1906.] 



Recently -Discovered African Arrow Poison. 



33 



Heart Beats. — At the end of the first rise of pressure the heart became a 

 little slower and the beats slightly larger. At the end of the first fall the 

 rate of the pulsations had dropped from 195 per minute to 126 per minute, 

 and were decidedly larger. After this point till death the pulsations became 

 gradually smaller and the rate more frequent, the latter being 246 when they 

 could be last counted, about 100 seconds before the pressure reached its lowest 

 point. 



Respiration. — Before the injection was given the respirations were a little 

 irregular, and they were quite unaltered by the injection. They became a 

 trifle shallow during the last minute of life. As the heart stopped about 

 10 small irregular respirations occurred, and a minute later three small 

 inspiratory gasps at intervals of 10 seconds were taken. 



Compression of Abdomen. 



Experiment 3. — Cat, weight 3220 grammes. Poison 1/10 gramme 

 (= 0"031 gramme per kilogramme). A smaller dose of the poison was given 

 so as to produce a slow heart failure. The animal lived for about half an 

 hour. The kymograph drum was allowed to go round twice, and it had 

 commenced its third revolution when the blood pressure, which had been 

 gradually falling, reached 60 mm. Hg. The abdomen was compressed, and 

 the blood pressure immediately went up to 95 mm. Hg; the compression was 

 kept up for 37 seconds, and as soon as it was relaxed the blood pressure 

 immediately fell to 60 mm. Hg again. 



The abdomen was again compressed for 35 seconds. The blood pressure 

 rose to a maximum of 120 mm. Hg, and when the compression had been 

 maintained for 18 seconds the blood pressure suddenly fell straight down 

 to 34 mm. Hg and the heart stopped. When the compression was relaxed 

 there was a further fall to 20 mm. Hg above zero. The heart had failed 

 before the extra work that was presented to it by increasing the flow of 

 blood into its right cavities during diastole. 



Section and Excitation of the Vagi. 



Experiment 4. — Cat, weight 2750 grammes. Both vagi divided before 

 injection. Poison 1/10 gramme (= 0*036 gramme per kilogramme), the 

 dose being repeated. 



Blood Bressure. — Immediately the injection had been given the blood 

 pressure began to rise, and during the first six minutes after the injection 

 it rose from 162 to 180 mm. Hg to a maximum of 194 to 210 mm. Hg. 

 After this it gradually fell to 184 to 162 mm. Hg, and now a second 

 VOL. lxxviii. — B. D 



