Abstract
(1) In the present investigations the rabbit's intestine was immersed in blood-Tyrode, Tyrode or Ringer at 38°. Only in the aerated Ringer was the reversal effect of adrenaline observed, though infrequently, but when the adrenaline solution was aerated with oxygen gas for 20 or 30 minutes and added to the Ringer, the reversal effect was invariably observable. Therefore the decomposition product of adrenaline by oxygen must be taken as responsible for occurrence of this reversal effect of adrenaline.
(2) Toad's leg vessels were perfused with the normal Ringer, the summer-Ringer, the winter-Ringer and Göthlin's solution, and the experiments were carried out in all seasons. Various dilutions of adrenaline, that is, from 1:1 million to 1:100 milliards, were injected. In almost all cases no reversal effect was witnessed.
(3) The tone of the toad's leg vessels often fluctuate rhythmically. The often large waves vary within somewhat wide limits: The duration varies from 8 to 24 minutes, the drop number variation is of the extent of 2-16 a minute (percentage difference 3.6-17.8).
