But since they had been together she had given him glimpses of
her past that made him angrily long to shelter and defend her
future. It was intolerable that a spirit as fine as hers should
be ever so little dulled or diminished by the kind of
compromises out of which their wretched lives were made. For
himself, he didn't care a hang: he had composed for his own
guidance a rough-and-ready code, a short set of "mays" and
"mustn'ts" which immensely simplified his course. There were
things a fellow put up with for the sake of certain definite and
otherwise unattainable advantages; there were other things he
wouldn't traffic with at any price. But for a woman, he began
to see, it might be different. The temptations might be
greater, the cost considerably higher, the dividing line between
the "mays" and "mustn'ts" more fluctuating and less sharply
drawn. Susy, thrown on the world at seventeen, with only a weak
wastrel of a father to define that treacherous line for her, and
with every circumstance soliciting her to overstep it, seemed to
have been preserved chiefly by an innate scorn of most of the
objects of human folly. "Such trash as he went to pieces for,"
was her curt comment on her parent's premature demise: as
though she accepted in advance the necessity of ruining one's
self for something, but was resolved to discriminate firmly
between what was worth it and what wasn't.

This philosophy had at first enchanted Lansing; but now it began
to rouse vague fears. The fine armour of her fastidiousness had
preserved her from the kind of risks she had hitherto been
exposed to; but what if others, more subtle, found a joint in
it? Was there, among her delicate discriminations, any
equivalent to his own rules? Might not her taste for the best