It's wisdom that's cheap, and it's fortune that's dear.

That ain't in Poor Richard; but it ought to be," concluded Israel, suddenly slamming down the pamphlet.
He walked across the room, looked at the artificial flowers, and the rose-colored soap, and again went to the table and took up the two books.
"So here is the 'Way to Wealth,' and here is the 'Guide to Paris.' Wonder now whether Paris lies on the Way to Wealth?
if so, I am on the road.

More likely though, it's a parting-of-the-ways.

I shouldn't be surprised if the Doctor meant something sly by putting these two books in my hand.

Somehow, the old gentleman has an amazing sly look--a sort of wild slyness--about him, seems to me.