No matter where you look you will find that every fact in Nature is relatively cause and effect according to the point of view. Thus, if a railroad engine backs into a train of cars it transmits a certain amount of motion to the first car. This imparted motion is again passed on to the next car, and so on. The motion of the first car is, on the one hand, the effect of the impact of the engine, and is, on the other hand, the "cause" of the motion of the second car. And, in general, what is an "effect" in the first car becomes a "cause" when looked at in relation to the second, and what is an "effect" in the second becomes a "cause" in relation to the third. So that even the materialist will agree that "cause" and "effect" are relative terms in dealing with any series of facts in Nature.

A man may be either a spiritualist, believing that the mind is a manifestation of the super-soul, or he may be a materialist, and in either case he may at the same time and with perfect consistency believe, as a practical scientist, that the mind is a "cause" and has bodily action as its "effect."

Naturally this point of view offers no difficulties whatever to the spiritualist. He already looks upon the mind or soul as the "originating cause" of everything.

But the materialist, too, may in accordance with his speculative theory continue to insist that brain-action is the "originating cause" of mental life; yet if the facts show that certain thoughts are invariably followed by certain bodily activities, the materialist may without violence to his theories agree to the great practical value of treating these thoughts as immediate causes, no matter what the history of creation may have been.

Whatever the brand of your materialism or your religious belief, you can join us in accepting this practical-science point of view as a common platform upon which to approach our second fundamental proposition, that "all bodily activity is caused, controlled and directed by the mind."

Ignoring all religious and metaphysical questions, we have, then, to ask ourselves merely:

Can the mind be relied upon to bring about or stop or in any manner influence bodily action? And if it can, what is the extent of the mind's influence?

In answering these questions we shall follow the method of the practical scientist, whose method is invariably the same whatever the problem he is investigating.

This method involves two steps: first, the collection and classification of facts; second, the deduction from those facts of general principles.

The scientist first gathers together the greatest possible array of experiential facts and classifies these facts into sequences—that is to say, he gathers together as many instances as he can find in which one given fact follows directly upon the happening of another given fact.

Having done this, he next formulates in broad general terms the common principle that he finds embodied in these many similar sequences.

Such a formula, if there are facts enough to establish it, is what is known as a scientific law. Its value to the world lies in this, that whenever the given fact shall again occur our knowledge of the scientific law will enable us to predict with certainty just what events will follow the occurrence of that fact.

First, then, let us marshal our facts tending to prove that bodily activities are caused by the mind.

INTROSPECTIVE EVIDENCE OF MENTAL MASTERY

CHAPTER IV
INTROSPECTIVE EVIDENCE OF MENTAL MASTERY

The first and most conspicuous evidential fact is voluntary bodily action; that is to say, bodily action resulting from the exercise of the conscious will.

If you will a bodily movement and that movement immediately follows, you are certainly justified in concluding that your mind has caused the bodily movement. Every conscious, voluntary movement that you make, and you are making thousands of them every hour, is a distinct example of mind activity causing bodily action. In fact, the very will to make any bodily movement is itself nothing more nor less than a mental state.

The will to do a thing is simply the belief, the conviction, that the appropriate bodily movement is about to occur. The whole scientific world is agreed on this.

For example, in order to bend your forefinger do you first think it over, then deliberately put forth some special form of energy? Not at all: The very thought of bending the finger, if unhindered by conflicting ideas, is enough to bend it.

Note this general law: The idea of any bodily action tends to produce the action.

This conception of thought as impellent—that is to say, as impelling bodily activity—is of absolutely fundamental importance. The following simple experiments will illustrate its working.

Ask a number of persons to think successively of the letters "B," "O," and "Q." They are not to pronounce the letters, but simply to think hard about the sound of each letter.

Now, as they think of these letters, one after the other, watch closely and you will see their lips move in readiness to pronounce them. There may be some whose lip-movements you will be unable to detect. If so, it will be because your eye is not quick enough or keen enough to follow them in every case.

