1906.] 



Recently -Discovered African Arrow Poison. 



35 



Blood Pressure. — The pressure curve began to rise 13 seconds after the 

 commencement of the injection, and in 26 seconds it had risen from 

 160 mm. Hg to 182 mm. Hg. There then occurred a slight fall in the 

 pressure to 178 mm. Hg. After 220 seconds the pressure had risen to 

 200 mm. Hg, its maximum point, and then succeeded a rapid fall to 

 20 mm. Hg as the animal died. 



Pulse Rate. — Before the injection the rate of the heart was 228 per 

 minute after the preliminary rise of pressure, and when it was falling the 

 rate fell to 204 per minute. It again increased, and 120 seconds after the 

 injection, which was the last point at which it could be counted, it had 

 reached 240 per minute. 



Respiration. — The respiration was unaffected and became spasmodic as 

 the heart stopped. After the blood pressure had fallen to its lowest point 

 a series of very deep inspiratory gasps occurred, which gradually died away 

 in four minutes. 



Stimulation of the Puight Vagus. — Before the poison was administered 

 stimulation of the vagus (strength 12) produced a fall in the blood pressure 

 of over 30 mm. Hg. The vagus was stimulated 93 seconds after the injection 

 was given (strength 12) for 15 seconds. After the stimulation had ceased 

 a hardly appreciable fall in the blood pressure occurred. The vagus was 

 stimulated 40 seconds later (strength 10) for 17 seconds, and during the 

 stimulation the pressure rose somewhat higher. When the pressure had 

 commenced to fall rapidly, a third stimulation for live seconds (strength 10) 

 produced no effect on the pressure curve. 



Experiment 7. — Cat, weight 2500 grammes. Poison 1/15 gramme 

 (= 0"026 gramme per kilogramme). 



Blood Pressure. — Ninety seconds after the injection the blood pressure 

 had risen from 184 mm. Hg to 216 mm. Hg. The right vagus was now cut 

 and the pressure at once went up, reaching a height of 226 mm. Hg in one 

 second. The pressure gradually went up to 232 mm. Hg during the 

 102 seconds following, and now the left vagus was cut, but no alteration 

 occurred in the pressure curve except that the respiratory undulations 

 became well marked. The pressure fell to its lowest point 180 seconds 

 later. 



Heart Beats. — When the right vagus was cut the heart was accelerated in 

 rate by 24 beats per minute. No notable acceleration occurred after the 

 left vagus was cut, but the heart beats gradually increased in frequency and 

 just before the blood pressure finally fell they were 246 per minute. 



Respirations. — The respirations were markedly affected on division of the 

 vagi, becoming quite characteristic in type. 



D 2 



