wish to excel. Its object is not only to improve the health, but to
increase the absolute strength and size of the body, and its effects are
permanent. It necessitates careful diet and constant exercise for a long
period, and proves equally beneficial to both sexes. This book has been
written in vain if the reader has not grasped by now that the activity
of the muscles implies the activity of all the organs in the body.
Accordingly, the whole muscular system is by appropriate methods given
frequent exercise: gentle at first; never exhausting; but constantly
increasing as the strength grows. The result is a general development
of the organs throughout the body, which will in time work a complete
metamorphosis in the individual’s physique.
Yet by strength alone no athlete can excel; success depends upon skill.
He must have the strength to work with, but he must have the knowledge
to apply it without wasting energy, and the ability to do this with
precision. He must practise well the sport he intends to adopt—in other
words, train his central nervous system.
Here, again, we must hark back to the main idea—the unity of the body.
We have already dealt in this essay with the bodily needs in the way of
food and exercise, and we must now consider the needs of its nervous
components. The chief of these is education; but education of the nervous
system means, of course, education of the whole body. There are still
people who cling to the old fallacy that the mind can be developed at the
expense of the body, but a visit to a hospital or a lunatic asylum will
afford many opportunities of seeing how Nature avenges ill-treatment of
‘those delicate tissues wherein the soul transacts its earthly business.’
Physical culture must come before mental: _Mens sana in corpore
sano_—hackneyed, but true.
I do not, of course, say that a man must develop equally both his body
and mind; only, that the former must be functionally competent. The
absurdity of supposing that the brain can benefit by forming part
of an unhealthy body is, surely, obvious to all. Determined invalids
may produce splendid work, as Darwin did, in spite of ill-health, but
not because of it, and men of great mental energy will sometimes wear
themselves out prematurely by their restlessness; but starvation and
maltreatment of the body will not create intellect, however morbidly it
may stimulate the imagination.
Granting the tenement of a healthy body, the education of the central
nervous system must proceed along four distinct lines. A child must learn
useful reflex actions, such as walking; have its association centres
trained, that it may reason quickly and correctly; be endued, if it is
not to live upon a desert island, with a sense of moral responsibility
and ethical principles; and have its head stored with useful facts, from
the meaning of words and the A B C to the value of the coinage.
Few people seem to realize how much a child has to learn before it gets
to the A B C. It begins life with very little beyond a capacity for
learning, and even its sense organs tell it little until it has had
practice in using them. If baby is so unfortunate as to get a scratch
from a pin, he wriggles, and makes the whole house aware of it; but he
does not seem to have a clear idea at all as to where he is hurt. He has
to learn the way about his own body. He passes his hand over his face,
and learns that he has features with a definite position and magnitude;
he then waves his arms in the air, and learns that there is such a thing
as empty space; finally, he knocks his knuckles against the edge of his
cradle, and learns that there are other things in existence besides
himself. Of course, his eyes help him considerably to form his ideas of
things, but his eyes tell him nothing until he has learnt how far to
believe them by correcting their impressions by touch. He learns the
properties of matter by experiment, not intuition.
Very interesting experiments have been made upon people who have
been born blind, and to whom sight has been given late in life by an
operation. They generally take some time to appreciate their good
fortune. Things, they say, are all pressed up against their eyes, and
they are afraid to move. Objects with which they have carefully been
made familiar before the operation—wooden spheres, cubes, cones and
prisms—they have been absolutely unable to recognise by sight until they
have handled them. They have mistaken sparrows for tea-cups, and it
is sometimes only after weeks that they have suddenly discovered that
pictures are something more than a mixture of irregular splashes of
colour on a flat surface.
Babies have to learn to interpret what they see in much the same way,
and take longer about it. The child who cries for the moon is probably
not so unreasonable as people think. He focuses his eyes upon the
little, bright, sharply-defined disc, and it appears to him, if not
actually within arm’s length, at any rate near enough to be caught with a
butterfly-net. It is only after he has seen it sink behind a large tree
on the distant horizon that he gathers a vague idea of its real size and
remoteness.
The term ‘physical culture,’ as usually applied, is supposed only to
mean the development of the muscles and viscera; really it only begins
there. After the organs of nutrition have been got into a healthy state
the motor organs are developed. Finally the nervous system should be
trained. Mere muscle will not make even a good runner. He must practise
carefully till he can take his full stride, and do so without wasting
energy by any needless movements. Then he must make the action which his
brain has decided is the most effective for his build the property of
his spinal cord, that in a race he may use his strength economically,
with his thoughts free to deal with the tactics of his opponents and the
peculiarities of the course, or he will not make his supreme effort at
the most advantageous moment. This is only one instance. Many men having
a normal body develop organs of perception, not motion: the musician and
the wine-taster, as well as the juggler and the athlete, are products of
physical culture. Even the philosopher must foster the physical basis of
intellect.
