Nor would you say that medicine is the art of receiving pay because a man takes fees when he is engaged in healing?

Certainly not.

And we have admitted, I said, that the good of each art is specially confined to the art?

Yes.

Then, if there be any good which all artists have in common, that is to be attributed to something of which they all have the common use?

True, he replied.

And when the artist is benefited by receiving pay the advantage is gained by an additional use of the art of pay, which is not the art professed by him?

He gave a reluctant assent to this.