tion, which assigns to bodies degrees of heaviness and
lightness proportioned to the mass and distance of the bodies which
attract them, never occurred to him. Yet the affinities of similar
substances have some effect upon the composition of the world, and
of this Plato may be thought to have had an anticipation. He may be
described as confusing the attraction of gravitation with the attraction
of cohesion. The influence of such affinities and the chemical action of
one body upon another in long periods of time have become a recognized
principle of geology.

(2) Plato is perfectly aware--and he could hardly be ignorant--that
blood is a fluid in constant motion. He also knew that blood is partly a
solid substance consisting of several elements, which, as he might have
observed in the use of 'cupping-glasses', decompose and die, when no
longer in motion. But the specific discovery that the blood flows out on
one side of the heart through the arteries and returns through the veins
on the other, which is commonly called the circulation of the blood, was
absolutely unknown to him.

A further study of the Timaeus suggests some after-thoughts which may be
conveniently brought together in this place. The topics which I propose
briefly to reconsider are (a) the relation of the Timaeus to the other
dialogues of Plato and to the previous philosophy; (b) the nature of God
and of creation (c) the morality of the Timaeus:--

(a) The Timaeus is more imaginative and less scientific than any other
of the Platonic dialogues. It is conjectural astronomy, conjectural
natural philosophy, conjectural medicine. The writer himself is
constantly repeating that he is speaking what is probable only. The
dialogue is put into the mouth of Timaeus, a Pythagorean philosopher,
and therefore here, as in the Parmenides, we are in doubt how far Plato
is expressing his own sentiments. Hence the connexion with the other
dialogues is comparatively slight. We may fill up the lacunae of the
Timaeus by the help of the Republic or Phaedrus: we may identify the
same and other with the (Greek) of the Philebus. We may find in the Laws
or in the Statesman parallels with the account of creation and of the
first origin of man. It would be possible to frame a scheme in which all
these various elements might have a place. But such a mode of proceeding
would be unsatisfactory, because we have no reason to suppose that Plato
intended his scattered thoughts to be collec