The education of the nervous system goes on all through life; and just as
oft-repeated actions become automatic, so are habits of thought formed
which are almost as regular; in fact, we might almost call them cerebral
reflexes. Without constant exercise, men lose their flexibility of mind
as well as of body.
But we have already passed the boundaries of our subject, and it is time
for us to pull up, lest we trench further upon another science; for the
study of the mind is the province, not of the physiologist, but of the
psychologist.
II.
Notwithstanding the strange powers of protoplasm, and notwithstanding
that these are accumulated and intensified in the body, as we saw in the
last chapter, there are immovable limitations to vital activity.
This is a fact familiar to all. We can trace diminishing vitality through
a series of stages, from slight fatigue right up to death itself. Sleep
is perhaps one of the most interesting, though it is little understood.
During sleep and the hypnotic trance, we know that the cells of the
hemispheres pause in their work and chemically recruit themselves; that
there is an interruption of consciousness; and that changes occur in the
respiratory and circulatory, and, in fact, in most of the functions.
But exactly how these states are induced we do not know. It has been
suggested that during sleep less blood passes through the brain; but this
is unlikely, and still less probable is it that the nerve cells draw in
their processes and shut up like sea-anemones, as another daring theorist
supposed. We can only draw parallels between the cells of the central
nervous system and any others; all need rest.
The simplest unicellular animals, which we have mentioned so often
already, spend their lives in alternate spells of activity and rest. In
the third essay we mentioned briefly the weakening of each successive
response when a muscle, in which tissue fatigue has chiefly been studied,
is stimulated. Before the muscle contracted it contained a form of sugar;
when it is tired the sugar is gone, and has been replaced by the products
of the chemical action by which the energy was evolved. A period of rest
must then follow, for the muscle to be cleansed and replenished. The case
of glands, described in Essay II., is somewhat similar. After the gland
cell has discharged its ferment, it must spend some time secreting a
fresh stock before it is ready to discharge again. In fact, a cell seems
to load itself up with supplies, like a locomotive with coal, and, after
working till the fuel is nearly exhausted, it has to stop to take in more.
All the cells in the body rest at times; even the cells of the heart,
carefully as they are nourished and incessant as their work seems, rest
between each beat, and the cells of the nervous system form no exception.
The brain no less than the body requires periodic rests to renew its
chemical stores, and these rests have to be all the longer, as during
the waking hours the brain works harder and less intermittently than any
other organ. It is only because the brain is the seat of consciousness
and the source of voluntary movements that these phenomena are suspended
during sleep.
Death may seem at first sight a very simple affair, the breaking up of
protoplasm into simpler non-living compounds; but the death of the body
is anything but simple—in fact, it is not always easy to say when the
body is dead. Usually, however, it is considered dead when the central
nervous system has succumbed, though the muscles may continue to live for
several hours.
Death may begin in many ways. The loss of some organs will bring death
only after a considerable time, while the failure of others disturbs its
economy fatally, and causes an almost immediate cessation of the vital
functions. Any interference with the normal conditions of the brain,
heart, or lungs is very dangerous, and it is injury or disease of one of
the three which puts an end to most men’s troubles. If the brain weakens
so that it no longer keeps the heart beating or the muscles, which fill
and empty the lungs, to their duties, the body, for obvious reasons, can
no longer keep up the cycle of changes we call life. On the other hand,
if the lungs cannot oxidize the blood, or the heart drive fresh pabulum
to the brain, that organ collapses immediately, and, if a stream of pure
blood is not quickly restored to it, dies. No return of the circulation
can then restore it; the death of the rest of the animal must follow.
Being the most delicate, the cells of the central nervous system usually
die first, and we then say that the man is dead. So the body may be,
but much of the protoplasm of which it is composed—whole organs, in
fact—remains alive; the muscles will respond to electrical stimulation,
and in case some people may dispute that this is a sign of life, if
pieces of his skin be removed and grafted into another person, they
will grow there, produce hair, and become, in fact, a part of the new
body. This they could not possibly do if they were dead; we cannot endow
inanimate matter with life.
