DR THOMAS R. FRASER ON STROPHANTHUS HISPIDTJS. 405 



brain and cord does not prevent Strophanthus from producing the same effects upon the 

 heart as follow the subcutaneous administration of large doses to uninjured animals. The 

 changes produced by such doses, therefore, are not the result of any action exerted upon 

 the brain and medulla. 



Influence of the Vagus. 



The characters of the modifications produced in the heart's contractions, and especially 

 the increase of its diastole, rendered it of importance to determine if these modifications 

 are in any way dependent upon an influence exerted by Strophanthus upon the physi- 

 ological condition of the vagus. With this object, paralysis of the vagus was produced 

 by atropine before Strophanthus was applied to the heart, and also after the heart's 

 action had already been affected by Strophanthus. A 0*2 per cent, solution of sulphate 

 of atropine was used, and, in preliminary experiments on frogs with the brain destroyed 

 and the heart exposed, it was found that the application of 2 minims of this solution 

 to the surface of the heart caused complete paralysis of the cardio-inhibitory function of 

 the vagus, lasting for at least 24 hours. 



The experiments were made in Autumn with well-nourished and perfectly healthy 

 frogs. The brain was destroyed ; and, after a moderate interval of time, the heart was 

 exposed, and the pericardium removed from its anterior surface, and the rate and 

 characters of the heart's contractions were recorded. 



Atropine before Strophanthin. — In the following five experiments the application of 

 strophanthin to the heart's surface was preceded by the application of atropine. 



Experiment CVIII. — Frog weighs 630 grains. - 0045 grain of sulphate of atropine 

 applied to the heart before 0"001 grain of strophanthin. 



10.46. Brain destroyed. 



10.50. Frog tied down, heart exposed, and pericardium removed. 



10.55. Heart's contractions 12 per 30 sec. Ventricular systole deliberate, and ventricle becomes moder- 

 ately small and pale on its completion. 



10.58. Do. do. 



11.0. Applied to surface of heart - 003 grain of sulphate of atropine in solution. 



11.3 to 11.10. Heart's contractions 13 per 30 sec. 



11.12. Applied to surface of heart 0-0015 grain of sulphate of atropine in solution. 



11.15 to 11.19. Heart's contractions 13 per 30 sec. 



11.20. Applied to surface of heart 2 minims of solution of 0'05 grain of strophanthin in 100 minims 

 0*6 per cent, saline ( = 0'001 grain). 



11.23. Heart's contractions 13 per 30 sec. 



11.25. Do. No interruption of ventricular systole; ventricular systole complete, and during it ventricle 

 seems smaller and paler than before. 



11.27 to 11.46. Do. do. 



11.49. Do. Systole longer, and diastole rather more abrupt than before. 



11.51. Heart's contractions 12 per 30 sec. A spot at apex of ventricle does not become pale during 



systole. 

 11.52 and 11.53. Do. do. 



11.55. Heart's contractions 11 per 30 sec. Ventricular systole good; diastolic dilatation greater than 



before, and with faint interruption ; occasionally, a small " pouch " during systole, at apex. 



