THE PHARMACOLOGICAL ACTION OF HARMALINE. 



259 



combined solution brought about arrest of the ventricle in the same way as was pro- 

 duced previously by the same strength of harmaline without atropine. 



These effects are detailed in the following table :- 



Table VI. — Experiment 28. 





Rate 



Amplitude 







Time. 



per 

 Minute. 



of 

 Excursus. 



Notes. 





12.33 



22 



25 







12.36.30" 







Solution of H.H. 1 in 10,000 turned on (fig. 4). 





12.40 



16 



24 







12.48 



13 



19 







12.53 



8 



19 



Fig. 6. 





12.59 















1.1 







Normal solution turned on (fig. 7). 





1.2 



11 



15 







1.3 



19 



14 







1.7 



23 



25 







1.14 



27 



25 







1.15 







Solution of H.H. 1 in 10,000 turned on. 





1.17 



7 



25 







1.20 



2 



23 







1.22 



1 



20 







1.23 















1.25 





• • • 



Normal solution turned on. 





1.26 



11 



18 







1.31 



26 



25 







3.48 



27 



24 







3.51 







Solution containing H.H. 1 in 10,000 and A.S. 1 

 turned on. 



in 100,000 



3.53 



2 



20 







3.54 















Experiment 29. — Strength of solution, 1 in 20,000. 



This solution, in three and a half hours, reduced the rate of beat from 25 to 9 per 

 minute, and the amplitude of excursus from 28 mm. to 21 mm. Complete recovery was 

 then brought about in fifteen minutes by re-introduction of the normal solution. The 

 harmaline solution, to which had been added atropine sulphate in the proportion of 

 1 in 50,000, was then perfused, but the addition of atropine did not prevent the slowing 

 of the ventricle produced by harmaline. 



Experiment 30. — Strength of solution, 1 in 50,000. 



Perfusion of the ventricle with this solution had practically no effect on the heart 

 in two and a half hours. 



These experiments show that very strong solutions of harmaline bring about 

 abrupt systolic arrest of the heart, an effect probably similar in nature to the rigor of 

 voluntary muscle which strong solutions of harmaline have been shown also to effect. 



The characteristic action of harmaline on the heart, however, is to slow the rate 