As death creeps on over the tissues, the leucocytes die, and in doing
so form a ferment which solidifies one of the proteids dissolved in
the blood, so that the familiar clotting takes place. By a similar
process certain constituents of the muscles are also clotted, the
muscles stiffening and passing into what is technically, but also pretty
generally, known as rigor mortis. Rigor is said to set in soon after
death if the body is kept in a warm place, or if death has been preceded
by violent exercise; but death in this instance means only the death of
the body. It is at the precise moment that a muscle fibre dies that it
passes into rigor. By keeping it cool, so that the processes of life may
go on slowly, especially if it be in a healthy condition, its death may
be deferred for hours; while, on the other hand, at the end of a severe
and protracted battle, exhausted soldiers sometimes die instantaneously
on being shot, and are found fixed in the position in which the fatal
bullet found them—on their knees, with gun to shoulder, in the act of
firing.
But if the manner of death is not to be lightly dealt with, its causes
are still more obscure. It seems natural enough that people should be
killed by violence or by diseases with an external or septic origin, or
even by one particular organ wearing out and involving the whole body in
the fate of its part. But why should people die of old age? Why should
their vitality ebb till they quietly go out? Life is a mechanical cycle
of changes. For a time even after it has stopped growing, the body
replaces what it wastes, and keeps itself in a condition of equilibrium.
Why, then, without any apparent external cause, does it, after a more or
less circumscribed period, enter into a decline? And, finally, could we,
by taking the proper precautions, delay or prevent old age and death?
In the first place, regarding protoplasm as a chemical structure, why,
if kept under favourable conditions, should it ever break down? We have
no reason to suppose that it need. It is hard to see how the minute
animals, consisting of only one cell, can die of old age, provided that
no injurious influence be brought to bear upon them. When an individual
has grown to a certain size, it divides in two, and each enters upon life
afresh. Why, therefore, should not all the cells of the body continue to
renew their youth?
The reason why the body can only last a certain time, in spite of the
many quacks with recipes for immortality—recipes including such items
as the avoidance of all trouble, worry, or work—must remain a secret
until we know the chemical basis of life. It seems to lie in the cell.
If a unicellular organism, as described above, be placed in a vessel
of sterilized water and left to live alone under otherwise ideal
conditions, it will start dividing and multiplying, as though it meant to
reproduce itself indefinitely. After a time, however, the shoal begins
to deteriorate; each successive generation is feebler than the last, and
eventually all die. If, however, before this happens one of the effete
cells be placed in another vessel with a similar individual derived from
a different ancestor, the two will fuse and form a single fresh animal
with entirely restored vigour, ready to multiply to the same extent as
either of its original ancestors. A few individuals of a different stock
will in this way revivify the whole brood.
There is, therefore, evidently something in the cell which wears out
after it has divided a certain number of times—something which must be
restored by blending with cells of another strain. What this is we do not
know, and perhaps never shall. The most we know is that it seems to be
something inherent in the nucleus, not the main body of protoplasm of the
cell, for some unicellular animals do not fuse, under the circumstances
related above, but exchange only pieces of their nuclei, and yet derive
the advantages of mutually increased vitality. But if we apply the fact
to our conception of the body as a vast colony of cells with a common
origin, we find that it has an important bearing upon the duration of its
life.
The single eggcell which gave rise to our schematic embryo in Diagram
3, Fig. 1, was formed by the fusion of two cells shed by two distinct
animals. How this one cell grows and multiplies by division is roughly
shown in the diagram and those immediately following it; but though the
cells do not separate, but hang together and form a body, it is obvious
that the colony only amounts to a shoal of unicellular organisms, like
that described above as growing weaker with each successive division
unless blended with individuals of a different stock. This cannot be done
in the body; what would become of our individuality even if such a thing
were possible? The body can help to give rise to new bodies, but its own
tissues must wear out, and when the colony of cells is exhausted it must
die. Careful diet and regular habits, the minimum of wear and tear, may
enable the body to run its full term; but they cannot lengthen the lease
of life.
So far only can the physiologist take us. Physiology may teach us how to
develop our powers and economize our strength; it is already beginning to
convert medicine from an art into a science; it will, it is to be hoped,
shortly work a revolution in our at present barbarous ideas of how to
rear and educate children; it may, in short, teach us how to make the
very most of life and die easily; but not until, if ever, it understands
the physical basis of life, and perhaps not even then, will it be likely
to succeed in prolonging a man’s days much beyond the traditional
fourscore years.
CONCLUSION.
While the physiologist is quietly working, making slow but sure
progress, his critics, friendly and otherwise, buzz about him like bees.
There are some who are in a chronic state of excitement, expecting a
revolutionizing discovery from hour to hour; there are others who assure
him that he has reached the limit of human powers of comprehension, and
can never know much more than he does to-day; and, lastly, there are
those who declare that he has done next to nothing, and that his utmost
endeavours have failed to effect any real result, and leave all the
important secrets of life untouched.
