Opium

"Opium creates a psychic screen between the mind and the body of the smoker, so that pain becomes an abstraction, without the sharpness of physical sensation...The anesthesia produced by opium may be described as a sort of cerebral intoxication, a psychic fog between oneself and external reality that diminishes the outer world. The smoker forgets he has a body. His mind escapes the prison of the flesh and the material world, and is removed to the periphery of reality by the centrifugal force of opium. He escapes not only his own body, but also the physical world in which his body exists. Opium plays a siren's tune on the piano off his nerves, and as he listens, the smoker forgets about the passage of time, and he also forgets about hunger, thirst, fatigue and sleep."
Nguyen Te Duc  (Le Livre de l'opium)