Vagus Currents Examined with the String Galvanometer 245 



and Breuer ^ on the self-regulation of tlie respiratory movements obtains 

 in this way fresh support. 



The connection of the respiratory and the heart-beat undulations in the 

 electrovagogi-am also throws light on the association which virtually exists 

 between the heart's action and the respiratory movements. This associa- 

 tion finds inter alia its expression in the constant ratio between the 

 number of respiratory movements and the number of heart-beats per 

 minute. It is well known that this ratio usually remains unaltered with 

 variations in pulse frequency. Since we now learn that the beating heart 

 sends rhythmic stimulations along the vagus to its centre, we may 

 reasonably ask whether these stimulations may not reach the respiratory 

 centre and there cause with each variation of the pulse frequency a 

 proportional variation of the frequency of the respiratory movements. 

 In this way an automatic regulation of the respiratory movements would 

 be promoted by the heart's action. 



Yet another automatic regulation may be pointed out, viz. that of the 

 heart's action by itself. We must in all probability look to this regulation 

 as furnishing the cause of the vagal tonus, this tonus being thus maintained 

 automatically by the action of the heart itself.- 



• J. Breuer, ibid., Bd. Iviii., S. 909, 1868. 



- A more detailed description of our experiment.-^ will appear in Pfliiger'.s Archiv f. d. 

 ges. Physiol. 