Have a friend blindfold you and then stand behind you with his hands on your shoulders. While in this position ask him to concentrate his mind upon some object in another part of the house. Yield yourself to the slightest pressure of his hands or arms and you will soon come to the object of which he has been thinking. If he is unfamiliar with the impelling energy of thought, he will charge the result to mind-reading.

The same law is illustrated by a familiar catch. Ask a friend to define the word "spiral." He will find it difficult to express the meaning in words. And nine persons out of ten while groping for appropriate words will unconsciously describe a spiral in the air with the forefinger.

Swing a locket in front of you, holding the end of the chain with both hands. You will soon see that it will swing in harmony with your thoughts. If you think of a circle, it will swing around in a circle. If you think of the movement of a pendulum, the locket will swing back and forth.

These experiments not only illustrate the impelling energy of thought and its power to induce bodily action, but they indicate also that the bodily effects of mental action are not limited to bodily movements that are conscious and voluntary.

The fact is, every mental state whether you consider it as involving an act of the will or not, is followed some kind of bodily effect, and every bodily action is preceded by some distinct kind of mental activity. From the practical science point of view every thought causes its particular bodily effects.

This is true of simple sensations. It is true of impulses, ideas and emotions. It is true of pleasures and pains. It is true of conscious mental activity. It is true of unconscious mental activity. It is true of the whole range of mental life.

Since the mental conditions that produce bodily effects are not limited to those mental conditions in which there is a conscious exercise of the will, it follows that the bodily effects produced by mental action are not limited to movements of what are known as the voluntary muscles.

On the contrary, they include changes and movements in all of the so-called involuntary muscles, and in every kind of bodily structure. They include changes and movements in every part of the physical organism, from changes in the action of heart, lungs, stomach, liver and other viscera, to changes in the secretions of glands and in the caliber of the tiniest blood-vessels. A few instances such as are familiar to the introspective experience of everyone will illustrate the scope of the mind's control over the body.

Emotion always causes numerous and intense bodily effects. Furious anger may cause frowning brows, grinding teeth, contracted jaws, clenched fists, panting breath, growling cries, bright redness of the face or sudden paleness. None of these effects is voluntary; we may not even be conscious of them.

Fright may produce a wild beating of the heart, a death-like pallor, a gasping motion of the lips, an uncovering or protruding of the eye-balls, a sudden rigidity of the body as if "rooted" to the spot.

Grief may cause profuse secretion of tears, swollen, reddened face, red eyes and other familiar symptoms.

Shame may cause that sudden dilation of the capillary blood-vessels of the face known as "blushing."

The sight of others laughing or yawning makes us laugh or yawn. The sound of one man coughing will become epidemic in an audience. The thought of a sizzling porter-house steak with mushrooms, baked potatoes and rich gravy makes the mouth of a hungry man "water."

Suppose I show you a lemon cut in half and tell you with a wry face and puckered mouth that I am going to suck the juice of this exceedingly sour lemon. As you merely read these lines you may observe that the glands in your mouth have begun to secrete saliva. There is a story of a man who wagered with a friend that he could stop a band that was playing in front of his office. He got three lemons and gave half of a lemon to each of a number of street urchins. He then had these boys walk round and round the band, sucking the lemons and making puckered faces at the musicians. That soon ended the music.

A distinguished German scientist, named Pavlov, has recently demonstrated in a series of experiments with dogs that the sight of the plate that ordinarily bears their food, or the sight of the chair upon which the plate ordinarily stands, or even the sight of the person who commonly brings the plate, may cause the saliva to flow from their salivary glands just as effectively as the food itself would do if placed in their mouths.

There was a time, and that not long ago, when the contact of food with the lining of the stomach was supposed to be the immediate cause of the secretion of the digestive fluids. Yet recent observation of the interior of the stomach through an incision in the body, has shown that just as soon as the food is tasted in the mouth, a purely mental process, the stomach begins to well forth those fluids that are suitable for digestion.

