a dim sub-consciousness. But there are many molecular changes (even in the cerebral hemispheres themselves where consciousness is “called into existence”) which do not rise to the level of consciousness at all or are quite lost in the glare of that consciousness. Why this should be so I am not prepared to say. It seems to be a law of our mental being. Certainly it is convenient that it is so; and it may have been fostered or established by natural selection. We all know the sense of confusion that arises when, in certain states of intense nervous excitement, a host of ideas are crowding up into dominance and jostling each other for supremacy. An organism so constituted that such a state of things was normal, would, we may suppose, stand but a poor chance of survival. Hence perhaps there has arisen that due subordination of conscious, sub-conscious, and infra-conscious states which characterises the normal life of conscious beings. Having regard, then, to the cerebral hemispheres where consciousness emerges, not all the molecular changes there transpiring rise to the level of full consciousness. There is not a little of what Dr. Carpenter used to call unconscious cerebration. We seem forced to admit the existence of submerged states of consciousness; states which are infra-conscious, but which may become conscious at any moment by rising into dominance. And if in the cerebral hemispheres there are infra-conscious states, why should there not be associated with every molecular thrill of the living body yet lower states of infra-consciousness too deeply submerged ever in man to become dominant?