1906.] Recently -Discovered African Arrow Poison. 



37 



rate as the pressure commenced to fall. The beats had now become 

 extremely small. 



Respiration. — Xo change occurred in the respirations until the second 

 vagus had been cut, and then the respirations became of the vagus type. 

 The respirations became irregular and small as the heart stopped, and 

 inspiratory gasps were taken at intervals for 100 seconds later. 



Stimulation of Vagus. — Stimulation of the vagus 26 seconds after the 

 second vagus had been divided produced no effect whatever upon the heart 

 beats or blood pressure. No alteration was produced on again stimulating 

 the nerve with the full strength of current when the blood pressure had 

 attained its maximum point. A marked effect was, however, produced upon 

 respiration, which stopped suddenly. A third stimulation with the full 

 strength of current for a period of seven seconds was applied when the 

 blood pressure had commenced falling, but no effect whatever was produced 

 on the blood pressure or heart beats although the respiration stopped. 



Experiment 10. — Cat, weight 2930 grammes, poison 1/20 gramme 

 (= 0'017 gramme per kilogramme). 



Blood Pressure. — The blood pressure began to rise at once, and from 

 132 to 146 mm. Hg it reached 16-1 to 174 mm. Hg in 32 seconds. After 

 remaining stationary for 35 seconds it began to fall. When the pressure had 

 fallen to 150 to 168 mm. Hg the left vagus was cut, with the result that the 

 pressure immediately rose, and in 15 seconds reached 180 to 192 mm. Hg. 

 A second fall now occurred to 166 to 174 mm. Hg, and finally the pressure 

 rose again in a long curve to a maximum of 208 to 218 mm. Hg, and from 

 this point it gradually fell till death. Section of the right vagus before the 

 maximum point was reached produced no alteration in the pressure curve. 

 The blood-pressure curve fell very gradually and had many irregular rises 

 and falls on it towards the end. It reached 24 mm. Hg in 17£ minutes 

 after the poison was injected, and at this point death occurred. 



Heart Beats. — During the first rise the rate of heart beats was unaltered. 

 "Whilst the pressure was stationary and during the first fall the rate was 

 slowed from 231 to 216 per minute. After section of the left vagus the 

 rapidity slightly increased to 220 per minute, and during the second fall the 

 rapidity was 214 per minute. 



From, this point the rapidity gradually increased to 255 per minute when 

 the blood pressure was at its height. When the pressure was finally falling, 

 100 seconds later, the rapidity was still 255 per minute, and after this the 

 pulsations were too small to count. 



Respiration. — The respirations were very irregular during the whole 

 time, and typical vagus respiration occurred after section of both vagi. 



