Studies in the Osteopathic
Basic Principles: Volume
Louisa Burns, M.S., D.O., D.Sc.O.
THE NORMAL BODY HAS A HABIT OF HEALTH.
forms of malfunction are prevented by what, for want of better term, we
are calling “the habit of health.” By this expression is simply meant
that property of living cells which enables them to retain their characteristic
metabolism for a time in the presence of abnormal conditions. Through
centuries of progressive reactions to similar environal changes, the cell
has acquired a certain conservatism in the rhythm of the metabolic changes
which have persisted for so long a time. This conservatism, this
fixity, this persistence in the straight and narrow path of inherited rectitude
is what we are calling “the habit of health.” The term is not
altogether satisfactory, yet it is the best which has been suggested.
habit of health persists in the simplest types of cells. If we may
employ the terms of Ehrlich’s side chain theory in this discussion, we
may say that the habits of the cell, whether of health or disease, are
the functions of the affinities of the side chains of its molecules.
side chains of the living molecule have affinities for certain food stuffs,
etc., which are always found in the normal environment of the cell.
The molecules or radicals which are attached to the side chains satisfy
the affinities of the chains for a time, and are variously used by the
cell either as a source of energy, or as material for building or rebuilding
cell structure. If the substances for which the side chains have
especial affinities are lacking in the environment, these affinities may
be satisfied by other compounds and radicals chemically similar to the
normal foods. If these related substances are essentially like the
normal foods, no harm is done by the change. If there has been present
in the environment more than one element of possible food value, a choice
is proposed to the side chains.
it be granted, for sake of clearness, that there are two slightly different
substances present in the environment of a cell, neither of which is the
food stuff normal to the cell, which is lacking. Some of the side
chains of the molecules of the cell will unite with each of these compounds,
in all probability.
The Beginning of Adaptation.
side chain unites with a radical or molecule which we will call “A,” the
other with the radical or molecule which we will call “B.” The side
chains whose affinities have been satisfied by “A” and “B” have certain
duties to perform in the cell metabolism. These duties or functions
are somewhat modified by the presence of “A” and “B” instead of the normal
food stuffs. If this modification is such as maintains or increases
the rapidity or the efficiency of the functions of the side chain which
has united with the radical “A” and is such as decreases the efficiency
or the rapidity of the action of the side chain which has united with “B,”
then “A” is more quickly used in energy formation or tissue building than
“B.” The side chain which has grasped “A” has then free valencies
again. The same quality or position which rendered this side chain
more liable to unite with “A” in the first instance is very apt to facilitate
its second union with a molecule of the “A” type.
use of “A” instead of the normal food stuffs exerts an influence upon the
side chain with which it is united. This change in the function of
the side chain affects the rapidity and the efficiency and the quality
of the katabolism and the katabolic products of the entire living molecule,
and, through these, of the cell of which these molecules are a part.
This change in the cellular metabolism is the first step toward adaptation.
During the time of the series of changing periods of free valencies and
of satisfaction on the part of the side chain, the affinities are still
most strong for the food stuffs originally normal to the cell, but after
a time, when the series of chemical changes which make up metabolism have
been many times repeated the affinities of the side chain are for the molecule
or radical “A.” The food stuffs originally normal are then foreign
side chain which has united with “B,” the one whose function in the metabolism
of the cell was somewhat retarded by its unlucky union, is rendered more
or less inert by the presence of “B,” or it may be that “B” is more or
less toxic to the chain or to the cell, and destruction or death results.
But there is some reason to believe that side chains whose affinities have
been satisfied in a manner poorly adapted to the ultimate good of the cell
are simply discarded, and are eliminated from the body of the cell as waste
matter. These discarded side chains are sometimes of value to complex
organisms in the presence of infection.
living molecule persists in the rhythm and the affinities to which it has
been accustomed, and this persistency is the habit of health which often
preserves life in the presence of abnormal surroundings.
have a habit of health which is the sum of the habits of its many and various
constituent molecules. Unicellular organisms are affected by certain
changes in their environment which usually make for the preservation of
the life of the individual. For example, an increased degree of heat
increases the motion of certain motile animals and plants. Lately
many scientists are investigating the various forms of taxis and tropisms.
These reactions all make for the preservation of life, in the long run,
else would they not be.
Habit of the Body.
cells of complex bodies, such as our own, enjoy a habit of health in superlative
degree. The factors already mentioned are effective in these cells
also, and other factors which are dependent upon the many generations of
united living add to the conservatism of cell metabolism, and to the perpetuation
of the rhythm of functional changes which are characteristic of these cells.