The press recently contained an account of a motorcycle race in Newark, New Jersey. The scene was a great bowl-shaped motor-drome. In the midst of cheering thousands, when riding at the blinding speed of ninety-two miles an hour, the motorcycle of one of the contestants went wrong. It climbed the twenty-eight-foot incline, hurled its rider to instant death and crashed into the packed grandstand. Before the whirling mass of steel was halted by a deep-set iron pillar four men lay dead and twenty-two others unconscious and severely injured. Then the twisted engine of death rebounded from the post and rolled down the saucer-rim of the track.

Around the circular path, his speed scarcely less than that of his ill-fated rival, knowing nothing of the tragedy, hearing nothing of the screams of warning from the crowd, came another racer. The frightened throng saw the coming of a second tragedy. The sound that came from the crowd was a low moaning, a sighing, impotent, unconscious prayer of the thousands for the mercy that could not come. The second motorcycle struck the wreck, leaped into the air, and the body of its rider shot fifty feet over the handlebars and fell at the bottom of the track unconscious. Two hours later he was dead.

What was the effect of this dreadful spectacle upon the onlookers? Confusion, cries of fright and panic, while throughout the grandstand women fainted and lay here and there unconscious. Many were afflicted with nausea. With others the muscles of speech contracted convulsively, knees gave way, hearts "stopped beating." Observe that these were wholly the effects of mental action, effects of sight and sound sensations.

Why multiply instances? All that you need to do to be satisfied that the mind is directly responsible for any and every kind of bodily activity is to examine your own experiences and those of your friends. They will afford you innumerable illustrations.

You will find that not only is your body constantly doing things because your mind wills that it should do them, but that your body is incessantly doing things simply because they are the expression of a passing thought.

The law that Every idea tends to express itself in some form of bodily activity, is one of the most obviously demonstrable principles of human life.

Bear in mind that this is but another way of expressing the second of our first two fundamental principles of mental efficiency, and that we are engaged in a scientific demonstration of its truth so that you will not confuse it with mere theory or speculation.

To recall these fundamental principles to your mind and further impress them upon you, we will restate them:

I. All human achievement comes about through some form of bodily activity.

II. All bodily activity is caused, controlled and directed by the mind.

PHYSIOLOGICAL EVIDENCE OF MENTAL MASTERY

CHAPTER V
PHYSIOLOGICAL EVIDENCE OF MENTAL MASTERY

We have been considering the relationship between mind and body from the standpoint of the mind. Our investigation has been largely introspective; that is to say, we simply looked within ourselves and considered the effects of our mental operations upon our own bodies. The facts we had before us were facts of which we had direct knowledge. We did not have to go out and seek them in the mental and bodily activities of other persons. We found them here within ourselves, inherent in our consciousness. To observe them we had merely to turn the spotlight into the hidden channels of our own minds.

We come now to examine the mind's influence upon the body from the standpoint of the body. To do this we must go forth and investigate. We must use eye, ear and hand. We must use the forceps and scalpel and microscope of the anatomist and physiologist.

But it is well worth while that we should do this. For our investigation will show a bodily structure peculiarly adapted to control by a governing consciousness. It will reveal to the eye a physical mechanism peculiarly fitted for the dissemination of intelligence throughout the body. And, most of all, it will disclose the existence within the body of subordinate mental units, each capable of receiving, understanding and acting upon the intelligence thus submitted. And we shall have strongly corroborative evidence of the mind's complete control over every function of the body.

Examine a green plant and you will observe that it is composed of numerous parts, each of which has some special function to perform. The roots absorb food and drink from the soil. The leaves breathe in carbonic acid from the air and transform it into the living substance of the plant. Every plant has, therefore, an anatomical structure, its parts and tissues visible to the naked eye.

Put one of these tissues under a microscope and you will find that it consists of a honeycomb of small compartments or units. These compartments are called "cells," and the structure of all plant tissues is described as "cellular." Wherever you may look in any plant, you will find these cells making up its tissues. The activity of any part or tissue of the plant, and consequently all of the activities of the plant as a whole, are but the combined and co-operating activities of the various individual cells of which the tissues are composed. The living cell, therefore, is at the basis of all plant life.

