42 



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



When the pressure curve was at its maximum height the rate was 

 204 per minute. The beats became much smaller and 228 in frequency as 

 the pressure was falling. The last time the beats could be distinguished the 

 rate was 280 per minute. 



Experiment 14. — Cat, weight 2750 grammes. Spinal cord cut opposite 

 third cervical nerve. Poison 1/20 gramme given twice (= 0'018 gramme 

 per kilogramme). 



The same sequence of events was observed as in Experiment 13. After 

 a second injection of the same amount of poison during the period of large 

 heart beats the pressure rose somewhat suddenly, the heart beats becoming- 

 smaller and showing a respiratory rhythm. Towards death the heart beats 

 became irregular and rapid. 



Section of Splanchnic Nerves. 



Experiment 15. — Cat, weight 2470 grammes. Artificial respiration. The 

 chest was opened on both sides, and both splanchnic nerves divided 

 above the diaphragm. Poison 1/10 gramme injected (= - 04 gramme per 

 kilogramme). 



Blood Pressure. — The blood pressure commenced rising 12 seconds after 

 the injection was given. During the rise a period of slowing of the heart 

 beats occurred as in the spinal cord experiments. This only lasted about 

 25 seconds, and slightly interrupted the rise of blood pressure. The 

 maximum height of the blood pressure was 126 to 138 mm. Hg, and this 

 occurred two minutes after injection, the blood pressure before injection 

 being 56 to 64 mm. Hg. During the next 70 seconds the pressure gradually 

 fell to 90 to 100 mm. Hg. The right splanchnic nerve was now stimulated 

 (strength of current, 12), and the pressure in response to this immediately 

 commenced rising and reached the height of 136 to 144 mm. Hg. In the 

 next 25 seconds it gradually fell to 50 mm. Hg. The splanchnic nerve was 

 again stimulated with the same strength of current, and the blood pressure 

 rose to 80 mm. Hg. The heart now rapidly failed, and in 20 seconds had 

 stopped, the pressure falling to 20 mm. Hg above zero. 



Before injection the rate of the heart was 198 per minute. As the 

 pressure was rising the rate fell to 117 per minute. When the maximum 

 pressure was reached the frequency was 249 per minute. As the pressure 

 fell the heart began beating irregularly and the rate was 255 per minute. 



Previous Injection of Apocodein. 



Experiment 16. — Eabbit, weight 2720 grammes. Apocodein 1/10 gramme 

 injected (= - 036 gramme per kilogramme). The blood pressure immedi- 