The periodicity of hunger, thirst, sleep, of the increase in the amylolytic
power of the saliva, of increased and decreased temperature during the
day, with its concomitant increase and decrease of muscular power, the
occurrence of the growth changes, of puberty and the climacteric, are all
indicative of the power of this inherited rhythm of metabolic changes.
The fact that these rhythms are all susceptible to variations in answer
to environal changes is indicative of the origin of habit in the repetition
of certain recurrent environal changes, and also of the power of living
things to adapt themselves to further variations in their environment.
mental aspect of habit is somewhat aside from this discussion, yet it is
rather closely related with it.
Habit of the Mind.
Habits, in the accepted sense of the word, are almost altogether psychical
in their origin. They are perpetuated, often, without the intervention
of consciousness. The physiology of habit is a very interesting and
the beginning, a habit is a conscious reaction to certain bodily or external
factors. The sensory impulses, whether somatic or visceral, whether
originating in the body or in the environment, are carried to consciousness
and there correlated with one another and with remembered experience.
The motor reaction is carried to the appropriate muscles, and the first
action is performed.
when a nerve impulse is carried over a system of neurons, the threshold
value of that system of neurons is lowered. This renders these neurons
more easily stimulated than they were before, and hence they react to slighter
stimulations than before. If the first reaction is frequently repeated,
the lower centers become so easily irritated that stimuli utterly inefficient
in the beginning are able to initiate the whole series of motor reactions.
The habit is formed when the motor reaction occurs independent of consciousness.
It is not needful to assume that the reaction is performed unconsciously,
but only that consciousness is not involved in deciding the nature of the
the purely psychical standpoint, the same factors are concerned.
Those centers upon the cerebral cortex and in the basal ganglia which are
most frequently used are those which have the lowest liminal value.
These are most easily stimulated by external changes, and these therefore
affect most strongly the nature of the efferent impulses aroused by the
incoming sensory impulse.
frequently occurs that in the presence of poor nutrition, auto-intoxication,
peripheral irritations, and some other abnormal conditions, the neurons
of the cerebral cortex are unable to preserve their normal metabolism.
In such cases, the mentality of the patient is affected in some degree.
There is liable to be an abnormal lowering of the liminal value of the
centers which are phylogenetically the oldest, and the motor reactions
to sensory stimulation are not modified by the considerations of altruism,
delicacy and unselfishness characteristic of the normal mentality of civilized
and cultured people.
A.—“Our habits make ourselves. What a difference is there between
individuals that is not measured by habit,--habit of speech, of manner,
of thought? To every change in our surroundings we give an answer
back, an answer which may be speech, deed or silence, but which is always
determined, or at least modified, by our habits of thought and action.
The manner of this answer is invariably characteristic of ourselves, and
is usually very little more than the manifestation of a habit. By
means of habit, the thought of yesterday governs the action of today, the
decisions of the child modify the gait and the speech of the man, the habits
of our savage grand-parents are shown in the clinching of fists and showing
of teeth in our own anger, the use of the ring in the marriage service,
and the offering of food to our friends, without any regard for their hunger.
persistence of habits through the life of the individual, the family, the
race, even through changing environments which overlay the original habits
with a thousand modifications, renders it extremely probable that there
is some structural basis for their development and perpetuation.
In order to consider a suggested explanation of the formation of habits,
it will be needful to consider for a moment some of the facts already demonstrated
with regard to the structure of nerves and their actions.
brain and other parts of the nervous system are made up of small gray bodies,
irregular in shape, known as neurons, or nerve cells, together with the
tissues which nourish and support them. Each neuron has at least
one long, fine fiber growing from its body, and not more than two.
The strong, white cords called nerves are made up of bundles of these fibers,
each with its own sheath, and all bound firmly together. The neurons
vary greatly in size. It would take about twenty-five thousand of
the bodies of the smaller to make a row an inch long, but others have a
diameter fifty times as great. The fibers growing from the larger
cells may be thirty or even forty inches long. There are hundreds
of millions of neurons within the body. Each of these, like the other
cells of the body, leads its own life, maintaining its own individuality,
yet in a manner dependent upon the rest of the body, as, in a city, the
baker depends upon the miller, the tailor, the teacher, and each of these
depends upon every other. The blood and lymph bring food and oxygen
to the neurons and carry their waste materials away. From this food
the cell builds up its own body, and stores energy for future needs.
granules, first discovered by Nissl, are found within the bodies of neurons.
