But we shall have to explain more clearly the sense in which the word
"parts" must here be taken. To begin with, there is here no question of
parts of a body, whether homogeneous or heterogeneous. We shall make
but a single observation, namely, that when treating of homogeneous
bodies, parts refer to mass, and not to form. For instance, take
whiteness. The whiteness of one part of the milk, is not a part of the
whiteness of all the milk in existence; it is the whiteness of a part,
and not the part of whiteness; for, taken in general, whiteness has
neither size nor quantity. Only with these restrictions can we say that
there are parts in the forms suitable to corporeal things.