io8 



Scientific Proceedings (58). 



1. During descent of the diaphragm, the posterior portions 

 of the heart and the venae cavae descend more than the anterior 

 portion of the base, while the anterior aspects of the apex move 

 forward and as a result often slightly upward. The right and left 

 borders of the ventricle move toward the right. 



2. The movement of the heart to the right does not occur 

 after severing the left phrenic nerves nor upon stimulating the 

 right phrenic nerve. It is, therefore, due to a traction of the left 

 sheath of the pericardium. 



3. A descent of the base of the ventricles, the auricles and 

 venae cavae occurs after the entire pericardium is severed from the 

 diaphragm. Direct experiments show that this is due in part to 

 a traction upon the inferior vena cava making it larger and 

 narrower. 



4. The descent of the base of the heart persists after the vena 

 cava is clamped and divided. This results from a traction upon 

 the ligamentum pulmonale (a double fold continuous with the 

 pleura pulmonalis, and passing downward from the root of the 

 lung to its vertebral and diaphragmatic attachments) which 

 causes the roots of the lungs, the pulmonary vessels and through 

 these the base of the heart to move downwards. 



66 (883) 



Experiments dealing with the relation of the sinus node to the 

 effects of stimulation of the vagus nerves. 



By Alfred E. Cohn. 



[From the Hospital of the Rockefeller Institute for Medical Research, 



New York.] 



Experiments by a number of investigators on the sino-auricular 

 node have warranted the conclusion that this structure is respons- 

 ible for stimulus production and the maintenance of the rate of the 

 heart. Flack thought that this node formed a station in the path- 

 way, both of the vagus and of the accelerator nerves, and that 

 through its agency they exercised their influence on the heart. 

 He attempted to show that exclusion of the node from function 

 consequently interrupted impulses passing over the nerves. 



