188 PROCEEDINGS OF THE AMERICAN ACADEMY. 



be referred to dromotropic intiueuce. With more refined methods of re- 

 cordiug cardiac phenomena, it is extremely probable that the importance 

 of the dromotropic as compared with the chronotropic influence will be 

 found to be still greater than it can now be shown to be. The stimula- 

 tion of the dromotropic fibres of the Vagus causes dissociation in the 

 activity of the different cavities of the heart, affecting the conduction of 

 the contraction wave, not only between auricle and ventricle and be- 

 tween sinus and auricle, but even between the component parts of the 

 sinus itself. The effects upon the conduction between sinus and auricle 

 and between auricle and ventricle are very often in an opposite sense. 



The interference of accelerator and retarding nerves upon the heart, 

 investigated by Bowditch, Ludwig, Baxt, and Hunt, may find its inter- 

 pretation in the dromotropic action of the Vagus. 



In this preliminary notice it seems impracticable to give more details ; 

 the results, with the discussions to which they lead, will be published in 

 full in the " American Journal of Physiology." 



Boston, December 20, 1897. 



