774 Experiments 



the highest points at 6.7 cm., or a pressure of 13.4 cm., so that the 

 amount of the respiratory oscillation is 2.4 cm., and the average pres- 

 sure L2.2 cm. 



The animal is then placed in the compression apparatus, and a 

 pressure of +53 cm. is reached in 45 minutes. Then we obtained with 

 the same artery the tracing in Figure 70; low pressure 12 cm.; high 

 pressure 15.6 cm.; average 13.8 cm.; amount of oscillation 3.6 cm. 



Fig. 71 — Tension of the blood in the carotid artery. Normal pressure. 



Fig. 72 — Tension of the blood in the carotid artery. Compressed air. 



Fig. 73 — Tension of the blood in the carotid artery. Normal pressure. 



The pulse rate dropped from about 216 to 200, and the respiratory 

 rate from 41 to 29 per minute. 



Experiment CCCXXXVI. February 23. Large dog, new subject, 

 strong, in which a subcutaneous injection of 10 eg. of chlorhydrate 

 of morphine had been made to quiet its constant struggling. It slept 

 during the entire experiment. 



At normal pressure we obtained the tracing of Figure 71 from a 

 carotid artery. 



After the doors had been closed and the pressure raised in three 

 quarters of an hour to 53 cm., we got the tracing in Figure 72. 



Finally, after return to normal pressure in 5 minutes, we traced 

 Figure 73. 



