Scientific Proceedings (121). 



The heart seemed to be more easily thrown into fibrillation 

 in the animals which had been cooled than in correspondingly 

 prepared animals at normal body temperature. Death in most 

 of the experiments on cooling was due to fibrillation of the heart. 



Influence of Temporary Asphyxia. — In dogs with the thoracic 

 aorta ligated repeated stimulations of the vagus are followed by 

 rapid failure of gastric response to stimulation. Allowing the 

 blood to pass again to the stomach is followed by recovery of the 

 gastric response to vagus stimulation. 



These experiments would seem to indicate that in the dog as 

 well as in the turtle a complex neuro-muscular mechanism in- 

 fluences the effects of vagus stimulation on the stomach. This 

 mechanism in the dog is very sensitive to partial asphyxia. It 

 may be in the turtle that the rapid failure of gastric response to 

 vagus stimulation is dependent on circulatory changes causing 

 an asphyxia of the complex neuro-muscular mechanism. 



Summary. 



1. In the dog stimulations of the vagus repeated at short 

 intervals are followed by contractions of the stomach of approxi- 

 mately uniform amplitude. 



2. Prolonged stimulation of the vagus is followed by a single 

 contraction of the stomach and its usual subsequent relaxation in 

 spite of continued stimulation. Failure of cardiac inhibition 

 occurs at about the same time as relaxation of the stomach begins. 



3. Reduction of the body temperature to 25 0 C. to 23 0 C. is 

 followed by decreased response to vagus stimulation but no indica- 

 tions of either failure of gastric response to repeated vagus stimula- 

 tion or tetanus. At 21 0 C. vagus stimulation is without effect on 

 the stomach but stimulation of the stomach wall is followed by a 

 contraction. 



4. Partial asphyxia of the stomach by shutting off the blood 

 supply to the part is followed by rapid failure of gastric response to 

 repeated vagus stimulations similar to that observed in the turtle. 

 Removal of the asphyxia is followed by recovery of the gastric 

 response to stimulation. 



