e Nature as all-sufficient for healing, and physicians as
only her servants. He discussed medical subjects freely and without an
air of mystery, scorning all pretence, and he was also courageous enough
to acknowledge his limitations and his failures. When the times in which
he lived are considered, it is difficult to know which of his qualities
to admire most, his love of knowledge, his powers of observation, his
logical faculty, or his courage and truthfulness.

The central principle of belief of Hippocrates and the Dogmatists was
that health depended on the proper proportion and action in the body of
the four elements, earth, water, air, and fire, and the four cardinal
humours, blood, phlegm, yellow bile and black bile. The due combination
of these was known as _crasis_, and existed in health. If a disease were
progressing favourably these humours became changed and combined
(coction), preparatory to the expulsion of the morbid matter (crisis),
which took place at definite periods known as critical days. Hippocrates
also held the theory of fluxions, which were conditions in the nature of
congestion, as it would now be understood.

In his time public opinion condemned dissection of the human body, but
it is certain that dissections were performed by Hippocrates to a
limited extent. He did not know the difference between the arteries and
the veins, and nerves and ligaments and various membranes were all
thought to have analogous functions, but his writings display a correct
knowledge of the anatomy of certain parts of the body such as the joints
and the brain. This defective knowledge of anatomy gave rise to fanciful
views on physiology, which, among much that is admirable, disfigure the
Hippocratic writings.

The belief that almost all medical and surgical knowledge is modern,
though flattering to our self-complacency, is disturbed by the study of
the state of knowledge in the time of Hippocrates. To him we are
indebted for the classification of diseases into sporadic, epidemic,
and endemic, and he also separated acute from chronic diseases. He
divided the causes of disease into two classes: general, such as
climate, water and sanitation; and personal, such as improper food and
neglect of exercise.

He based his conclusions on the observation of appearances, and in this
way began a new era. He was so perfect in the observation of external
signs of disease that he has never in this respect been excelled. The
state o