is controlled by will and that other part by physical and chemical forces. We might with equal propriety divide the social unity into two classes, and one we may describe as men, the other as marionettes. If, however, we adopt this classification, and divide all organic movements into either voluntary and conscious, or involuntary and unconscious, we have to ask, What is that power which produces involuntary movements? Το will to move one's arm is a voluntary and conscious act, but one cannot will the peristaltic movements of the intestinal canal. The latter movements Sir James Paget ascribes to what he calls "rhythmical nutrition," which is just as good an explanation of the phenomena as any I have met with. To assert that they are due to reflex action does not help us in the least, for we still want to know what causes reflex action; and the further assertion that "the ganglionic cells have an independent power of action" has no meaning, unless we are to understand by this statement that such cells have the power of action possessed 1 Croonian Lecture before the Royal Society, 1857. by Cephalic cells, which is what we contend for. It may be objected, however, that if there were two or more centres of psychical activity in the same body, there would be two or more separate and independent powers, which is absurd. There may be two or more separate, but certainly not independent, powers. There are subordinate nerve centres, and there is a supreme nerve centre, just as there are local centres and a supreme centre in the social organism.1 In like manner, we may assume there are local psychical centres, as we know there is a supreme psychical centre. Almost all physiologists now admit that there is in all organisms, except the lowest, at least one other great centre besides the cerebrum, namely, the spinal cord. Maudsley held that the spinal cord exercises volition; Vulpian, that its action is systematic, adaptive and intelligent in every instance; while Greisinger, Prochaska, Nasse, Carus, Schiff, Legallois, Landry, Laycock, Carpenter and Lewes maintained that the actions of the spinal cord are of the same order as those of the cerebrum. If it were necessary one might take, seriatim, the other sub-centres between the cerebrum and the spinal cord, and show how each of these has its own psychical functions, and thence proceed to exhibit the psychical functions of the ganglia elsewhere. But, once admit that there are more centres than one, and the objection falls to the ground; and if more than one, where are we to stop? How are we to draw a line between a ganglion in the cerebrum, another in the spinal cord, and a third at the periphery? E CHAPTER III CONSCIOUS AND UNCONSCIOUS STATES The term Conscious-Evolution of the nervous system-On the co-extension of mind and consciousness-Objections to this view-What is herein involved-Evidence in favour of unconscious mental states-The phenomena of alternate consciousness—Limitations of the Ego-Correspondence between the sub-centres and the hemispheresThe Unconscious. STRICTLY speaking the term consciousness can be applied only to our own individual feelings and experiences, not to the feelings and experiences of others. I may say I am conscious that I entertain no ill feeling towards a certain person, but not that I am conscious that a certain person has no ill feeling towards me. Consciousness is a wholly personal matter. The term is used to indicate the state of the knowing subject, the conscious self, the Ego. Hence it is inaccurate and often misleading to use it to denote psychical activity generally, or as a synonym for mind, as is often done. But we have to retrace our steps. All organisms consist either of a single cell, or of an aggregation of cells, and all multicellular organisms begin life as a single cell, which divides and redivides, and so multiplies into a coherent mass of cells forming a compound organism. All the cells in this compound organism having orignated in a single germ cell, and been propagated by division, would, in the first instance, be exactly alike in composition, structure and disposition, and would therefore have a common ideal, and would work for a common end. But as the structure developed a division of labour would take place, different cells would exercise different functions, and eliminate different materials from their environment for the building up of the organism. Thus, modifications in the composition and in the character of the cells would, in course of time, arise, and so a cell which produces muscle tissue would differ from a cell producing fat or bone or nerve tissue. Cells would also assume different shapes according to the position which they occupied in the tissue, owing to the presence or absence of strain or pressure on |