An empty phial of morphia

Our narrator hoped to win back Gilberte's affection by feigning indifference to her. The plan backfires, and our hero's remorse is likened to the pangs of an addict's withdrawal.

"New Year's Day went by, hour after hour, without bringing me that letter from Gilberte...On the days that followed I wept a great deal. True, this was due to the fact that, having been less sincere than I thought in my renunciation of Gilberte, I had clung to the hope of a letter from her in the New Year. And seeing that hope exhausted before I had time to shelter myself behind another, I suffered like an invalid who has emptied his phial of morphia without having another within his reach."