Metaphysicians have carried the distinction further: apples, they say, may have not only the same outward shape, but the same inward constitution, which, therefore, may be called the Form of apple-stuff itself--namely, a certain pulpiness, juiciness, sweetness, etc.; qualities common to all dessert apples: yet their Matter is different, one being here, another there--differing in place or time, if in nothing else.

The definition of a species is the form of every specimen of it.
To apply this distinction to the things of Logic: it is easy to see how two propositions may have the same Form but different Matter: not using 'Form' in the sense of 'shape,' but for that which is common to many things, in contrast with that which is peculiar to each.

Thus, _All male lions are tawny_ and _All water is liquid at 50 deg.

Fahrenheit_, are two propositions that have the same form, though their matter is entirely different.

They both predicate something of the whole of their subjects, though their subjects are different, and so are the things predicated of them.