In the same way, if you turn to the structure of any animal, you will find that it is composed of parts or organs made up of different kinds of tissues, and these tissues examined under a microscope will disclose a cellular structure similar to that exhibited by the plant.

Look where you will among living things, plant or animal, you will find that all are mere assemblages of cellular tissues.

Extend your investigation further, and examine into forms of life so minute that they can be seen only with the most powerful microscope and you will come upon a whole universe of tiny creatures consisting of a single cell.

Indeed, it is a demonstrable fact that these tiny units of life consisting of but a single cell are far more numerous than the forms of life visible to the naked eye. You will have some idea of their size and number when we tell you that millions may live and die and reproduce their kind in a single thimbleful of earth.

Every plant, then, or every animal, whatever its species, however simple or complicated its structure, is in the last analysis either a single cell or a confederated group of cells.

All life, whether it be the life of a single cell or of an unorganized group of cells or of a republic of cells, has as its basis the life of the cell.

For all the animate world, two great principles stand established. First, that every living organism, plant or animal, big or little, develops from a cell, and is itself a composite of cells, and that the cell is the unit of all life. Secondly, that the big and complex organisms have through long ages developed out of simpler forms, the organic life of today being the result of an age-long process of evolution.

What, then, is the cell, and what part has it played in this process of evolution?

To begin with, a cell is visible only through a microscope. A human blood cell is about one-three-thousandth of an inch across, while a bacterial cell may be no more than one-twenty-five-thousandth of an inch in diameter.

Yet, small as it is, the cell exhibits all of the customary phenomena of independent life; that is to say, it nourishes itself, it grows, it reproduces its kind, it moves about, and it feels. It is a living, breathing, feeling, moving, feeding thing.

The term "cell" suggests a walled-in enclosure. This is because it was originally supposed that a confining wall or membrane was an invariable and essential characteristic of cell structure. It is now known, however, that while such a membrane may exist, as it does in most plant cells, it may be lacking, as is the case in most animal cells.

The only absolutely essential parts of the cell are the inner nucleus or kernel and the tiny mass of living jelly surrounding it, called the protoplasm.

The most powerful microscopes disclose in this protoplasm a certain definite structure, a very fine, thread-like network spreading from the nucleus throughout the semi-fluid albuminous protoplasm. It is certainly in line with the broad analogies of life, to suppose that in each cell the nucleus with its network is the brain and nervous system of that individual cell.

All living organisms consist, then simply of cells. Those consisting of but one cell are termed unicellular; those comprising more than one cell are called pluricellular.

The unicellular organism is the unit of life on this earth. Yet tiny and ultimate as it is, every unicellular organism is possessed of an independent and "free living" existence.

To be convinced of this fact, just consider for a moment the scope of development and range of activities of one of these tiny bodies.

"We see, then," says Haeckel, "that it performs all the essential life functions which the entire organism accomplishes. Every one of these little beings grows and feeds itself independently. It assimilates juices from without, absorbing them from the surrounding fluid. Each separate cell is also able to reproduce itself and to increase. This increase generally takes place by simple division, the nucleus parting first, by a contraction round its circumference, into two parts; after which the protoplasm likewise separates into two divisions. The single cell is able to move and creep about; from its outer surface it sends out and draws back again finger-like processes, thereby modifying its form. Finally, the young cell has feeling, and is more or less sensitive. It performs certain movements on the application of chemical and mechanical irritants."

The single living cell moves about in search of food. When food is found it is enveloped in the mass of protoplasm, digested and assimilated.

The single cell has the power of choice, for it refuses to eat what is unwholesome and extends itself mightily to reach that which is nourishing.

Moebius and Gates are convinced that the single cell possesses memory, for having once encountered anything dangerous, it knows enough to avoid it when presented under similar circumstances. And having once found food in a certain place, it will afterwards make a business of looking for it in the same place.

And, finally, Verwörn and Binet have found in a single living cell manifestations of the emotions of surprise and fear and the rudiments of an ability to adapt means to an end.

