The craving for a drink in real dipsomaniacs, or for opium or chloral in those subjugated, is of a strength of which normal persons can form no conception. ‘Were a keg of rum in one corner of a room and were a cannon constantly discharging balls between me and it, I could not refrain from passing before that cannon in order to get the rum’; ‘If a bottle of brandy stood at one hand and the pit of hell yawned at the other, and I were convinced that I should be pushed in as sure as I took one glass, I could not refrain’: such statements abound in dipsomaniacs’ mouths.

William James, Principles of Psychology (New York: Henry Holt and Company, 1890), p. 543. Via Laurence. Thanks Laurence!