_domestic_, when applied to a small group of people, as the family; and
public, or _general_, when applied to the community as a whole or to the
race.

*The 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