38 



Dr. C. Bolton. Physiological Action of a [Mar. 20 ; 



Inspiratory gasps continued for from two to three minutes after the heart 

 had stopped. 



Stimulation of the Vagi. — The vagi were stimulated 10 times, commencing 

 just when the blood-pressure curve was starting on its rise to the maximum 

 point and ending about two minutes before the heart stopped. On each 

 occasion there was no effect whatever upon the blood-pressure curve or upon 

 the heart beats. 



Experiment 11. — Eabbit, weight 2210 grammes, poison 1/20 gramme 

 (= 0'022 gramme per kilogramme). Both the vagi were divided before the 

 poison was injected. 



Blood Pressure. — The blood pressure rose from 124 to 130 mm. Hg to 

 a maximum height of 168 to 170 mm. Hg during the 39 seconds after the 

 poison was injected. Death occurred 84 seconds later. 



Stimulation of Vagus. — The left vagus was stimulated (strength 10) just 

 as the pressure Curve reached its maximum height, but no effect was 

 produced on the blood pressure. The vagus was again stimulated as the 

 blood pressure was falling, but there was produced no effect upon the curve. 



Experiment 12. — Rabbit, weight 3065 grammes, poison 1/5 gramme 

 (== 0"065 gramme per kilogramme). Both vagi divided before injection. 



Blood Pressure. — The pressure immediately began to rise, and from 

 144 to 146 mm. Hg it rose to a maximum of 190 to 192 mm. Hg during the 

 27 seconds after the injection. This maximum height was maintained for 

 15 seconds, when the pressure commenced falling, and death occurred 

 one and a half minutes after the poison was injected. 



Stimulation of Vagus. — The left vagus was stimulated (strength 10) when 

 the blood pressure had attained its maximum height. There was no direct 

 effect upon the blood-pressure curve, but it was altered indirectly through 

 the effect of the stimulation upon respiration. A second stimulation 

 produced no result upon the blood pressure, although respiration was 

 affected as before. 



Section of Spinal Cord. 



Experiment 13. — Cat, weight 2720 grammes. The spinal cord was 

 divided at the level of the third cervical nerve. Artificial respiration was 

 maintained at a rate of 39 per minute. Poison 1/20 gramme injected 

 intravenously (= 0'018 gramme per kilogramme). 



Blood Pressure. — The rise in pressure commenced 15 seconds after the 

 injection was given, and from a height of 38 to 40 mm. Hg it attained 

 a maximum height of 80 to 84 mm. Hg 200 seconds after the injection was 

 given. From this point the pressure curve gradually fell till the heart 

 stopped about seven minutes later. Before the pressure curve attained its 



