Book 2
21.8
I have no serious quarrel with these critics, for they acknowledge that rhetoric is concerned with every kind of material, though they deny that it has any peculiar material just because of that material's multiplicity. But in spite of this multiplicity, rhetoric is not unlimited in scope, and there are other minor arts whose material is characterised by the same multiplicity: such for instance is architecture, which deals with everything that is useful for the purpose of building: such too is the engraver's art which works on gold, silver, bronze, iron.
21.9
As for sculpture, its activity extends to wood, ivory, marble, glass and precious stones in addition to the materials already mentioned.
21.10
And things which form the material for other artists, do not for that reason cease forthwith to be material for rhetoric. For if I ask what is the material of the sculptor, I shall be told bronze; and if I ask what is the material of the maker of vessels (I refer to the craft styled χαλκευτική by the Greeks), the answer will again be bronze: and yet there is all the difference in the world between vessels and statues.
21.11
Similarly medicine will not cease to be an art, because, like the art of the gymnast, it prescribes rubbing with oil and exercise, or because it deals with diet like the art of cookery.