Let us now consider pluricellular organisms and consider them particularly from the standpoint of organic evolution. The pluricellular organism is nothing more nor less than a later development, a confederated association of unicellular organisms. Mark the development of such an association.

Originally each separate cell performed all the functions of a separate life. The bonds that united it to its fellows were of the most transient character. Gradually the necessities of environment led to a more and more permanent grouping, until at last the bonds of union became indissoluble.

Meanwhile, the great laws of "adaptation" and "heredity," the basic principles of evolution, have been steadily at work, and slowly there has come about a differentiation of cell function, an apportionment among the different cells of the different kinds of labor.

As the result of such differentiation, the pluricellular organism, as it comes ultimately to be evolved, is composed of many different kinds of cells. Each has its special function. Each has its field of labor. Each lives its own individual life. Each reproduces its own kind. Yet all are bound together as elements of the same "cell society" or organized "cell state."

Among pluricellular organisms man is of course supreme. He is the one form of animal life that is most highly differentiated.

Knowing what you now know of microscopic anatomy, you cannot hold to the simple idea that the human body is a single life-unit. This is the naive belief that is everywhere current among men today. Inquire among your own friends and acquaintances and you will find that not one in a thousand realizes that he is, to put it jocularly, singularly plural, that he is in fact an assemblage of individuals.

Not only is the living human body as a whole alive, but "every part of it as large as a pin-point is alive, with a separate and independent life all its own; every part of the brain, lungs, heart, muscles, fat and skin." No man ever has or ever can count the number of these parts or cells, some of which are so minute that it would take thousands in a row to reach an inch.

"Feeling" or "consciousness" is the sum total of the feelings and consciousness of millions of cells, just as an orchestral harmony is a composite of the sounds of all the individual instruments.

In the ancient dawn of evolution, all the cells of the human body were of the same kind. But Nature is everywhere working out problems of economy and efficiency. And, to meet the necessities of environment, there has gradually come about a parceling out among the different cells of the various tasks that all had been previously called upon to perform for the support of the human institution.

This differentiation in kinds of work has gradually brought about corresponding and appropriate changes of structure in the cells themselves, whereby each has become better fitted to perform its part in the sustenance and growth of the body.

When you come to think that these processes of adaptation and heredity in the human body have been going on for countless millions of years, you can readily understand how it is that the human body of today is made up of more than thirty different kinds of cells, each having its special function.

We have muscle cells, with long, thin bodies like pea-pods, who devote their lives to the business of contraction; thin, hair-like connective tissue cells, whose office is to form a tough tissue for binding the parts of the body together; bone cells, a trades-union of masons, whose life work it is to select and assimilate salts of lime for the upkeep of the joints and framework; hair, skin, and nail cells, in various shapes and sizes, all devoting themselves to the protection and ornamentation of the body; gland cells, who give their lives, a force of trained chemists, to the abstraction from the blood of those substances that are needed for digestion; blood cells, crowding their way through the arteries, some making regular deliveries of provisions to the other tenants, some soldierly fellows patrolling their beats to repel invading disease germs, some serving as humble scavengers; liver cells engaged in the menial service of living off the waste of other organs and at the same time converting it into such fluids as are required for digestion; windpipe and lung cells, whose heads are covered with stiff hairs, which the cell throughout its life waves incessantly to and fro; and, lastly, and most important and of greatest interest to us, brain and nerve cells, the brain cells constituting altogether the organ of objective intelligence, the instrument through which we are conscious of the external world, and the nerve cells serving as a living telegraph to relay information, from one part of the body to another, with the "swiftness of thought."

Says one writer, referring to the cells of the inner or true skin: "As we look at them arranged there like a row of bricks, let us remember two things: first, that this row is actually in our skin at this moment; and, secondly, that each cell is a living being—it is born, grows, lives, breathes, eats, works, decays and dies. A gay time of it these youngsters have on the very banks of a stream that is bringing down to them every minute stores of fresh air in the round, red corpuscles of the blood, and a constant stream of suitable food in the serum. But it is not all pleasure, for every one of them is hard at work."

