404 DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



That the changes in the heart's contractions are not the result of any action upon the 

 brain, has already been shown by the experiments in which they were produced after 

 destruction of the brain. 



In other experiments, such as the following, the whole medulla, as well as the brain, 

 was destroyed before the administration of Strophanthus. 



Experiment CVI. — Fifty-four min. after the brain and cord of a frog, weighing 

 250 grains, had been destroyed, the exposed heart was contracting regularly, though 

 feebly, at the rate of from 9 to 10 per 30 sec. 0*05 grain of extract of Strophanthus 

 was then injected under the skin of one thigh. In 30 min. thereafter, the heart's con- 

 tractions were 10 per 30 sec. ; and in 40 min., 8 per 30 sec. In 2 hours, the heart had 

 ceased to contract, and when standstill occurred the ventricle was pale and small, and 

 the auricles were large and dark. Mechanical irritation applied to the ventricle produced 

 no movement ; but when applied to the auricles, it produced a single faint contraction of 

 the auricles, which recurred on each of several repetitions of the irritation. 



That this paralysis of the heart in ventricular systole was not due to destruction of 

 the brain and cord is shown by the following experiment. 



Experiment CVII. — A. Twenty min. after the brain and cord had been destroyed 

 in a frog, weighing 290 grains, the exposed heart was contracting with regularity, at the 

 rate of 8 per 30 sec. O'l grain of extract of Strophanthus was then injected under the 

 skin of a thigh. The heart continued to contract, nearly regularly, for 1 hour thereafter. 

 In 1 hour 6 min., the auricles occasionally contracted twice for one contraction of the 

 ventricle. In 1 hour 15 min., the ventricle had become motionless in moderate systole, 

 while the auricles contracted 6 times in 30 sec. In 1 hour 20 min., the auricles had 

 also ceased to contract. For 1 5 min. subsequently, mechanical irritation of the ventricle 

 was followed, on each of several repetitions of the irritation, by a single contraction of the 

 ventricle and auricles ; but soon afterwards even strong irritation failed to excite any 

 movement of the heart. The ventricle was now small and pale, and the auricles were 

 dilated and dark. 



B. At the same time as Experiment CVII., A, was made, the brain and cord were 

 destroyed, and the heart was exposed in a frog, weighing 289 grains. The initial rate 

 of the heart — 8 per 30 sec. — was maintained for 4 hours. On the following day the 

 heart's rate was 6 for 30 sec. On the third day it was 7 per 30 sec, and the only other 

 change was feebleness of its contraction. On the fourth day it was 3 per 30 sec. On 

 the fifth day the heart was motionless, and non-contractile on irritation. (Experiment 

 CVII., A and B were made in winter, and the frogs were kept in a cold room with a 

 temperature that ranged between 36° and 40° F.) 



In Experiments CVI. and CVII. paralysis of the heart was very slowly produced, 

 considering that the doses of Strophanthus were large. In both experiments, however, 

 it was found that the circulation in the web of the foot had become extremely sluggish 

 before Strophanthus had been administered. With the exception of this slowness of 

 action, the result of delayed absorption, the experiments show that destruction of the 



