Changes in the heart rate after procaine.

In studying "the inhibitory action of procaine upon the reflex-bradycardia*," it was found to be necessary to make more detailed observation on the changes in the heart rate after procaine itself. Krause(1) reported recently that novocaine injected intravenously on dogs usually produced an increase of heart rate with a rise of blood pressure which continued from 2 to 15 minutes. The author's results on cats however did not fully agree with him. The heart rate was sometimes increased and at other times decreased. The mode of the change seemed to vary largely according to either the dose of procaine or the individual of the cat, and the present study was undertaken previously.