science of medicine all through
succeeding centuries. According to this celebrated theory there are four
humors in the body--blood, phlegm, yellow bile, and black bile. When
these humors are mixed in exact proportions they constitute health;
but any deviations from these proportions produce disease. In treating
diseases the aim of the physician was to discover which of these humors
were out of proportion and to restore them to their natural equilibrium.
It was in the methods employed in this restitution, rather than a
disagreement about the humors themselves, that resulted in the various
"schools" of medicine.

In many ways the surgery of Hippocrates showed a better understanding
of the structure of the organs than of their functions. Some of the
surgical procedures as described by him are followed, with slight
modifications, to-day. Many of his methods were entirely lost sight of
until modern times, and one, the treatment of dislocation of the
outer end of the collar-bone, was not revived until some time in the
eighteenth century.

Hippocrates, it seems, like modern physicians, sometimes suffered
from the ingratitude of his patients. "The physician visits a patient
suffering from fever or a wound, and prescribes for him," he says; "on
the next day, if the patient feels worse the blame is laid upon the
physician; if, on the other hand, he feels better, nature is extolled,
and the physician reaps no praise." The essence of this has been
repeated in rhyme and prose by writers in every age and country, but
the "father of medicine" cautions physicians against allowing it to
influence their attitude towards their profession.

VIII. POST-SOCRATIC SCIENCE AT ATHENS--PLATO, ARISTOTLE, AND
THEOPHRASTUS

Doubtless it has been noticed that our earlier scientists were as far
removed as possible from the limitations of specialism. In point of
fact, in this early day, knowledge had not been classified as it came
to be later on. The philosopher was, as his name implied, a lover of
knowledge, and he did not find it beyond the reach of his capacity to
apply himself to all departments of the field of human investigation. It
is nothing strange to discover that Anaximander and the Pythagoreans
and Anaxagoras have propounded theories regarding the structure of the
cosmos, the origin and development of animals and man, and the nature of
matter itself. Nowadays, so enormously involved has become the mass of
mere facts regarding eac