454 DR THOMAS R. FEASER ON STROPHANTHUS HISPIDUS. 



injection. At this time, the blood-heart was exposed, and its ventricle was found to be 

 motionless in strong systole, although the auricles yet continued to contract at the rate 

 of 3 per 30 sec. During the following 20 min., the lymph-hearts spontaneously and 

 nearly regularly pulsated at the rate of from 16 to 21 per 30 sec. ; but 6 min. afterwards, 

 the pulsations had become infrequent and irregular. The observations were now 

 interrupted, and when resumed, at 1 hour and 25 min. after the administration of 

 Strophanthus, the pulsations of the lymph-hearts had altogether ceased. At this time, 

 and for 20 min. longer, active general reflexes could easily be excited. 



The lymph-hearts, therefore, retained their power of spontaneously pulsating for at 

 least 26 min. after paralysis of the ventricle of the blood-heart had been produced. 



F. Action on Eespiration. 



The relation between respiration and circulation is so intimate, especially in warm- 

 blooded animals, that much disturbance of the circulation, such as is produced by large 

 doses of Strophanthus, must affect respiration. 



In several of the previously described experiments on rabbits, the changes that occur 

 in the respiratory movements, as well as in the heart's action, have been noted (see 

 Experiments VII., VIII., XVI., XVIIL, XXXIL, XXXIIL, XXXV., and XXXVL). 

 In a few experiments, an increase occurred in the rate of the respirations soon after the 

 administration of Strophanthus, but it was only slight and of brief duration ; and it was 

 soon succeeded by a diminution in the rate, nearly coinciding with a reduction in the 

 number of the heart's contractions. In all the experiments in which lethal doses had 

 been administered, this diminution, like the similar change in the heart's rate, became, 

 abruptly marked towards the end of the experiment. 



While, however, in only a few of the experiments did decided slowing of the heart's 

 contractions occur earlier than of the respirations, in the majority of the experiments 

 distinct slowing in respiration occurred earlier than in the heart's contractions. 



With considerable or large lethal doses, the slowing of respiration appeared almost 

 entirely to result from the rapid and energetic effects of such doses upon the heart ; 

 but with minimum-lethal or non-lethal doses a slight direct paralysing action on 

 respiration appeared to be indicated in addition to the indirect effect produced by 

 changes in the circulation. 



The explanation of this direct action upon respiration may probably be found in 

 the feeble action of Strophanthus on the spinal reflex functions, and above all in the 

 powerful action on muscular contractility already discussed. Even before marked slowing 

 of respiration had been produced, the latter was manifested by the fibrillary twitches 

 that occurred, and by the general muscular feebleness which rendered the muscles of the 

 neck and limbs unfit steadily to support the head and body of the animal. 



That the marked embarrassment and failure of respiration which so conspicuously 

 follow the administration of large doses, depend more upon failure of the heart's action 



