Physiologists have assumed that the symmetrical movement of the limbs as in swimming or rowing is the natural one; and the alternating or independent movements, as in walking or writing, are an acquisition involving inhibitions of the natural innervations. “Even in adult life,” says Professor James, “there is an instinctive tendency to revert to the bilateral movements of childhood.” Professor Münsterberg was led to doubt this view by observing the unsymmetrical motions of a baby in a warm bath, and experiment has confirmed his scepticism. Complicated joint motions of both hands (tracing circles or other geometrical figures on a surface) do not exhibit any tendency, when the attention is distracted, to assume the symmetrical form. They rather tend to compensate each other in such a way as to preserve equilibrium with the minimum strain on the other muscles of the body, and this law leads as often to alternating as to symmetrical movements of the arms or legs. The case is different of course with the muscles of the trunk, and may be different in birds, as it would in us if we spent our lives in swimming or rowing. A new method of attacking the problem of localisation is to observe the effect of altering the circulation in different parts of the brain. Tentative experiments on one subject seem to show that verbal associations are readiest when the victim lies on his left side, which is a happy coincidence with the localisation of the speech centres in the left frontal convolutions. If these statistics can be trusted, it is inadvisable to undertake hard mental labor with the head hanging back over the edge of a chair!