"No--you don't even 'burn.' I don't think, you know, you'll guess it." "How then can I judge how vulgar it is ?" "You'll judge when I do tell you"-- and he persuaded her to patience.
But it may even now frankly be mentioned that he in the sequel never WAS to tell her.

He actually never did so, and it moreover oddly occurred that by the law, within her, of the incalculable, her desire for the information dropped and her attitude to the question converted itself into a positive cultivation of ignorance.

In ignorance she could humour her fancy, and that proved a useful freedom.

She could treat the little nameless object as indeed unnameable--she could make their abstention enormously definite.

There might indeed have been for Strether the portent of this in what she next said.
"Is it perhaps then because it's so bad--because your industry as you call it, IS so vulgar--that Mr.Chad won't come back?
Does he feel the taint?
Is he staying away not to be mixed up in it ?" "Oh," Strether laughed, "it wouldn't appear--would it ?--that he feels 'taints'! He's glad enough of the money from it, and the money's his whole basis.