secure some conception of it and thus will be able better to control

the mental processes which it underlies.



To the naked eye the brain is a large jelly-like mass enclosed in a

bony covering, about one-fourth of an inch thick, called the skull.

Inside the skull it is protected by a thick membrane. At its base

emerges the spinal cord, a long strand of nerve fibers extending down

the spine. For most of its length, the cord is about as large around as

your little finger, but it tapers at the lower end. From it at right

angles throughout its length branch out thirty-one pairs of fibrous

nerves which radiate to all parts of the body. The brain and spinal

cord, with all its ramifications, are known as the nervous system. You

see now that, though we started with the statement that the mind is

intimately connected with the brain, we must now enlarge our statement

and say it is connected with the entire nervous system. It is therefore

to the nervous system that we must turn our attention.



Although to the naked eye the nervous system is apparently made up of a

number of different kinds of material, still we see, when we turn our

microscopes upon it, that its parts are structurally the same. Reduced

to lowest terms, the nervous system is found to be composed of minute

units of structure called nerve-cells or neurones. Each of these looks

like a string frayed out at both ends, with a bulge somewhere along its

length. The nervous system is made up of millions of these little cells

packed together in various combinations and distributed throughout the

body. Some of the neurones are as long as three feet; others measure

but a fraction of an inch in length.



We do not know exactly how the mind, that part of us which feels,

reasons and wills, is connected with this mass of cells called the

nervous system. We do know, however, that every time anything occurs in

the mind, there is a change in some part of the nervous system.

Applying this fact to study, it is obvious that when you are performing

any of the operations of study, memorizing foreign vocabularies, making

arithmetical calculations, reasoning out problems in geometry, you are

making changes in your nervous system. The question before us, then,

is, What is the nature of these changes?



According to present knowledge, the action of the nervous system is

best conceived as a form of chemical change that spreads among the

nerve-cells. We call this commotion the nervous current. It is very

rapid, moving faster than one hundred feet a second, and runs along the

cells in much the same way as a "spark runs along a train of

gunpowder." It is important to note that neurones never act singly;

they always act in groups, the nervous current passing from neurone to

neurone. It is thought that the most important changes in the nervous

system do not occur within the individual neurones, but at the points

where they join with each other. This point of connection is called the

synapse and although we do not understand its exact nature, it may well

be pictured as a valve that governs the passage of the nervous current

from neurone to neurone. At time of birth, most of the valves are

closed. Only a few are open, mainly those connected with the vegetative

processes such as breathing and digestion. But as the individual is

played upon by the objects of the environment, the valves open to the

passage of the nervous current. With increased use they become more and

more permeable, and thus learning is the process of making easier the

passage of the nervous current from one neurone to another.



We shall secure further light upon the action of the nervous system if

we examine some of the properties belonging to nerve-cells. The first

one is _impressibility_. Nerve-cells are very sensitive to impressions

from the outside. If you have ever had the dentist touch an exposed

nerve, you know how extreme this sensitivity is. Naturally such a

property is very important in education, for had we not the power to

receive impressions from the outside world we should not be able to

acquire knowledge. We should not even be able to perceive danger and

remove ourselves from harm. "If we compare a man's body to a building,

calling the steel frame-work his skeleton and the furnace and power

station his digestive organs and lungs, the nervous system would

include, with other things, the thermometers, heat regulators, electric

buttons, door-bells, valve-openers,--the parts of the building, in

short, which are specifically designed to respond to influences of the

environment." The second property of nerve-cells which is important in

study is _conductivity_. As soon as a neurone is stimulated at one end,

it communicates its excitement, by means of the nervous current, to the

next neurone or to neighboring neurones. Just as an electric current

might pass along one wire, thence to another, and along it to a third,

so the nervous current passes from neurone to neurone. As might be

expected, the two functions of impressibility and conductivity are

aided by such an arrangement of the nerve-cells that the nervous

current may pass over definitely laid pathways. These systems of

pathways will be described in a later paragraph.



The third property of nerve-cells which is important in study is

_modifiability_. That is, impressions made upon the nerve-cells are

retained. Most living tissue is modifiable to some extent. The features

of the face are modifiable, and if one habitually assumes a peevish

expression, it becomes, after a time, permanently fixed. The nervous

system, however, possesses the power of modifiability to a marked

degree, even a single impression sufficing to make striking

modification. This is very important in study, being the basis for the

retentive powers of the mind.



