Way of the Lawless by Max Brand

He had never studied any men as he was watching these men at cards. Andrew Lanning had spent most of his life quite indifferent to the people around him, but now it was necessary to make quick and sure judgments. He had to read unreadable faces. He had to guess motives. He had to sense the coming of danger before it showed its face. And, watching them with close intentness, he understood that at least three of them were cheating at every opportunity. Henry, alone, was playing a square game; as for the heavy winner, Larry, Andrew had reason to believe that he was adroitly palming an ace now and then -- luck ran too consistently his way. For his own part, he was no card expert, and he smiled as Henry made his offer.

"I've got eleven dollars and fifty cents in my pocket," Andrew said frankly. "I won't sit in at that game."