Physiology and Hygiene for Secondary Schools | Page 3

General Aim of Hygiene.*--There are many so-called laws of
health, and for these laws it is essential in the management of the body
to find a common basis. This basic law, suggested by the nature of the
body and conditions that affect its well-being, may be termed the Law
of Harmony: The mode of living must harmonize with the plan of the
body. To live properly one must supply the conditions which his body,
on account of its nature and plan, requires. On the other hand, he must
avoid those things and conditions which are injurious, i.e., out of
harmony with the body plan. To secure these results, it is necessary to
determine what is and what is not in harmony with the plan of the body,
and to find the means of applying this knowledge to the everyday
problems of living. Such is the general aim of hygiene. Stated in other

words: Hygiene has for its general aim the bringing about of an
essential harmony between the body and the things and conditions that
affect it.(1)
*Relation of Anatomy and Physiology to the Study of Hygiene.*--If the
chief object in studying the body is that of learning how to manage or
care for it, and hygiene supplies this information, why must we also
study anatomy and physiology? The answer to this question has already
been in part suggested. In order to determine what things and
conditions are in harmony with the plan of the body, we must know
what that plan is. This knowledge is obtained through a study of
anatomy and physiology. The knowledge gained through these subjects
also renders the study of hygiene more interesting and valuable. One is
enabled to see why and how obedience to hygienic laws benefits, and
disobedience to them injures, the body. This causes the teachings of
hygiene to be taken more seriously and renders them more practical. In
short, anatomy and physiology supply a necessary basis for the study of
hygiene.
*Advantages of Properly Managing the Body.*--One result following
the mismanagement of the body is loss of health. But attending the loss
of health are other results which are equally serious and far-reaching.
Without good health, people fail to accomplish their aims and
ambitions in life; they miss the joy of living; they lose their ability to
work and become burdens on their friends or society. The proper
management of the body means health, and it also means the capacity
for work and for enjoyment. Not only should one seek to preserve his
health from day to day, but he should so manage his body as to use his
powers to the best advantage and prolong as far as possible the period
during which he may be a capable and useful citizen.

CHAPTER II
- GENERAL VIEW OF THE BODY
*External Divisions.*--Examined from the outside, the body presents

certain parts, or divisions, familiar to all. The main, or central, portion
is known as the trunk, and to this are attached the head, the upper
extremities, and the lower extremities. These in turn present smaller
divisions which are also familiar. The upper part of the trunk is known
as the thorax, or chest, and the lower part as the abdomen. The portions
of the trunk to which the arms are attached are the shoulders, and those
to which the legs are joined are the hips, while the central rear portion
between the neck and the hips is the back. The fingers, the hand, the
wrist, the forearm, the elbow, and the upper arm are the main divisions
of each of the upper extremities. The toes, the foot, the ankle, the lower
leg, the knee, and the thigh are the chief divisions of each of the lower
extremities. The head, which is joined to the trunk by the neck, has
such interesting parts as the eyes, the ears, the nose, the jaws, the
cheeks, and the mouth. The entire body is inclosed in a double covering,
called the skin, which protects it in various ways.
*The Tissues.*--After examining the external features of the body, we
naturally inquire about its internal structures. These are not so easily
investigated, and much which is of interest to advanced students must
be omitted from an elementary course. We may, however, as a first step
in this study, determine what kinds of materials enter into the
construction of the body. For this purpose the body of some small
animal should be dissected and studied. (See observation at close of
chapter.) The different materials found by such a dissection correspond
closely to the substances, called tissues, which make up the human
body. The main tissues of the body, as ordinarily named, are the
muscular tissue, the osseous tissue, the connective tissue, the nervous
tissue, the adipose tissue, the cartilaginous tissue,