II
THE BRAIN
WE are accustomed to speak of the brain as the organ of mind, but it is more than that; it is the engine which runs the body--a sort of powerhouse, so to speak. The varied stock of ideas which beat upon it furnishes the fuel. If those ideas are vigorous and numerous, the engine, under normal conditions, works quickly and powerfully; but if they are weak and slow, the fire burns low--the body is sluggish.
The brain, physiologically a ma** of nervous tissue, delicate and sensitive, is divided into two main parts: the cerebrum, the larger and upper, the cerebellum, the smaller, situated below and behind (Fig. 1). The cerebrum consists of an outer zone, the cortex, or gray matter, wherein lie the nerve
FIG. I.--SIDE VIEW OF BRAIN AND UPPER PART OF SPINAL CORD. FIG. I.--SIDE VIEW OF BRAIN AND UPPER PART OF SPINAL CORD.
1. Cerebrum. 3. Medulla Oblongata.
2. Cerebellum. 4. Spinal Cord.
FIG. 2.--THE APPROXIMATE SITUATION OF THE VARIOUS AREAS. FIG. 2.--THE APPROXIMATE SITUATION OF THE VARIOUS AREAS.
1. Sensory Area. 2. Motor Area. 3. Higher Psychical Area.
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cells forming the various centers, and an inner portion, or white substance, which consists of bundles of nerve-fibers leading from the cortical cells and distributed over the entire body. The outer surface is laid in folds or convolutions. The brain is the seat of intelligence, the organ of the conscious mind. It must act before we can take note of what is pa**ing on.
Distributed over that portion of the cortex called the sensory area (Fig. 2) are the centers of sense-perception, which receive, respectively, the impressions of sight, sound, touch, taste, and smell. Another portion is called the motor area (Fig. 2). Here are situated the motor centers which send out over the nerves, stimuli for producing motion. The frontal portion is known as the higher psychical area (Fig. 2). The nerve-cells comprising these three divisions do not work independently, but are a**ociated one with another. No cell
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is isolated, but each is intimately connected with some other cell, or cells, in motor and psychical area. All form part of a complex system. The stimulation of one part brings into action many other parts.
Should I touch a hot iron, the nerves of the skin receive a shock which produces a wave or current, carried along nerve-fibres to the spinal cord, thence to the brain. Pain is felt. I know I have touched a hot iron only after the stimulus has been received by the brain.
No one knows he hears a bell ring or a clock strike until the waves of sound striking the ear-drum are transmitted by the auditory nerves to the center of auditory perception. No one knows he is looking upon the face of a friend until light waves striking the retina of the eye are transmitted by the sight-nerves to the center of sight perception.
With the other parts of the brain we need not concern ourselves. As to its
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structure, we find that it is so sensitive and delicate that the slightest shock will cause a movement of the particles; hence all its various parts are very delicately balanced, it must be evident. They are held in equilibrium, when all is well, by nature, but it is called unstable equilibrium, because the balance is so easily disturbed. When it is permanently disturbed, we say that the person is insane; when only temporarily, we say he is irrational or hysterical.
The psychical area is so intimately connected with the various centers of the other areas, that if it becomes unbalanced, these centers, sympathizing as it were, become unbalanced. For instance, worry may affect digestion and fear may affect motion. Most of us have experienced either one or both of these conditions.
Strong emotions like anger, fear, grief, jealousy, and despair often make temporary maniacs; for they powerfully affect and disturb the equilibrium of the brain.
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A thing so delicate is still the engine which runs the body. One could not make the smallest movement, unless the mind supplied the force of activity. Ideas in action induce a molecular and chemical change which sets free energy not only to act but to keep the internal fires burning.
In order to heat your home you must have fuel, but you must also have a furnace or engine. If you have good fuel and a good engine, you will have a warm house. But suppose that your fuel is poor or scanty, then the fire runs low. On the other hand, suppose that your engine is worn out or poorly constructed--again you will be minus heat.
Just so, if there is a good stock of vigorous ideas there is sufficient force to insure the chemical reactions of the body--keep up the fire--but if the mind-force is weak or scanty, the fire runs low, the body is sluggish. Feeble-minded persons are slow and clumsy in their movements.
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On the other hand, if the brain is debilitated or worn out, again the fire runs low. So it works both ways--no fuel, no fire, or no engine, no fire.
The state of the brain, therefore, must be of equal importance with the state of the mind, as a leading English psychologist intimates when he says: "The primary essentials of health are a sound brain and a buoyant mind."
Finally, if the brain is the engine which runs the body, it must be in communication with all parts; which is true. The brain-centers govern all parts of the body; "every cell of the body has its ultimate representation in a brain-cell," which is its governor or prime mover. Thus, the cells of the stomach are represented by cells in the brain, with which they are connected by nerve-fibers; and hence your indigestion may not be caused by weakness of the stomach-cells, but by debility of the brain-cells which correspond. If the brain-cells do
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not work well, you can hardly expect those of the body to do so--poor engine, poor fire.
Thus we are obliged to conclude that tho we must look to the mind for the force to run the body, we must equally look to the brain as the medium for the manifestation of that force. Nature's alchemy has unvarying laws. The finest, the most vigorous mind can not work effectively through a defective medium. As well try to grow figs of thistles.