What is the seat of a movement acting on an object by passing from
internal power to actualization? Is it in the motor? How will that
which is moved and which suffers be able to receive it? Is it in the
movable element? Why does it not remain in the mover? Movement must
therefore be considered as inseparable from the mover, although not
exclusively; it must pass from the mover into the mobile (element)
without ceasing to be connected with the mover, and it must pass
from the mover to the moved like a breath (or influx).[426] When the
motive power produces locomotion, it gives us an impulse and makes
us change place ceaselessly; when it is calorific, it heats; when,
meeting matter, it imparts thereto its natural organization, and
produces increase; when it removes something from an object, this
object decreases because it is capable thereof; last, when it is the
generative power which enters into action, generation occurs; but if
this generative power be weaker than the destructive power, there
occurs destruction, not of what is already produced, but of what was
in the process of production. Likewise, convalescence takes place as
soon as the force capable of producing health acts and dominates; and
sickness occurs, when the opposite power produces a contrary effect.
Consequently, movement must be studied not only in the things in
which it is produced, but also in those that produce it or transmit
it. The property of movement consists therefore in being a movement
endowed with some particular quality, or being something definite in a
particular thing.