Sex was to be treated as no other impulse in our nature has ever been treated by civilized people. All the others, we admit, have to be bribed. Absolute obedience to your instinct for self-preservation is what we call cowardice; to your acquisitive impulse, avarice. Even sleep must be resisted if you're a sentry. But every unkindness and breach of faith seems to be condoned provided that the object aimed at is "four bare legs in a bed".