Testing motor functions of the frontal zone in the locomotion of Amoeba proteus.

The hypothesis which attributes the motive power to the frontal zone has been tested by cinematographic analysis of the movements of amoeba, in which the front was either blocked by negative stimuli or destroyed. Partial inhibition and consecutive reorganization of the frontal activity by a beam of light had minor effect on the retraction of other body parts. Microsurgical destruction of the whole frontal zone had no effect on the functions of more posteriorly situated cell regions, which continue to contract and squeeze the endoplasm out into the external medium.