. Electro-physiology. Electrophysiology. IV ELECTROMOTIVE ACTION IN MUSCLE 405 diphasic variation, during spontaneous activity of the mammalian heart, when led off from two points of the ventricle (base and apex). But while in this case the base is at first ahcai/x negative in the frog's heart, corresponding with the invariable direction of the excitatory, or contraction, wave from base to apex—in the mammalian heart (although this is generally the case, as appears from the recent experiments of Bayliss and Starling, 40) there are obvious exceptions, in which, by reversal, either the apex beco
. Electro-physiology. Electrophysiology. IV ELECTROMOTIVE ACTION IN MUSCLE 405 diphasic variation, during spontaneous activity of the mammalian heart, when led off from two points of the ventricle (base and apex). But while in this case the base is at first ahcai/x negative in the frog's heart, corresponding with the invariable direction of the excitatory, or contraction, wave from base to apex—in the mammalian heart (although this is generally the case, as appears from the recent experiments of Bayliss and Starling, 40) there are obvious exceptions, in which, by reversal, either the apex becomes nega- tive earlier than the base (which Waller, , holds to be normal), or there is only a monophasic variation. In this last case there has usually been some _ injury to one of the points led off, by lesion, etc. Bayliss and Starling (} find that it is possible by unequal warm- ing, or cooling, of the ventricle in the spontaneously beating dog's heart, to reverse ^ the direction of the two phasic action currents. It is even sufficient to warm or cool the inspired air. By means of the capillary electrometer j it is possible to show the phasic action current of the heart in the uninjured body of an animal, or man, either by pushing Flo. two fine needle electrodes through the breast-wall into the ventricle, and con- necting these with the electrometer, or by leading off from different points of the body-surface (41). In this case a lead-off from the mouth is equivalent to leading off from the base of the ventricle—a lead-off from the rectum, or from a pos- terior extremity, to leading off from the apex. In addition, the following combina- tions were found (on man) to be favourable for leading-off (cf. Figs. 133 and 134):—. aphic record of action current in mam- malian heart, investigated with the capillary electro- meter. 1. Spontaneous beat of the heart; the first phase corresponds to negativity of apex to base, the second to the reverse action. 2. After i
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