392 DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



then occurred, when four strong and rhythmical cardiac contractions took place during 

 20 sec, but the auricles appeared to contract less powerfully than the ventricle; 

 the heart then became motionless in extreme diastole of both ventricle and auricles, 

 for 2 min. and 40 sec, when, after a few struggles, one rhythmical and strong 

 cardiac contraction occurred, and was again followed by standstill of the heart in 

 extreme diastole, lasting for 40 sec, at the end of which time two contractions took 

 place after a few struggles, and were followed by standstill of the heart in extreme 

 diastole. During the state of motionlessness all the chambers of the heart were always 

 large and dark, contrasting markedly with the state of systolic contraction with paleness 

 of the ventricle observed in Experiments LXVII.-LXXXIIL ; when several contractions 

 occurred to interrupt the prolonged pauses of the heart, the intervals were longer between 

 the later than the earlier of the contractions ; and the diastolic dilatation of the ventricle 

 during the more prolonged pauses was greater at the beginning than at the end of the 

 pause. At 24 and at 26 hours after the administration, the heart's action was characterised 

 by the same features as those above noted, and, even at the latter time, throat respirations 

 frequently occurred ; but while the heart was motionless, struggles or respiratory move- 

 ments were not now followed by contractions of the heart so invariably as before, and 

 the periods of standstill in extreme diastole often exceeded 3 min. 



In view of the obvious bearing upon the use of Strophanthus in the treatment of 

 heart disease, it would have been valuable to have obtained evidence of the nature of 

 the changes produced by small doses on the heart's contractions, from the time of adminis- 

 tration until the production of the final effects, in animals with the entire cardiac 

 innervation uninjured ; but the requisite permission to perform these experiments could 

 not be obtained from Her Majesty's Secretary of State. The experiment quoted, however, 

 appears to show that, after absorption into the blood, small, as contrasted with large, 

 doses of Strophanthus increase the diastole of the ventricle, and slow the heart by 

 prolonging diastole rather than systole. Further evidence of the production of these 

 effects by small doses will be adduced in the description of the experiments in which 

 Strophanthus was directly applied to the surface of the heart in pithed frogs. 



b. After Direct Application to the Surface of the Heart. 



Effects of a similar kind to those observed when the administration is so effected that 

 Strophanthus is conveyed to the heart by the blood-stream, and similarly varying with 

 the dose, are produced when it is directly applied to the heart. In the experiments 

 subjoined, illustrative of these effects, the frogs had been recently caught, and they were 

 in perfect health and nutrition. The experiments were made in the month of August. 

 In each experiment, after the brain had been destroyed, the heart was exposed, and the 

 pericardium was generally removed from its anterior surface. 



Experiment LXXV. — In this experiment the frog weighed 662 grains, and 0*001 

 grain of strophanthin was applied to the heart ( = , 000151 grain per 100 grains). 



