THE PHARMACOLOGICAL ACTION OF HARM A LINE. 



267 



vagal mechanism was intact. The last dose (0'008 grm. per kilo) proved fatal in this 

 experiment probably because respiratory failure was caused by the added effects of 

 harmaline and atropine on the respiratory centre. However, a sufficient comparison can 



Table IX. — Experiment 34. 



Time. 



Injection. 



Average 

 B.P. 



Pulse 

 Rate. 



Result of Stimulation 

 of Left Vagus. 



1.15 





100 



40 





1.16 









130 mm. — arrest of heart. 

 140 „ slowing of heart. 

 150 „ nil. 



1.18 



A.S. 001 grm. per kilo 









1.20 









140 mm. — nil. 

 120 „ 



1.39 









140 ,, arrest of heart. 



1.40 



A.S. 0-002 grm per kilo 









1.40.30" 









140 mm. — nil. 

 100 „ 



1.42 





94 



36 





1.43 



H.H. 0-001 grm. per kilo 









1.43.30" 





102 



33 





1.44.20" 



... 







120 mm. — nil. 



1.46 





102 



31 





2.15 









120 mm. — slowing of heart. 



2.25 









120 „ 



2.26 



A.S. 0-002 grm. per kilo 









2.29 









120 mm. — nil. 



2.29.30" 





79 



28 





2.30.10" 



H.H. 0002 grm. per kilo 









2.31 



... 



82 



24 





2.33 



. . . 



90 



23 



1 



2.36 





92 



22 





2.37 









120 mm. — nil. 



2.38 



H.H. 004 grm. per kilo 









2.38.30" 





84 



19 





2.39 





88 



20 





2.42 





96 



19 





2.45 









120 mm. — slowing of heart. 



2.52 



A.S. 0001 grm. per kilo 









2.55 





88 



22 





2.55.40" 



... 







120 mm. — nil. 



2.56 



H.H. 0-008 grm. per kilo 









2.56.40" 





52 



18 





2.58 





30 



13 





3.0 





22 



12 





3.3 















be made to allow the conclusion that, except in the case of the first injection, the slowing 

 of the heart is not due to central or peripheral stimulation of the vagus, but to an 

 action on the cardiac muscle. This result corresponds with that obtained in perfusion 

 experiments on the frog's heart where the slowing of the heart produced by harmaline 

 was not prevented by simultaneous perfusion with atropine. 



