Hygienic Physiology | Page 3

at little expense
of valuable school time.

The Introduction is designed merely to furnish suggestive material for
the first lesson, preparatory to beginning the study. Other subjects for
consideration may be found in the section on Health and Disease, in the
Selected Readings, and among the questions given in the Appendix.
Where time will allow, the Selected Readings may profitably be used in
connection with the topics to which they relate. Questions upon them
are so incorporated with those upon the text proper that they may be
employed or not, according to the judgment of the teacher.
NOTE.--Interest in the study of Physiology will be much increased by
the use of the microscope and prepared slides. These may be obtained
from any good optician.
INTRODUCTION.
Physiological study in youth is of inestimable value. Precious lives are
frequently lost through ignorance. Thousands squander in early years
the strength which should have been kept for the work of real life.
Habits are often formed in youth which entail weakness and poverty
upon manhood, and are a cause of lifelong regret. The use of a strained
limb may permanently damage it. Some silly feat of strength may
produce an irreparable injury. A thoughtless hour of reading by twilight
may impair the sight for life. A terrible accident may happen, and a
dear friend perish before our eyes, while we stand by powerless to
render the assistance we could so easily give did we "only know what
to do." The thousand little hints which may save or lengthen life, may
repel or abate disease, and the simple laws which regulate our bodily
vigor, should be so familiar that we may be quick to apply them in an
emergency. The preservation of health is easier than the cure of disease.
Childhood can not afford to wait for the lesson of experience which is
learned only when the penalty of violated law has been already incurred,
and health irrevocably lost.
NATURE'S LAWS INVIOLABLE.--In infancy, we learn how terribly
Nature punishes a violation of certain laws, and how promptly she
applies the penalty. We soon find out the peril of fire, falls, edged tools,
and the like. We fail, however, to notice the equally sharp and certain
punishments which bad habits entail. We are quick to feel the need of

food, but not so ready to perceive the danger of an excess. A lack of air
drives us at once to secure a supply; foul air is as fatal, but it gives us
no warning.
Nature provides a little training for us at the outset of life, but leaves
the most for us to learn by bitter experience. So in youth we throw
away our strength as if it were a burden of which we desire to be rid.
We eat anything, and at any time; do anything we please, and sit up any
number of nights with little or no sleep. Because we feel only a
momentary discomfort from these physical sins, we fondly imagine
when that is gone we are all right again. Our drafts upon our
constitution are promptly paid, and we expect this will always be the
case; but some day they will come back to us, protested; Nature will
refuse to meet our demands, and we shall find ourselves physical
bankrupts.
We are furnished in the beginning with a certain vital force upon which
we may draw. We can be spendthrifts and waste it in youth, or be wise
and so husband it till manhood. Our shortcomings are all charged
against this stock. Nature's memory never fails; she keeps her account
with perfect exactness. Every physical sin subtracts from the sum and
strength of our years. We may cure a disease, but it never leaves us as it
found us. We may heal a wound, but the scar still shows. We reap as
we sow, and we may either gather in the thorns, one by one, to torment
and destroy, or we may rejoice in the happy harvest of a hale old age.

I.
THE SKELETON.
"Not in the World of Light alone, Where God has built His blazing
throne, Nor yet alone on earth below, With belted seas that come and
go, And endless isles of sunlit green Is all thy Maker's glory seen--
Look in upon thy wondrous frame, Eternal wisdom still the same!"
HOLMES.

ANALYSIS OF THE SKELETON.
NOTE.--The following Table of 206 bones is exclusive of the 8
sesamoid bones which occur in pairs at the roots of the thumb and great
toe, making 214 as given by Leidy and Draper. Gray omits the bones of
the ear, and names 200 as the total number.
THE SKELETON. _ | I. THE HEAD (28 bones.) | _ | | Frontal Bone
(forehead). | _ | Two Parietal Bones. | | 1.