Abstract
1) A suitable apparatus for perfusing the frog's heart, by which the metabolic action, mechanical work and electrical response of the heart can simultaneously be observed, was described. The relationship between the oxygen consumption, cardiac output and heart rate was studied to detect the most suitable conditions for making the tests.
2) The effect of drugs can be investigated by adding them into the circulating blood, and blood samples can be taken at will for chemical analysis.
3) Seasonal variations in the activity of the heart were demonstrated, and it was proved that these changes depended partly upon the lactate content in the blood.
