III. A NOTE ON THE ACTION OF PILOCARPINE, ATROPINE AND ADRENALINE UPON THE TONUS WAVES IN THE TERRAPIN HEART

¹ From the Department of Physiology and Pharmacology and the Henry S. Denison Research Laboratories in the University of Colorado

In my experiments pilocarpine hydrochloride in small doses 0.0005 to 0.05 per cent produced an increase in the tonus and tonus waves in less than 6 per cent of the experiments performed. These results are contrary to Fano and Bodano's findings. The difference is probably due to a difference in the strength of the solutions employed. The latter observers used 20 per cent solutions.

Atropine sulphate has no action on the tonus waves. These results confirm those of Bottazzi.

Adrenaline chloride decreased the increased tone set up by pilocarpine and simultaneously increased the height and rate of the contraction. In six other experiments performed, in which pilocarpine produced only a slowing of the heart rate and decreased the height of contraction, adrenaline antagonized the pilocarpine action.