in the brain? Not only would these nerve cells be of no use where they are, but they would prove a positive obstruction to the passage of the molecular motion. The end organs of sense are also provided with special groups of nerve cells lying between these organs and the brain, which we may assume to exist for the purpose of interpreting and transmitting as sensation to the brain the external stimuli which they receive through these organs. And surely a stimulus which did reach the brain and did not indicate whence it came would be as valueless to consciousness as a telegraph message would be to the recipient without the address of the sender.

The spinal cord is a column of nerve cells, bound together for the reception, modification and distribution of sensory impulses, and it performs its functions independently of the brain. The Medulla is another important centre, which controls the functions of the heart, the bloodvessels and the respiration and certain reflex actions. The basal ganglia of the brain and of the cerebellum are sub-centres for the coordination of muscular movements with the impulses of sense, all of which perform their

functions unconsciously. What conceivable purpose can these organs serve unless they share with the cerebral hemispheres the control of organic functions? Why should it be assumed that the ganglia at the periphery and in the sub-centres perform functions not only different in degree but of a different order from the ganglia in the brain? The assumption could only be justified by evidence showing that the ganglia in the brain are different in kind from those in other parts of the organism, or that the mere aggregation or massing of them in the brain will enable them to act differently from those elsewhere; but no evidence whatever has been produced in favour of either alternative. On the other hand, the behaviour of brainless and headless frogs and other animals proves conclusively that the brain is not the sole organ of sensation and of consciousness.

Moreover, the theory under consideration altogether ignores the principle of division of labour which almost everywhere prevails in organic life. Only in the very lowest forms of life (the unicellular) do we find the whole organism employed in performing every organic

function; in all animals higher in the scale special organs are provided for the performance of special functions. But if the brain were the sole seat of sensation it would also be the sole means of communication between the organism and the outside world, and all organic functions, voluntary and involuntary alike, would be directly controlled by the brain, and there would consequently be no necessity for any system of division such as now exists.

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The recognition of the principle of the division of labour in mental science will throw a flood of light on a large class of phenomena, and help us towards the solution of many problems. For example, it will explain

difficult

(1.) The true character of reflex action. As the term implies, reflex action is a twofold process; it is action and reaction, both of which are generally supposed to be physical in their nature. Literally, reflex action is action thrown, and action thrown back-a bound and a rebound; but the bound is not of the same nature as the rebound. The former is no doubt mechanical; but the latter, or reaction proper, is action of another kind; it is a response to the mechanical movement, an answer to a call

or an intimation of some sort. But there can be no response to a movement, molecular or mechanical, which has not been felt. Sensation must therefore precede the response, otherwise the latter would be a mere repetition of the molecular movement, which would be meaningless and futile. The most simple reflex action must necessarily have a psychical content, whether it proceeds from the brain or from a sub-centre, or a a peripheral ganglion. The sub-centres and ganglia react on a stimulus precisely in the same manner as the brain reacts on a stimulus. In both a sensation precedes a response; in both the sensation is accompanied by consciousness; but the sensation in the one case is local, and in the other it is general, the stimulus in the latter case having reached the chief centre (the brain) of sensation and of consciousness. Such stimuli as do not reach the chief centre are not lost; they are intercepted and dealt with by the sub-centres or the local ganglia. There is the same system of division of labour here as in the social community. In the latter there is a chief centre, and there are also local and provincial centres ; so in the cell community there is a chief centre

and sub-centres, and the chief centre concerns itself as little with purely local matters as does the high court of Parliament with the affairs of the parish vestry. Or we may compare the system of mental division of labour to the relation existing between the premier and his colleagues under responsible government. In this case the cabinet is not only a corporation; it is also a personality. The premier rules with the assistance of his colleagues, who have the management of their own departments. But these colleagues he may transfer from one department to another, or he may dismiss and replace them by others if he thinks proper. His is the synthetic activity which moulds the policy of the cabinet. In the smaller matters of their departments his colleagues act on their own initiative, but in matters of importance the premier is paramount. He is the Ego, the personality, the ruling power.

(2.) On the same principle I explain the origin of organic modifications. These are not the result of physical causes, as Darwin supposed, but of psychical laws. The physical conditions are the occasions, not the causes, of organic modifications. Organic changes I conceive to