Official proceedings of the annual meeting: 1923

TRANSITION FROM NEGATIVE TO POSITIVE-BROWN

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Demonic theory.-The earliest theories of disease were found among the savages.
They interpreted fever, sickness, pain, and madness to be due to the occupancy of the
affected body by an evil spirit or demon. Savage therapeutics accurately followed
savage pathology. Demons were cast out by exhortations or drums. They even
practiced "preventive medicine" by means of charms and amulets. We have survivals today in the horseshoe, the rabbit's foot, the horsechestnut, which are carried for
their charm.
Humoral theory.-Hippocrates, the father of medicine, clearly recognized disease as
being a process governed by natural laws. He taught that the body contained four
humors: blood, phlegm, yellow bile, and black bile, a right proportion and mixture of
which constituted health; an improper proportion and irregular distribution, disease.
This theory has never ceased to influence medical thought and practice. It had the
merit of fixing attention upon natural rather than supernatural causes, upon the patient
rather than demons.
Physical and mechanical theories.-There was a great shifting of opinion as to the
true causes of disease between the time of Hippocrates (500 B.C.) and Sydenham (I644 -I689). This period witnessed great advances in anatomy and physiology, which led
in the eighteenth century to the establishment of our physical and mechanical theories
of disease, upon which modern pathology stands.
Germ theory.-The germ theory of disease grew out of the brilliant investigations
of Louis Pasteur. Enticed away from his laboratory by the French government to
investigate diseases of animals, he laid the foundation upon which has been built all of
our modern methods for the control of communicable diseases. Pasteur, whose centenary we celebrate this year, may well be called the "Father of Public Health."
The Evolution of the Modern Public-Health Movement.-Stirred by the discoveries
of Pasteur, the whole attack upon disease began to assume new aspects. It was a short
step from animals to human beings. The world was soon startled by the announcement that Koch had discovered the cause of tuberculosis. This, as you know, was only
the beginning of a long series of brilliant discoveries which have furnished us our most
valuable weapons in the battle against disease.
The underlying legal principles which have been used in the application of these
scientific discoveries to the public-health movement have been defined by President
Goodnow. Dr. Kelley has described the development of the administrative machinery
that has made possible the remarkable advances which have been made during the last
century. It is my privilege to call your attention to certain tendencies in the field of
public health which appear to have unusual significance. I refer to the transition from
the negative to the positive phase. Or it might be better described as our discovery
of the importance of health promotion as a factor in disease prevention. Progress in
the rational control of disease dates from the establishment of the germ theory based
upon the researches of Pasteur. As the field of bacteriology has gradually broadened,
we have roughly classified sickness as communicable and non-communicable. This
classification based upon the known causes of disease has been the guiding factor in
our public-health efforts.
Three well-marked stages may be distinguished in the evolution of the modern
public-health movement. They are suppression of disease; prevention of disease;
and promotion of health.