No one knows better than the physiologist how mistaken is the
oversanguine class first mentioned. In no department of science,
certainly not in physiology, is it possible to reach the top of the
ladder by a bound; each rung must be mastered in order. In invading the
unknown land the scientist must thoroughly explore and effectively occupy
as he advances. He must annex as he goes along; the flying columns which
try to reach the enemy’s capital by a dash are never heard of again. In
physiology the publication of the various steps is sometimes withheld
until the objective has been reached, but our knowledge of life is like
Solomon’s temple: a David collects the material, and his successor raises
the edifice. The world watches it grow. It is not like those bewildering
and unstable palaces of the ‘Arabian Nights,’ built by genii in a single
night, and often vanishing as mysteriously.
In every age there have existed people who declare that men can never
know more than they do at the moment. There were plenty of them when the
science of physiology was unborn, and there will be plenty more of them a
hundred years hence; only then they will refer with tolerant amusement to
the crude and elementary ideas of their predecessors at the beginning of
the twentieth century.
The third class, who take such delight in minimizing the achievements
of the physiologist, usually are found, if anyone takes them seriously,
to know very little either about the science of physiology itself or
the history of its growth. I leave the reader to form his own verdict
upon the value of the results obtained from their exceedingly brief and
sketchy description in this little volume, with the remark that the
science is barely more than three-quarters of a century old, and the
most important additions to our knowledge have been made within the last
twenty years.
There were, paradoxical as it may sound, great physiologists before then;
the work of Harvey, who three centuries ago discovered the circulation
of the blood, is above all praise; but how nebulous must have been
their ideas may be seen from the following facts: It was only at the
beginning of the nineteenth century that the atomic theory of matter
was formulated; it was not until twenty years later that the world was
startled by a daring chemist who showed that organic compounds obeyed
the same natural laws as inorganic; and not until ten years later was
the cellular structure of animals, the groundwork in all study of life,
recognised.
Even when the science was set upon firm foundations, progress was
at first necessarily slow: the organic chemist took some time in
examining and classifying the compounds met with in the body—he has not
finished yet; and even when the cell theory was grasped, it required
much ingenuity and long patience to devise ways of examining organs
under the microscope, so that their structure could be made out. The
microscope itself was a poor toy fifty years ago, magnifying a diameter
ten times where now it magnifies a hundred, and giving only a dim and
distorted image. The perfecting of the microscope, and the introduction
of anæsthetics and antiseptics, have led to enormous strides being made
within the last two decades.
The result of the advance in chemical knowledge, and the introduction of
fresh aids to investigation, led to the discarding of vital force as a
working hypothesis. Vital force was the bane of the earlier biologists.
They made it accountable for all they could not understand, and with
this restatement of their difficulties—a restatement which they called
an explanation—refrained from further research. But when it was found
that many of these inexplicable phenomena, though refractory, yielded
to careful study, and could be explained by chemical and physical laws,
the physiologist ceased to say of them, ‘They are problems connected
with Life, and therefore explained by Vital Force, which is past man’s
understanding,’ and frankly admitted that there were many things which he
did not as yet fathom. Recently a vitalistic school has cropped up again,
declaring that all that it cannot understand must infallibly be due to
some occult agency. It shows remarkable vitality in surviving the shocks
of successive discoveries.
Turning once more to the present day, we will conclude with a brief
glance round a physiological laboratory, and see by what methods the
physiologist is preparing future surprises. The chemical department first
claims our attention. The imports and exports of animals are carefully
balanced, and the changes produced in the food examined. The animal is
enclosed in an airtight chamber, air of known composition being pumped
into it, and the air which escapes analyzed. The animal most used for
this experiment is man himself, since he will take rest and exercise
to order, the latter usually on the treadmill, by which it can be also
measured, and can be relied upon not to while away the tedium of his
imprisonment by gnawing holes in the walls or upsetting his food.
All the substances used as food, found in or excreted by the body, are
being thoroughly studied; but it should be remembered that this is
chemistry, not physiology. Physiology is only concerned with protoplasm,
and the physiologist who goes deeply into the chemistry of non-living
matter has to discipline his mind against forgetting its ceaseless
change, and trying to regard it as though it were constant. The actual
chemistry of protoplasm will be a very hard nut to crack, and may
defy us until we can depict molecules as well actually as we now can
symbolically. Some idea of the difficulty may be formed if we consider
that it is impossible to imagine a pure sample. From the restless
activity which is the condition of its existence, it is always working
changes in its surrounding, always mixed with raw material, and always
masked by the products of its own metabolism. Even if we withhold the
former, it consumes its own substance until the moment of death. It does
not even look homogeneous under the microscope.