equator, at the rate of twelve miles a day, and yet no man
among them would have known that he was travelling two miles a day
backward unless he had lifted his eyes from the track in which he was
plodding. It is not only going backward that the plain practical workman
is liable to, if he will not look up and look around; he may go forward
to ends he little dreams of. It is a simple business for a mason to
build up a niche in a wall; but what if, a hundred years afterwards when
the wall is torn down, the skeleton of a murdered man drop out of the
niche? It was a plain practical piece of carpentry for a Jewish artisan
to fit two pieces of timber together according to the legal pattern in
the time of Pontius Pilate; he asked no questions, perhaps, but we know
what burden the cross bore on the morrow! And so, with subtler tools
than trowels or axes, the statesman who works in policy without
principle, the theologian who works in forms without a soul, the
physician who, calling himself a practical man, refuses to recognize the
larger laws which govern his changing practice, may all find that they
have been building truth into the wall, and hanging humanity upon the
cross.

The truth is, that medicine, professedly founded on observation, is as
sensitive to outside influences, political, religious, philosophical,
imaginative, as is the barometer to the changes of atmospheric density.
Theoretically it ought to go on its own straightforward inductive path,
without regard to changes of government or to fluctuations of public
opinion. But look a moment while I clash a few facts together, and see
if some sparks do not reveal by their light a closer relation between the
Medical Sciences and the conditions of Society and the general thought of
the time, than would at first be suspected.

Observe the coincidences between certain great political and intellectual
periods and the appearance of illustrious medical reformers and teachers.
It was in the age of Pericles, of Socrates, of Plato, of Phidias, that
Hippocrates gave to medical knowledge the form which it retained for
twenty centuries. With the world-conquering Alexander, the
world-embracing Aristotle, appropriating anatomy and physiology, among
his manifold spoils of study, marched abreast of his royal pupil to wider
conquests. Under the same Ptolemies who founded the Alexandrian Library
and Museum, and ordered the Septuagint version of the Hebrew Scriptures,
the infallible Herop