l for the
individual, partly out of public spirit, partly in self-defense, to have
some idea of the other important branches, namely, public hygiene, the
hygiene practised by the health officer, semipublic hygiene, the hygiene
of schools, institutions, and industrial establishments, and race
hygiene or eugenics, the most important of all.

All these branches are so closely related that it is impossible to mark
any exact dividing-line. But, in a general way, there is a broad
distinction between eugenics, which is the hygiene of future
generations, and the other two, which relate to the present generation,
as also between these two themselves. Thus public hygiene is that which
is practised by the government for its citizens, while individual
hygiene is that which is practised by the citizens for themselves.
Public hygiene consists chiefly in efforts by the government to
maintain a wholesome environment in which to live, including good
outdoor air--without smoke or foul odors--clean streets, pure water,
good sewers, quarantine, and legal regulations concerning houses,
schools, prisons, hospitals, and other public institutions, foods sold
in markets, and conditions of employment. It is chiefly useful in
preventing _acute_ or infectious diseases, such as typhoid fever,
scarlet fever, measles, whooping-cough, small-pox, yellow fever, and
diphtheria, and in preventing accidents and occupational diseases.
Individual hygiene is chiefly useful in preventing the _chronic_ or
degenerative diseases, that is, diseases of nutrition and of
circulation, such as heart and kidney affections, nervous prostration,
insanity.

Public hygiene has made much progress during recent years. In
consequence, the number of deaths from the acute or infectious diseases
has been greatly diminished. Health officers are beginning to
demonstrate the truth of Pasteur's words, "It is within the power of man
to rid himself of every parasitic disease."

It is this work which has reduced the general death-rate in civilized
countries and sometimes cut it in two, as at Panama. The United States
Public Health Service, on invitation of the Peruvian Government,
recently cut the death-rate in two in one of Peru's disease-ridden
cities.

Individual hygiene, on the other hand, has been greatly neglected,
especially in the United States, and, doubtless largely as a
consequence, the death-rates from the chronic or degenerative diseases
are increasing rapidly. A furt