All those parts

that do not subdivide into parts uniform with
themselves are composed of parts that do so subdivide, for instance,
hand is composed of flesh, sinews, and bones. Of animals, some
resemble one another in all their parts, while others have parts
wherein they differ. Sometimes the parts are identical in form or
species, as, for instance, one man's nose or eye resembles another
man's nose or eye, flesh flesh, and bone bone; and in like manner with
a horse, and with all other animals which we reckon to be of one and
the same species: for as the whole is to the whole, so each to each
are the parts severally.