452 



THE DYNAMICS OF CARDIAC ACTION. 



in the neck, the effect is very different from that just described, 

 for the beats are increased in frequency, though they may at 

 first be diminished in force. And, occasionally, the beats are 

 increased both in force and frequency; the result is augmenta- 

 tion, not inhibition." 



This suggests that confusion must inevitably reign when 

 it becomes necessary to clinically determine the meaning of 

 danger-signals, but if the tendency of the adrenals to strengthen 

 and reduce the pulse-rate, while that of the vagus under ex- 

 cessive oxidation is to quid-en it, is borne in mind, and, fur- 

 thermore, that weakness of the heart-stroke portrays correspond- 

 ing weakness of suprarenal activity, no confusion need exist. 

 Of course, all this rests upon our assertion that oxidation proc- 

 esses when enhanced by overactivity of the adrenals correspond- 

 ingly increase the heart-beats. That such is the case may be 

 illustrated by the following sentence of Professor Wood's in his 

 section on the physiological action of quinine: "Jerusalimsky 

 attributes the increase of the pulse-rate to paralysis of the 

 inhibitory apparatus: a view which is supported by the asser- 

 tion of Cerna that previous section of the pneumogastric pre- 

 vents the quickening of the pulse-rate." Our interpretation 

 of the functions of the vagus does not, of course, harmonize 

 with the words "paralysis of the inhibitory apparatus," since a 

 far less complicated process inordinate activity of the vagal 

 functions accounts, according to our view, for the occurrence 

 of inhibition. Furthermore, we look upon this phenomenon 

 as pathological and absolutely removed from the physiological 

 purposes that the words "inhibitory apparatus" imply: a feature 

 which necessarily emphasizes our belief that no such apparatus 

 exists. Briefly, the phenomenon generally recognized under 

 the term "inhibition" appears to us to be accounted for in the 

 following deductions: 



1. No cardiac inhibitory apparatus exists as a physiological 

 entity. 



2. Active inhibition of the heart may be caused ~by excessive 

 stimulation of the vagus. 



3. Passive inhibition of the heart is primarily due to insuffi- 

 ciency of the adrenals. 



The reasons for this are embodied in the following general 



