identical with that viewed in the preceding one. But now as
regards subject matter we pass on to those diverse phases of the
physical world which are the field of the chemist, and to those
yet more intricate processes which have to do with living
organisms. So radical are the changes here that we seem to be
entering new worlds; and yet, here as before, there are
intimations of the new discoveries away back in the Greek days.
The solution of the problem of respiration will remind us that
Anaxagoras half guessed the secret; and in those diversified
studies which tell us of the Daltonian atom in its wonderful
transmutations, we shall be reminded again of the Clazomenian
philosopher and his successor Democritus.

Yet we should press the analogy much too far were we to intimate
that the Greek of the elder day or any thinker of a more recent
period had penetrated, even in the vaguest way, all of the
mysteries that the nineteenth century has revealed in the fields
of chemistry and biology. At the very most the insight of those
great Greeks and of the wonderful seventeenth-century
philosophers who so often seemed on the verge of our later
discoveries did no more than vaguely anticipate their successors
of this later century. To gain an accurate, really specific
knowledge of the properties of elementary bodies was reserved for
the chemists of a recent epoch. The vague Greek questionings as
to organic evolution were world-wide from the precise inductions
of a Darwin. If the mediaeval Arabian endeavored to dull the
knife of the surgeon with the use of drugs, his results hardly
merit to be termed even an anticipation of modern anaesthesia.
And when we speak of preventive medicine--of bacteriology in all
its phases--we have to do with a marvellous field of which no