From Letters of Note, here's a letter the novelist John D. Swain wrote to his son in 1908 as the boy began college at Yale:

You will probably play cards in college; most men do,—I did. The gambling instinct in man is primordial. Kept under due bounds, if not useful, it is at least comparatively harmless. This is the very best that I or any honest man can say of it. I should be glad if you never cared to gamble; but l do not ask it. Assuming that you will, l do not insult you, and myself equally, by warning you against unfairness; to suppose you capable of cheating at cards is to suppose an impossibility. You could not do so without forfeiting the right ever to enter your home again. But some careless and insidious practices, not unknown in my day and class, savor to the upright mind of cheating, without always incurring its penalties.

To play with men whom you know cannot afford to lose, and who must either cheat or suffer privation; to play when you yourself must win your bet to square yourself; that is, when you do not reasonably see how you are going to raise the money to pay providing you lose,—this is a gambler's chance to which no gentleman will ever expose his fellow players.

There is nothing heroic about these desperate casts of the die; one risks only the other fellow's money. These practices I ask and expect you to avoid.