iv ELECTROMOTIVE ACTION IN MUSCLE 433 



physiological properties of cardiac muscle, Gaskell came to the 

 conclusion that cardiac (and all other) tissue is supplied by two 

 kinds of functionally opposed nerve-fibres, one of which (motor 

 or accelerator nerves) he terms "katabolic," inasmuch as their 

 presumable action is to bring about a destructive change, while 

 the other (inhibitory fibres) he terms " anabolic," because the 

 alterations to which they give rise are of a constructive 

 ( = assirnilatory) character. Just as in accordance with this 

 view " a contraction or an augmentation of muscular energy 

 is a token of disintegration ( = dissimilation), or of the activity 

 of a katabolic or motor nerve, so is relaxation a token of integra- 

 tion ( = assimilation), i.e. of the activity of an anabolic and 

 inhibitory nerve." A similar view was previously put forth by 

 Lowit (61) in connection with Bering's theoretical position. 

 And already before Gaskell's work, experiments had been made 

 (with a negative result, it is true) to determine whether the 

 diastolic vagus - arrest of the heart is accompanied by any 

 particular galvanic effects. Wedenski (62) by means of the 

 telephone, Taljantzeff (63) by means of the capillary electro- 

 meter, investigated the frog's heart during vagus arrest. In 

 the first case there was no sound, in the second case the meniscus 

 did not move, and the absence of any kind of galvanic action 

 seemed a legitimate conclusion. With excitation, such as to 

 produce only a slowing of the heart's beat, and not a complete 

 arrest, Wedenski heard a series of short sounds coinciding 

 with the cardiac rhythm, and corresponding in pitch with the 

 induetorium. But to attribute these to the action of motor 

 fibres of the vagus is a very questionable proceeding. One thing 

 is clear enough it is hardly practicable to devise a convincing 

 experiment upon the possible galvanic effects of vagus excitation, 

 while the normal rhythmic action of the heart persists ; on the 

 other hand, it is no easy matter to obtain a prolonged arrest of 

 the heart without considerable interference with its anatomical 

 and functional connections. Nevertheless Gaskell has succeeded 

 upon the tortoise heart in obtaining a preparation that corre- 

 sponds with an ordinary nerve-muscle preparation in that the 

 muscle is at rest the nerve, on the other hand, being an in- 

 hibitory nerve. In the tortoise and the crocodile a particular 

 nerve (the " coronary nerve ") runs alongside of one of the 

 coronary veins, from the sinus venosus to the aortic bifurcation. 



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