Soul, indeed, is a certain medium between an impartible essence, and an essence which is divisible about bodies. But intellect is an impartible essence alone. And qualities and material forms are divisible about bodies.
Not everything which acts on another, effects that which it does effect by approximation and contact; but those natures which effect any thing by approximation and contact, use approximation accidentally.

5 - 6 - Auxiliaries to the Perception of Intelligible Natures