Having examined the action of the nervous system in its simplicity, we

have now to examine the ways in which the parts of the nervous system

are combined. We shall be helped if we keep to the conception of it as

an aggregation of systems or groups of pathways. Some of these we shall

attempt to trace out. Beginning with those at the outermost parts of

the body, we find them located in the sense-organs, not only within

the traditional five, but also within the muscles, tendons, joints,

and internal organs of the body such as the heart, and digestive

organs. In all these places we find ends of neurones which converge at

the spinal cord and travel to the brain. They are called sensory

neurones and their function is to carry messages inward to the brain.

Thus, the brain represents, in great part, a central receiving station

for impressions from the outside world. The nerve-cells carrying

messages from the various parts of the body terminate in particular

areas. Thus an area in the back part of the brain receives messages

from the eyes; another area near the top of the brain receives messages

from the skin. These areas are quite clearly marked out and may be

studied in detail by means of the accompanying diagram.



There is another large group of nerve-cells which, when traced out, are

found to have one terminal in the brain and the other in the muscles

throughout the body. The area in the brain, where these neurones

emerge, is near the top of the brain in the area marked _Motor_ on the

diagram. From here the fibers travel down through the spinal cord and

out to the muscles. The nerve-cells in this group are called motor

neurones and their function is to carry messages from the brain out to

the muscles, for a muscle ordinarily does not act without a nervous

current to set it off.



So far we have seen that the brain has the two functions of receiving

impressions from the sense-organs and of sending out orders to the

muscles. There is a further mechanism that must now be described. When

messages are received in the sensory areas, it is necessary that there

be some means within the brain of transmitting them over to the motor

area so that they may be acted upon. Such an arrangement is provided by

another group of nerve-cells in the brain, having as their function the

transmission of the nervous current from one area to another. They are

called association neurones and transmit the nervous current from

sensory areas to motor areas or from one sensory area to another. For

example, suppose you see a brick falling from above and you dodge

quickly back. The neural action accompanying this occurrence consists

of an impression upon the nerve-cells in the eye, the conduction of the

nervous current back to the visual area of the brain, the transmission

of the current over association neurones to the motor area, then its

transmission over the motor neurones, down the spinal cord, to the

muscles that enable you to dodge the missile. The association neurones

have the further function of connecting one sensory area in the brain

with another. For example, when you see, smell, taste and touch an

orange, the corresponding areas in the brain act in conjunction and are

associated by means of the association neurones connecting them. The

association neurones play a large part in the securing and organizing

of knowledge. They are very important in study, for all learning

consists in building up associations.



From the foregoing description we see that the nervous system consists

merely of a mechanism for the reception and transmission of incoming

messages and their transformation into outgoing messages which produce

movement. The brain is the center where such transformations are made,

being a sort of central switchboard which permits the sense-organs to

come into communication with muscles. It is also the instrument by

means of which the impressions from the various senses can be united

and experience can be unified. The brain serves further as the medium

whereby impressions once made can be retained. That is, it is the great

organ of memory. Hence we see that it is to this organ we must look for

the performance of the activities necessary to study. Everything that

enters it produces some modification within it. Education consists in a

process of undergoing a selected group of experiences of such a nature

as to leave beneficial results in the brain. By means of the changes

made there, the individual is able better to adjust himself to new

situations. For when the individual enters the world, he is not

prepared to meet many situations; only a few of the neural connections

are made and he is able to perform only a meagre number of simple acts,

such as breathing, crying, digestion. The pathways for complex acts,

such as speaking English or French, or writing, are not formed at birth

but must be built up within the life-time of the individual. It is the

process of building them up that we call education. This process is a

physical feat involving the production of changes in physical material

in the brain. Study involves the overcoming of resistance in the

nervous system. That is why it is so hard. In your early school-days,

when you set about laboriously learning the multiplication table, your

unwilling protests were wrung because you were being compelled to force

the nervous current through new pathways, and to overcome the inertia

of physical matter. Today, when you begin a train of reasoning, the

task is difficult because you are opening hitherto untravelled

pathways. There is a comforting thought, however, which is derived from

the factor of modifiability, in that with each succeeding repetition,

the task becomes easier, because the path becomes worn smoothly and the

nervous current seeks it of its own accord; in other words, each act

and each thought tends to become habitualized. Education is then a

process of forming habits, and the rest of the book will be devoted to

the description and discussion of habits which a student should form.



READING AND EXERCISE



Reading: Herrick (7)



Exercise 1. Draw a picture of the brain, showing roughly what takes

place there (a) when you read a book, (6) listen to a lecture, (c) take

notes.