corn. For things of this kind are, to a greater or less degree, of
earth. For of all these bodies some admit of softening by heat, the
rest give off fumes and are formed by refrigeration. So again in
natron, salt, and those kinds of stones that are not formed by
refrigeration and cannot be melted. Blood, on the other hand, and
semen, are made up of earth and water and air. If the blood contains
fibres, earth preponderates in it: consequently its solidifies by
refrigeration and is melted by liquids; if not, it is of water and
therefore does not solidify. Semen solidifies by refrigeration, its
moisture leaving it together with its heat.
We must investigate in the light of the results we have arrived at
what solid or liquid bodies are hot and what cold.
Bodies consisting of water are commonly cold, unless (like lye,
urine, wine) they contain foreign heat. Bodies consisting of earth, on
the other hand, are commonly hot because heat was active in forming
them: for instance lime and ashes.
We must recognize that cold is in a sense the matter of bodies.
For the dry and the moist are matter (being passive) and earth and
water are the elements that primarily embody them, and they are
characterized by cold. Consequently cold must predominate in every
body that consists of one or other of the elements simply, unless such
a body contains foreign heat as water does when it boils or when it
has been strained through ashes. This latter, too, has acquired heat
from the ashes, for everything that has been burnt contains more or
less heat. This explains the generation of animals in putrefying
bodies: the putrefying body contains the heat which destroyed its
Bodies made up of earth and water are hot, for most of them derive
their existence from concoction and heat, though some, like the