Summary.By means of injections of prostigmine a comparative study of the effect of ether and curare in the motor endplate has been carried out. The results of the investigation are:1Prostigmine affects the neuro‐muscular transmission which is inhibited by ether and curare in different ways. This demonstrates that the substances must exert their effect in the motor endplate by essentially different mechanisms.2The effect of ether can be only partly explained by a decreased sensitivity for ACh of the muscle cells.3On the basis of previous in vitro‐experiments, ether has been suggested to have a prostigmine‐like effect. The present experiments, however, show that this assumption is unte