can be influenced by thought; we have always known vaguely that a man's digestion may be spoiled by worry or bad temper and that merriment is hygienic at meal-times, and we have known quite definitely that fear can upset the routine of the intestines. But now we are told that thought normally promotes the action of the stomach in the habitual process of digestion. It has been ascertained that when food is put before one, the stomach then and there begins to prepare the juices for its digestion: the mere concept of food in the overmind causes the stomach to get to work before ever the food has been taken. Here then we have a necessary subconscious process normally inaugurated by the overmind.

Co-operation of all Three Levels

Does this unity between the lowest and the highest levels exist also between them and the intermediate level? In other words, are we to exclude from our conception that higher psychic region of the undermind, which memory, dreams, and hypnotism tell us of? Physiology shows that we certainly cannot; for the stimuli of the cortex must pass through the mid-brain before reaching the spinal cord and sympathetic. We are, therefore, still safe in classing these diverse phenomena together as part of the subconscious self.

And do we not, as a matter of fact, find all three levels concerned in the commonest actions? Take any ordinary exercise of the motor-nerves. I make

a step forward, for instance. Here is an act of the overmind which wills the step-gives the order:

here also is an act of the lower lever, which contracts the necessary muscles. I do not know in the least how I am doing it; were it not for the researches of the anatomist I should not know that I do contract muscles at all. That is the secret of the lower level, where precisely the right nerve-fibres are stimulated in precisely the right amount to cause the precise required contraction in the muscles where they end.

But is that all? Certainly not. This art of walking I once learnt by many weeks of practice — and how difficult it is to adjust the muscles so as to balance the body those people can realise who have learnt to bicycle, which is a much easier acquirement than walking. Somewhere in the undermind I have stored up the memories or the habits that I acquired in my childish practice. When I was a baby I could only kick my legs aimlessly. I had no conscious control of them; then as the legs grew stronger my overmind desired to walk, but I could not walk properly until, after many tumbles, I had passed the experience of the overmind into the subconscious region, and then I could walk without thinking about it. So now when I take a step, all three levels co-operate: my overmind gives the order, the middle level by the acquired habit co-relates various motor-nerves in arms and head and trunk and legs, and in the lower level the nerves are contracted.

Thus we learn to play any game, and thus we acquire all the arts of life. We pass down into the undermind things which once needed all our thought, and we are able to give our attention to something

else. I do not know how I am forming the letters as I write, but once that was a process which required all my attention and was then but ill done: now my undermind attends to it, and I am able to think of what I am writing about, but all the while the muscles of my fingers are being stimulated down in the lower level, where also my respiration, and, I hope, the rest of my functions, are being properly attended to.

We need hardly pursue these illustrations any farther. We need hardly point out that a pianist who talks when he plays is using the three levels in three distinct ways, all the difficult process of playing being taken over by the middle brain; or that the familiar maxim of golf, "keep your eye on the ball,” is really a psychological device for securing the control of the overmind at the moment when the three levels are concentrated into one common effort.

CHAPTER VII

THE CELLS

HITHERTO We have assumed that there is only mind where there are nerves, and that the neurons are the lowest units of intelligence. This was all we needed to show the universal action of mind in the body; and the discovery of the complete unification of the nervous system has made it sufficiently portentous.

But we should not be true to the facts if we stopped here. Other modern discoveries oblige us to take a step further, and to say something about the cells of which the body is composed and which for the sake of clearness we have not mentioned until now. The body is made up of millions upon millions of microscopic specks of protoplasm called cells, and these cells are themselves living creatures — in some subordinate sense they are endowed with some sort of mind. Thus there can be mind even without any nerves. A single undifferentiated cell has a psychology: it is a "nucleated mass of protoplasm endowed with the attributes of life," 1 and in it we have the beginnings of mind -" psychological phenomena begin among the very lowest class of beings; they are met with in every form of life, from

1 A. A. Böhm, M. von Davidoff, Text-book of Histology, Ed. by Dr. K. Huher, 2nd ed., 1904, p. 58 and passim.

the simplest cellule to the most complicated organism."

We can see this quite clearly if we look at those minute living creatures outside the body, which consist of one cell only and maintain an independent life the unicellular organisms as they are called. There are countless multitudes of such creatures, each a mere speck of protoplasm, a single cell, having neither nerves, mouth, stomach, nor any organs whatever. Yet these creatures have that sort of mind which we call instinct. Binet 2 has shown that one-celled organisms have the following powers

1. The perception of the external object.

2. The choice made between a number of objects. 3. The perception of their position in space. 4. Movements calculated either to approach the body and seize it, or to flee from it.

There is a wide variety of character in such microbes. Some live in one way, some in another; some make to themselves shells of one pattern, some of another, most make no shells at all; some are little animals, others are little vegetables; some are rod-shaped, and are called bacilli, some cork-screw shaped, and are called spirilla, some are round; some breed poisons, causing the most terrible diseases, and are called pathogenic, some are perfectly harmless, some are exceedingly beneficial. But microbes of this kind are alike individualists.

1 A. Binet, La Vie Psychique des Micro-organismes. See Preface to the American edition (T. T. McCormack, 1889), written by the author.

2 La Vie Psychique des Micro-organismes, p. 61.