corresponding to the head, heart and belly. The human soul differs from
the soul of the world in this respect, that it is enveloped and finds its
expression in matter, whereas the soul of the world is not only enveloped
or diffused in matter, but is the element in which matter moves. The
breath of man is within him, but the air or aether of heaven is the element
which surrounds him and all things.

Pleasure and pain are attributed in the Timaeus to the suddenness of our
sensations--the first being a sudden restoration, the second a sudden
violation, of nature (Phileb.). The sensations become conscious to us when
they are exceptional. Sight is not attended either by pleasure or pain,
but hunger and the appeasing of hunger are pleasant and painful because
they are extraordinary.

Section 6.

I shall not attempt to connect the physiological speculations of Plato
either with ancient or modern medicine. What light I can throw upon them
will be derived from the comparison of them with his general system.

There is no principle so apparent in the physics of the Timaeus, or in
ancient physics generally, as that of continuity. The world is conceived
of as a whole, and the elements are formed into and out of one another; the
varieties of substances and processes are hardly known or noticed. And in
a similar manner the human body is conceived of as a whole, and the
different substances of which, to a superficial observer, it appears to be
composed--the blood, flesh, sinews--like the elements out of which they are
formed, are supposed to pass into one another in regular order, while the
infinite complexity of the human frame remains unobserved. And diseases
arise from the opposite process--when the natural proportions of the four