The movement of stomach of the young rabbits reared under the same conditions as the previous tests for 35 days was observed by the balloon mehtod. Adrenalin and acetylcholin were then injected into the veins of the ear and their effects on the movement of stomach were studied. The following results were obtained by these kymographic records 1. The movement of stomach of the young rabbits under hot and humid environment showed a remarkable decline in comparison with that of control animals. 2. Both the inhibiting action of adrenalin and the exciting action of acetylcholin on the movement of stomach were reduced under these conditions.