rection
of the blood that entered and left the organ, but he did not appreciate
that it was a pump for distributing the blood, regarding it rather as
a fireplace from which the innate heat of the body was derived. He knew
that the pulsatile force was resident in the walls of the heart and in
the arteries, and he knew that the expansion, or diastole, drew blood
into its cavities, and that the systole forced blood out. Apparently his
view was that there was a sort of ebb and flow in both systems--and yet,
he uses language just such as we would, speaking of the venous system
as ". . . a conduit full of blood with a multitude of canals large and
small running out from it and distributing blood to all parts of the
body." He compares the mode of nutrition to irrigating canals and
gardens, with a wonderful dispensation by nature that they should
"neither lack a sufficient quantity of blood for absorption nor
be overloaded at any time with excessive supply." The function of
respiration was the introduction of the pneuma, the spirits which passed
from the lungs to the heart through the pulmonary vessels. Galen went a
good deal beyond the idea of Aristotle, reaching our modern conception
that the function is to maintain the animal heat, and that the
smoky matters derived from combustion of the blood are discharged by
expiration.

I have dwelt on these points in Galen's physiology, as they are
fundamental in the history of the circulation; and they are sufficient
to illustrate his position. Among his other brilliant experiments were
the demonstration of the function of the laryngeal nerves, of the
motor and sensory functions of the spinal nerve roots, of the effect
of transverse incision of the spinal cord, and of the effect of
hemisection. Altogether there is no ancient physician in whose writings
are contained so many indications of modern methods of research.

Galen's views of disease in general are those of Hippocrates, but
he introduces many refinements and subdivisions according to the
predominance of the four humors, the harmonious combination of
which means health, or eucrasia, while their perversion or improper
combination leads to dyscrasia, or ill health. In treatment he had not
the simplicity of Hippocrates: he had great faith in drugs and collected
plants from all parts of the known world, for the sale of which he
is said to have had a shop in the neighborhood of the Forum. As I
mentioned, he was an eclectic, held h