STROPHANTHUS SARMENTOSUS : ITS PHAEMACOLOGICAL ACTION. 407 



on frogs which indicated that S. sarmentosus had but little effect on the blood-vessels, 

 that its action on the heart is a powerful one, and that the cardio-inhibitory function of 

 the vagus nerve plays no important part in that action. 



(d) Action on the Lymph-Hearts of the Frog. 



Experiment LXXIII, — At 12.10 p.m., a large frog {Rana esculenta) received by 

 subcutaneous injection into the left flank a dose of extract of S. sarmentosus equal to 

 - 05 gram per kilogram — more than ten times the minimum-lethal dose. Previous to 

 injection, the brain had been destroyed. Before the injection the lymph-hearts were 

 beating at the rate of 11 per 10 seconds. In 18 minutes after the injection, their rate 

 was 12 per 10 seconds. In 28 minutes, the lymph-hearts were contracting vigorously 

 at the rate of 1 1 per 1 seconds, and they continued to do so during the next ten minutes. 

 In 45 minutes, the rate was 18 per 10 seconds, and the movements were feeble. In 

 55 minutes, the rate of the lymph-hearts was 10 per 10 seconds, and their movements 

 were feeble and irregular ; and at this time, the exposed blood-heart was found to be 

 quite motionless. In 1 hour, the lymph-hearts were contracting at the rate of 9 per 

 10 seconds, and they continued beating at this rate during the next ten minutes, though 

 their contractions were irregular in time. In 1 hour 22 minutes, the rate of the lymph- 

 hearts was 4 per 10 seconds. In 2 hours 5 minutes, the lymph-hearts were contracting 

 at the rate of 9 per 10 seconds, but their movements were feeble and irregular in time. 

 In 2 hours 40 minutes after the injection, the contractions of the lymph-hearts had 

 entirely ceased. 



The lymph-hearts, therefore, were not paralysed by S. sarmentosus until more than 

 70 minutes after the contractions of the blood-heart had been arrested by it. 



F. Effects on Respiration. 



In the investigation of the general effects on frogs the respirations were observed to 

 become slower and more deep soon after the injection, but later the respiratory move- 

 ments were feeble and irregular. In those cases where rapidly fatal doses were ad- 

 ministered, the changes in the respiration were such as can be attributed to the effects 

 on the heart. In some cases (Experiment XL), the flanks became inflated by a series 

 of inspirations, as though there was some obstruction in the glottis, and were then 

 deflated by a single expiration. 



In warm-blooded animals the effects of large lethal closes on the respiration were 

 secondary to the action upon the heart. With non-lethal and small lethal doses, the re- 

 spirations were slowed and their amplitude was increased, changes which were observed 

 in the blood-pressure experiments as well as in the experiments to ascertain the general 

 effects of S. sarmentosus. In rabbits, periods of inspiratory dyspnoea frequently occurred, 

 accompanied with sounds apparently produced in the glottis. 



