DR THOMAS E. TEASER ON STEOPHANTHUS HISPIDUS. 



403 



Experiments vrith Strophanthine 



No. of Experiment. 



Strength of Solution of 

 Strophanthin. 



Result. 



CIL, 



CHI., 



CIV., 



cv., . . 



1 : 15,000,000. 

 1 : 20,000,000. 

 1 : 20,000,000. 

 1 : 20,000,000. 



Paralysis of heart in 40 min. 

 Heart nearly paralysed in 1 hour 50 min. 

 Heart nearly paralysed in 1 hour 10 min. 

 Paralysis of heart in 1 hour 53 min. 



It is thus seen that so extremely dilute solutions as one part of extract in fifteen 

 million parts of fluid, and one part of strophanthin in twenty million parts of fluid, not- 

 only modify the contractions of the heart, but actually paralyse that organ. With solu- 

 tion of 1:4,500,000, 1:6,000,000, 1:8,000,000, 1:10,000,000, and even 1:20,000,000, the 

 reaction of the muscle of the ventricle, also, was found to be acid, within a few minutes 

 after paralysis had been produced. 



In an unpublished series of experiments, made with my former assistant, Dr Stock- 

 man, the effect on the heart of a number of other substances has been examined by this 

 method. It is interesting to state that none of them was found to be so powerful as 

 Strophanthus. Assuming one part of strophanthin in fifteen million parts of fluid to be 

 the limit of dilution able to paralyse the frog's heart, the experiment showed that 

 strophanthin is about eight times more powerful than adonidin, scillitoxin, or erytho- 

 phloeine ; twenty times more powerful than helleborein ; thirty times more powerful than 

 convallamarin ; three hundred times more powerful than digitalin ; * six thousand times 

 more powerful than saponin ; and more than thirty thousand times more powerful than 

 sparteine and caffeine. 



The action of strophanthin upon the heart is, therefore, more powerful than that 

 of any other substance, with regard to which data exist wherewith to institute a 

 comparison. 



III. Structures Involved and Nature of Involvement in the Production of the Changes 



in the Heart 's Action. 



In the generally recognised uncertainties regarding many points in the physiology 

 of the heart, the problem of the determination of the action or actions by which 

 Strophanthus produces its effects upon this organ becomes a difficult one to solve. In 

 endeavouring to arrive at a solution, several facts, in addition to those already stated, 

 have, however, been ascertained, which appear at least to narrow the problem. 



* This is when strophanthin is compared with Merck's purest digitalin. When experiments were made with the 

 English digitalin, used in the experiments on blood-vessels (p. 420), strophanthin was found to act upon the heart three 

 thousand times more powerfully than it. 