And again, speaking of the cells that line the air-tubes, he says: "The whole interior, then, of the air-tubes resembles nothing so much as a field of corn swayed by the wind to and fro, the principal sweep, however, being always upwards towards the throat. All particles of dust and dirt inhaled drop on this waving forest of hairs, and are gently passed up and from one to another out of the lungs. When we remember that these hairs commenced waving at our birth, and have never for one second ceased since, and will continue to wave a short time after our death, we are once more filled with wonder at the marvels that surround us on every side."

Remarkable confirmatory evidence of the fact that every organ of the body is composed of individual cell intelligences, endowed with an instinctive knowledge of how to perform their special functions, is found in the experiments of Dr. Alexis Carrel, the recipient of the Nobel prize for science for 1912.

Dr. Carrel has taken hearts, stomachs and kidneys out of living animals, and by artificial nourishment has succeeded in keeping them steadily at work digesting foods, and so on, in his laboratory, for months after the death of the bodies from which they were originally taken.

We see, then, that every human body is an exceedingly complex association of units. It is a marvelously correlated and organized community of countless microscopic organisms. It is a sort of cell republic, as to which we may truthfully paraphrase: Life and Union, One and Inseparable.

Every human body is thus made up of countless cellular intelligences, each of which instinctively utilizes ways and means for the performance of its special functions and the reproduction of its kind. These cell intelligences carry on, without the knowledge or volition of our central consciousness—that is to say, subconsciously—the vital operations of the body.

Under normal conditions, conditions of health, each cell does its work without regard to the operations of its neighbors. But in the event of accident or disease, it is called upon to repair the organism. And in this it shows an energy and intelligence that "savor of creative power." With what promptness and vigor the cells apply themselves to heal a cut or mend a broken bone! In such cases all that the physician can do is to establish outward conditions that will favor the co-operative labors of these tiny intelligences.

The conclusion to be drawn from all this is obvious. For, if every individual and ultimate part of the body is a mind organism, it is very apparent that the body as a whole is peculiarly adapted to control and direction by mental influences.

Do not lose sight of the fact that in proving such control we are laying the foundation for a scientific method of achieving practical success in life, since all human achievement comes about through some form of bodily activity.

We assume now your complete acceptance of the following propositions, based as they are upon facts long since discovered and enunciated in standard scientific works:

a. The whole body is composed of cells, each of which is an intelligent entity endowed with mental powers commensurate with its needs.

b. The fact that every cell in the body is a mind cell shows that the body, by the very nature of its component parts, is peculiarly susceptible to mental influence and control.

To these propositions we now append the following:

c. A further examination of the body reveals a central mental organism, the brain, composed of highly differentiated cells whose intelligence, as in the case of other cells, is commensurate with their functions.

d. It reveals also a physical mechanism, the nervous system, peculiarly adapted to the communication of intelligence between the central governing intelligence and the subordinate cells.

e. The existence of this mind organism and this mechanism of intercommunication is additional evidence of the control and direction of bodily activities by mental energy.

The facts to follow will not only demonstrate the truth of these propositions, but will disclose the existence within every one of us of a store of mental energies and activities of which we are entirely unconscious.

The brain constitutes the organ of central governing intelligence, and the nerves are the physical means employed in bodily intercommunication.

Brain and nerves are in other words the physical mechanism employed by the mind to dominate the body.

Single nerve fibers are fine, thread-like cells. They are so small as to be invisible to the naked eye. Some of them are so minute that it would take twenty thousand of them laid side by side to measure an inch. Every nerve fiber in the human body forms one of a series of connecting links between some central nerve cell in the brain or spinal cord on the one hand and some bodily tissue on the other.

All nerves originating in the brain may be divided into two classes according as they carry currents to the brain or from it. Those carrying currents to the brain are called sensory nerves, or nerves of sensation; those carrying currents from the brain are called motor nerves, or nerves of motion.

Among the sensory nerves are the nerves of consciousness; that is, the nerves whereby we receive sense impressions from the external world. These include the nerves of touch, sight, pain, hearing, temperature, taste and smell. Motor nerves are those that carry messages from the brain and spinal cord on the one hand to the muscles on the other. They are the lines along which flash all orders resulting in bodily movements.

