der the patronage of the enlightened ruler.
These earliest of really scientific investigators of the mechanism
of the human body were named Herophilus and Erasistratus. These two
anatomists gained their knowledge by the dissection of human bodies
(theirs are the first records that we have of such practices), and
King Ptolemy himself is said to have been present at some of these
dissections. They were the first to discover that the nerve-trunks have
their origin in the brain and spinal cord, and they are credited
also with the discovery that these nerve-trunks are of two different
kinds--one to convey motor, and the other sensory impulses. They
discovered, described, and named the coverings of the brain. The name of
Herophilus is still applied by anatomists, in honor of the discoverer,
to one of the sinuses or large canals that convey the venous blood
from the head. Herophilus also noticed and described four cavities or
ventricles in the brain, and reached the conclusion that one of these
ventricles was the seat of the soul--a belief shared until comparatively
recent times by many physiologists. He made also a careful and fairly
accurate study of the anatomy of the eye, a greatly improved the old
operation for cataract.

With the increased knowledge of anatomy came also corresponding advances
in surgery, and many experimental operations are said to have been
performed upon condemned criminals who were handed over to the surgeons
by the Ptolemies. While many modern writers have attempted to discredit
these assertions, it is not improbable that such operations were
performed. In an age when human life was held so cheap, and among a
people accustomed to torturing condemned prisoners for comparatively
slight offences, it is not unlikely that the surgeons were allowed
to inflict perhaps less painful tortures in the cause of science.
Furthermore, we know that condemned criminals were sometimes handed over
to the medical profession to be "operated upon and killed in whatever
way they thought best" even as late as the sixteenth century.
Tertullian(1) probably exaggerates, however, when he puts the number of
such victims in Alexandria at six hundred.

Had Herophilus and Erasistratus been as happy in their deductions as to
the functions of the organs as they were in their knowledge of anatomy,
the science of medicine would have been placed upon a very high plane
even in their time. Unfortunately, however, they not only drew erron