On Generation and corruption
flesh and converts it into actual flesh. The acceding food, therefore,
must be together with the growing thing: for if it were apart from it,
the change would be a coming-to-be. For it is possible to produce fire
by piling logs on to the already burning fire. That is 'growth'. But
when the logs themselves are set on fire, that is 'coming-to-be'.
'Quantum-in-general' does not come-to-be any more than 'animal'
which is neither man nor any other of the specific forms of animal:
what 'animal-in-general' is in coming-to-be, that 'quantum-in-general'
is in growth. But what does come-to-be in growth is flesh or bone-or a
hand or arm (i.e. the tissues of these organic parts). Such things
come-to-be, then, by the accession not of quantified-flesh but of a
quantified-something. In so far as this acceding food is potentially
the double result e.g. is potentially so-much-flesh-it produces
growth: for it is bound to become actually both so-much and flesh. But
in so far as it is potentially flesh only, it nourishes: for it is
thus that 'nutrition' and 'growth' differ by their definition. That is
why a body's' nutrition' continues so long as it is kept alive (even
when it is diminishing), though not its 'growth'; and why nutrition,
though 'the same' as growth, is yet different from it in its actual
being. For in so far as that which accedes is potentially 'so
much-flesh' it tends to increase flesh: whereas, in so far as it is
potentially 'flesh' only, it is nourishment.
The form of which we have spoken is a kind of power immersed in
matter-a duct, as it were. If, then, a matter accedes-a matter,
which is potentially a duct and also potentially possesses determinate
quantity the ducts to which it accedes will become bigger. But if it
is no longer able to act-if it has been weakened by the continued
influx of matter, just as water, continually mixed in greater and
greater quantity with wine, in the end makes the wine watery and
converts it into water-then it will cause a diminution of the quantum;
though still the form persists.