle remains in any 



FIG. 93. Sartorius fixed in the middle (double myograph). Persistent veratrin contraction. S, 

 closure ; 0, opening of a constant current. Relaxation occurs at the anodic (A), con- 

 traction at the kathodic (K), half of the muscle. 



considerable contraction (Fig. 93). From this it would seem 

 that we are here concerned essentially with local changes in the 

 muscle, confined to the immediate proximity of the physiological 

 anode or kathode, and not, as in cardiac muscle, extending 

 over a larger area. The changes of form described above 

 in the sartorius, thrown by veratrin into an artificial state 

 " analogous to tonus," present a complete analogy with the 

 consequences of electrical excitation in systolically- contracted 

 cardiac muscle, as above described. Here, too, along with the 

 ordinary effects of polar excitation (which for the rest appear less 