These represent the storehouse of energy. These granules are of very
complex and unstable composition. Their disintegration liberates
the stored energy very much as the disintegration of gunpowder liberates
energy. The granules are built up by the activities of the neurons
just as the green coloring matter of leaves is built up by the activities
of plant cells. The Nissl granules are far more complex than the
coloring matter of plants, however. So unstable are these that a
ray of light breaks down the granules of the neurons of the retina, a faint
sound causes the disintegration of the granules of the neurons within the
ear, the most delicate touch upon the end of the fiber growing from the
neurons near the spinal cord to the tip of the finger breaks down the granules
within the body of these cells. The energy liberated by the disintegration
of these granules is called a ‘nerve impulse.’ Nerve impulses pass from
one neuron to another through the brain, the spinal cord, and other neuron
systems according to their structural relations.
granules in different parts of the nervous system vary greatly in stability.
In neurons rarely used the granules are relatively stable. The frequent
passage of impulses over neurons and neuron systems causes them to build
up granules which are more unstable. That is, the granules of neurons,
like nearly all other complex organic structures, are more easily broken
down when more rapidly built up. All mental development and all training
depend upon this progressive decrease in the stability of the granules
within the neurons.
neurons which receive sensations are arranged in little masses just outside
of the brain and spinal cord. These cells send fibers to all parts
of the body, and by means of these we receive sensations of heat, cold,
pain, touch, weight, sound, smell, taste,--indeed, it is by means of these
cells that we receive knowledge of our own bodies and of the world about
us. Each of these cells sends a second fiber into the spinal cord
or into the lower part of the brain. The fiber branches within the
cord, or the lower part of the brain, sending one division toward the higher
centers and others to the neurons which immediately control the movements
of the body.
neurons which control the movements of the body are called motor cells.
They send fibers to the muscles, and the nerve impulse from a motor cell
causes the shortening of that muscle cell with which its fiber is connected.
These motor cells are found in the spinal cord and in the lower part of
the brain. They are induced to send out nerve impulses to the muscles
by the receipt of impulses from the sensory nerves or from the higher brain
centers. The sensory nerve cells from any part of the body are connected
with the motor cells sending fibers to the muscles moving that part of
when an impulse passes over a certain sensory nerve, it reaches both the
motor nerve cells controlling the muscles of it s own area of the body,
and the higher brain centers where consciousness is affected. At
first, the impulse reaching the motor cell is not sufficient to cause the
liberation of its energy. The impulse carried to the higher brain
centers affects consciousness, i.e., gives the person a knowledge of the
source of the impulse. As a result of this knowledge he sends impulses
through the motor cells which result in appropriate action. The granules
of the motor cells concerned are disintegrated and their energy set free
as a nerve impulse which travels along the nerve fibers to the muscles
whose motion is desired. The motor cells must then build up another
set of granules, must store another fund of potential energy. These
new granules are just a little more rapidly built up than were the old
ones, and are therefore just a little more unstable.
time the original sensation is repeated a part of the impulse from the
sensory cells reaches the corresponding motor cells. If this sensation
is always, or is frequently followed by the passage of impulses from the
higher brain centers to the motor cells, the granules formed by these cells
will become progressively more unstable, until a time will come when the
impulses reaching them from the sensory cells will be sufficient to cause
the liberation of their energy. This energy, or nerve impulse, travels
over the nerve fibers to the muscles, and the movements which result are
those which already have been so often repeated. The original sensation
is carried to the higher brain centers, as before, but since the required
movements have already been performed, attention is less and less vividly
aroused until presently the whole series of events becomes mechanical,--the
habit is formed.
‘short circuits,’ if we may so call them, are formed in many of the lower
nerve centers, but never altogether within the sympathetic system.
The short-circuits which are formed through the spinal cord, or the medulla,
or the mid-brain, are called “reflex actions.” These are inherited
habits,--the short circuits are established at or before birth. Other
short circuits are formed through the cerebellum. By means of these
nerve by-paths we are able to perform very complex coordinated movements
without thought. Walking, dancing, knitting and such handiwork and
dozens of other such complicated actions, at first learned with difficulty,
at last seem almost to do themselves. The Island of Reil, or “speech
center,” affords another opportunity for short circuits. By means
of this by-path, language becomes easy and vigorous.
the result of all these short-circuits, the higher faculties of the brain,
freed from the necessity of attending to the minutiae of routine tasks,
are able to attend the more fully to matters requiring decision.
possibility of the inheritance of acquired habits is one of the puzzles
of our day. At present, there seems to be evidence to justify at
least the tentative supposition that individuals inherit increased or decreased
stability of nerve cells or systems, rather than any mental traits as such.”—From
the Osteopathic World, December, 1905.
Associative processes in the Guinea Pig. Jessie Allen, in The Journal
of Comparative Neurology and Psychology, Vol XIV, No. 4.
in Man and Animals, J. P. Morat, The Physiology of the Nervous System, p. 421,
Edition of 1906.