1906.] Recently-Discovered African Arrow Poison. 



49 



the heart commenced beating again, the beats gradually increasing until they 

 reached their former size. The rate was 27 per minute. 



On the application of more of the poisoned solution, the heart again 

 stopped. A second stimulation after a longer latent period than before 

 caused the heart to recommence beating. This time the beats did not attain 

 their former size. Eate, 21 per minute, the beats being somewhat irregular. 

 The heart soon stopped on its own accord, and a third stimulation restarted 

 the contractions, which gradually died away, and now a further stimulation 

 failed to restore the contractions. 



Experiment 4. Pithed Frog. — Poison, 1/10 gramme to 1 c.c. Einger's 

 solution. The heart was stopped except for a tiny and feeble contraction of 

 the auricle by application of the poison. A stimulus applied to the sinus as 

 in Experiment 3 restored the heart beats. When the beats had attained 

 their normal size, the application of more poison stopped the heart and 

 stimulation now failed to arouse it. 



Experiment 5. Pithed Frog. — Poison, 8 per cent, in Einger's solution. 

 The first effect of the poison was a gradual diminution in the size of the 

 ventricular beats until they became the same size as the auricular beats and 

 finally smaller. At this stage slow peristaltic action of the ventricle 

 occurred, passing from base to apex. The ventricle also dropped beats and 

 thus a marked irregularity of action was produced owing to a block at the 

 auriculo-ventricular junction. On discontinuing the application of the 

 poison the ventricle recovered itself. 



More poison was applied and again the ventricle showed the same action 

 as before and finally recovered a second time on the application being dis- 

 continued. A third application of the poison brought the ventricle to a 

 standstill, the auricle continuing to beat. A 5-per-cent. solution of atropine 

 was now applied. 



There was no result for a little while and then the rate of the auricular 

 contractions became much slower, and finally the rate sank from 39 to 12 

 per minute. The heart was not restored. 



Experiment 6. Pithed Frog. — Atropine, 5 per cent, in Einger's solution 

 applied. The heart was now beating at 33 per minute. After 70 seconds an 

 8-per-cent. solution of the poison (Einger's solution) was applied. The heart 

 continued to beat at the same rate for about 40 seconds, and then the rate 

 increased to 42 per minute, the beats becoming smaller ; when the ventricular 

 beats had become the same size as those of the auricle the rate was 33 per 

 minute. The ventricle stopped in diastole, the auricle continuing to beat for 

 a short time, when the heart finally stopped. 



Experiments 7, 8, 9, 10, 11. — Five more experiments with the frog's heart 



VOL. LXXVIII. — B. E 



