:NS DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



D. Action on the Heart and Blood-Vessels. 



A. Heart. 



In the description of many of the experiments illustrative of the general action of 

 Strophanthus, as well as of such of its special actions as have already been considered, 

 the existence of a conspicuous and powerful action upon the heart has been rendered 

 apparent. 



In order to determine the nature of the changes produced upon this organ and the 

 energy of the action, and to define the structures whose function is modified, as well as 

 the character of the modification, a number of further experiments were made. Having 

 previously shown that the pharmacological action of the two extracts used in this 

 investigation and that of strophanthin are altogether the same in quality, it is unnecessary 

 to distinguish, by any arrangement of the narrative, the experiments made with each of 

 these substances. 



1. Nature of the Changes, — a. After Absorption into the Blood. 



Experiment LXVII* — One-tenth of a grain of extract was injected under the skin 

 of a small frog, whose heart had previously been exposed. Five min. thereafter, the 

 ventricular systole was somewhat prolonged; in 6 min., the ventricular diastole was 

 imperfect, so that only portions of the ventricle dilated to admit blood from the auricles; 

 in 6 min. 30 sec, the greater portion of the ventricle was continuously pale and 

 contracted, each auricular systole propelling merely a small drop of blood into the 

 ventricle, where it produced a dark pouch -like projection, which at times disappeared, 

 and at other times only changed its position during the imperfect systole of the 

 ventricle ; in 7 min., the ventricle altogether ceased to contract, while the contractions 

 of the auricles continued at nearly the original rate; and in 18 min., the auricles, in 

 their turn, became motionless, but, in place of being small and empty like the ventricle, 

 they were large and full of blood. Notwithstanding this absolute paralysis of the heart, 

 respiratory movements occurred for 25 min. after the ventricle had ceased to contract, 

 and the frog jumped about for some time afterwards. 



Experiment LXVIII. — In a frog, weighing 305 grains, the exposed heart was found 

 to be contracting regularly, at the rate of 15 per 30 sec. 0*05 grain of extract was 

 injected under the skin at the lower part of the right flank. In 5 min., the heart's 

 contractions were 15 per 30 sec, and regular. In 6 min., however, they had become 

 irregular ; the ventricular systole was prolonged, and pouching of the ventricle occasion- 

 ally occurred. In 7 min., the rate was 8 per 30 sec ; and in half a minute afterwards, 

 only minute portions of the ventricle darkened in diastole. In 8 min., the whole of 

 the ventricle was in a state of continuous systole, while the auricles contracted with 



* Published in Proc. Roy. Soc. Edin., vol. vii., 1869-70, p. 101. 