Another broad division of nerves is into two great nerve systems. There are the cerebro-spinal system and the sympathetic system. The first, the cerebro-spinal system, includes all the nerves of consciousness and of voluntary action; it includes all nerves running between the brain and spinal cord on the one hand and the voluntary muscles on the other. The second, the sympathetic nerve system, consists of all the nerves of the unconscious or functional life; it therefore includes all nerves running between the brain and sympathetic or involuntary nerve centers on the one hand and the involuntary muscles on the other.

Every bodily movement or function that you can start or stop at will, even to such seemingly unconscious acts as winking, walking, etc., is controlled through the cerebro-spinal system. All other functions of the body, including the great vital processes, such as heart pulsation and digestion, are performed unconsciously, are beyond the direct control of the will, and are governed through the sympathetic nerve system.

It is obvious that the cerebro-spinal nerve system is the organ of consciousness, the apparatus through which the mind exercises its conscious and voluntary control over certain functions of the body. It is equally obvious that the sympathetic system is not under the immediate control of consciousness, is not subject to the will, but is dominated by mental influences that act without, or even contrary to, our conscious will and sometimes without our knowledge.

Yet you are not to understand that these two great nerve systems are entirely distinct in their operations. On the contrary, they are in many respects closely related.

Thus, the heart receives nerves from both centers of government, and besides all this is itself the center of groups of nerve cells. The power by which it beats arises from a ganglionic center within the heart itself, so that the heart will continue to beat apart from the body if it be supplied with fresh blood. But the rapidity of the heart's beating is regulated by the cerebro-spinal and sympathetic systems, of which the former tends to retard the beat and the latter tends to accelerate it.

In the same way, your lungs are governed in part by both centers, for you can breathe slowly or rapidly as you will, but you cannot, by any power of your conscious will, stop breathing altogether.

Your interest in the brain and nerve system is confined to such facts as may prove to be of use to you in your study of the mind. These anatomical divisions interest you only as they are identified with conscious mental action on the one hand and unconscious mental action on the other.

It is, therefore, of no use to you to consider the various divisions of the sympathetic nerve system, since the sympathetic nerve system in its entirety belongs to the field of unconscious mental action. It operates without our knowledge and without our will.

The cerebro-spinal system consists of the spinal cord and the brain. The brain in turn is made up of two principal subdivisions. First, there is the greater or upper brain, called the cerebrum; secondly, there is the lower or smaller brain, called the cerebellum. The cerebrum in turn consists of three parts: the convoluted surface brain, the middle brain and the lower brain. So that in all we have the surface brain, the middle brain, the lower brain and the cerebellum. All these parts consist of masses of brain cells with connecting nerve fibers.

And now, as to the functions of these various parts. Beginning at the lowest one and moving upward, we find first that the spinal cord consists of through lines of nerves running between the brain and the rest of the body. At the same time it contains within itself certain nerve centers that are sufficient for many simple bodily movements. These bodily movements are such as are instinctive or habitual and require no distinct act of the will for their performance. They are mere "reactions," without conscious, volitional impulse.

Moving up one step higher, we find that the cerebellum is the organ of equilibrium, and that it as well as the spinal cord operates independently of the conscious will, for no conscious effort of the will is required to make one reel from dizziness.

As to the divisions of the greater brain or cerebrum, we want you to note that the lower brain serves a double purpose. First, it is the channel through which pass through lines of communication to and from the upper brain and the mid-brain on the one hand and the rest of the body on the other. Secondly, it is itself a central office for the maintenance of certain vital functions, such as lung-breathing, heart-beating, saliva-secreting, swallowing, etc., all involuntary and unconscious in the sense that consciousness is not necessary to their performance.

The next higher division, or mid-brain, is a large region from which the conscious will issues its edicts regulating all voluntary bodily movements. It is also the seat of certain special senses, such as sight.

Lastly, the surface brain, known as the cortex, is the interpretative and reflective center, the abode of memory, intellect and will.