The Timaeus of Plato

89 B] TIMAIOS. 333
within by the particles that enter, and again
is dried and
moistened by those that are outside, and by the agency of these
two forces suffers all that ensues upon these conditions, if we
submit the body passively to the forces aforesaid, it is overcome
and destroyed
: but if we imitate what we have called the fostress
and nurse of the All, and allow the body, if possible, never to be
inactive, but keep it astir and, exciting continual vibrations in it,
furnish it with the natural defence against the motions from
without and within ; and by moderately exercising it bring into
orderly relation with each other according to their affinities
the affections and particles that are going astray in the body ;
then, as we have already described in speaking of the universe,
we shall not suffer mutually hostile particles to be side by side
and to engender discord and disease in the body, but we shall
set friend beside friend so as to bring about a healthy state.
Of all motions that which arises in any body by its own action
is the best (for it is most nearly allied to the motion of thought
and of the All), but that which is
brought about by other
agency is inferior and the worst of all is that
;
which, while the
body is lying still, is
produced by other agents which move
it
piecemeal. Accordingly of all modes of purifying and
restoring the body gymnastic is the best the next best is
;
any swinging motion such as of sailing or any other conveyance
of the body which does not tire it: a third kind is
useful sometimes under absolute necessity, but in no other circumstances
should be employed by a judicious person, I mean
medical purgation effected by drugs. No disease, not involving
imminent danger, should be irritated by drugs. For
in which the body may be exercised are irdvruv, 8