I am able to sketch the physical and intellectual life of a cocainist who, like many others, came to me in his misery for help. On account of a facial neuralgia he had frequently taken morphia until a dentist plugged cotton-wool soaked in a 15 per cent solution of cocaine into several carious teeth. From that time onward the need for morphia disappeared. Carious teeth served as receptacles for the cocaine tampons, i.e. places from which the cocaine passed into the blood, and that in abundance. At certain times he pressed these cocaine plugs between the teeth. The greater part of the cocaine passed into the stomach with the saliva. This particular method of application had not existed hitherto but likewise had fatal results. It was introduced in ever-increasing quantities-finally over 1 gr. daily. The unfortunate man's own words were as follows: "With regard to the action of cocaine on my personality, I can honestly declare that the past five years can be counted among the happiest of my life, and I owe this primarily to cocaine. Nothing can refute this plain fact." His letter of twelve pages terminates with these words: "Time is necessary to bring my conception of the world to a point which is founded on the sentence: God is a substance!" The latter phrase impressively shows in an undisguised fashion the whole effect which cocaine exerts on the brain. The individual is so attached to his periods of delight that everything else, even the future, is despised, although the evils which the approaching catastrophe is absolutely certain to bring with it slowly become apparent even to him.
Louis Lewin, M.D., Phantastica. A classic survey on the use and abuse of mind-altering plants. Parrk Street Press, 1998. p.69.