h greater care in guarding against communicable disease; and to
describe some elementary methods of caring for the sick, which, however
simple, are essential to comfort, and sometimes indeed to ultimate
recovery.

FOR FURTHER READING

A History of Nursing--Dock and Nutting, Volume I.

The Life of Florence Nightingale--Cook.

The Life of Pasteur--Vallery-Radot.

The House on Henry Street--Wald.

Public Health Nursing--Gardner, Part I, Chapters I-III.

Origin and Growth of the Healing Art--Berdoe.

Medical History from the Earliest Times--Withington.

Under the Red Cross Flag--Boardman.

Report on National Vitality--Fisher, (Bulletin 30 of the Committee of
One Hundred on National Health. Government Printing Office, Washington).

CHAPTER I

CAUSES AND PREVENTION OF SICKNESS

Diseases of two kinds have long been recognized: first, those
transmitted directly or indirectly from person to person, like smallpox,
measles, and typhoid fever; and second, diseases like heart disease and
apoplexy, which are not so transmitted. These two classes are popularly
called "catching" and "not catching;" the former are the infectious or
communicable diseases, and the latter the non-infectious or
non-communicable. The term contagious, formerly applied to diseases
supposed to be spread only by direct contact, is no longer an accurate
or useful term.

THE COMMUNICABLE DISEASES

The invention of the microscope, as we have seen, revealed the existence
of innumerable little plants and animals, so small that even many
millions crowded together are invisible to the naked eye. These tiny
living creatures are called micro-organisms or germs. The plant forms
are called bacteria (singular, bacterium), and the animal forms
protozoa (singular, protozoon). The common belief that all or even most
bacteria are harmful is quite unfounded. As a matter of fact, while not
less than 1500 different kinds of micro-organisms or germs are known,
only about 75 varieties are known to produce disease.

Most bacteria belong to the class of micro-organisms called saprophytes,
which find their food in dead organic matter, both animal and vegetable,
and cannot flourish in living tissues. These saprophytes act upon the
tissues of dead animals and vegetables, and resolve them into simpler
substances, which are then ready to serve as nourishment for plants
higher in the vegetable kingdom. Thus the processes which we know as
fermentation and put