Lactucarium is a reddish brown substance with a narcotic odour and bitter taste, having a considerable resemblance to opium. On analysis it yields a snow white crystalline substance called _lactucin_, which is narcotic in its effects. Dr. Duncan recommended the use of lactucarium as a substitute for opium, the anodyne properties of which it possesses, without being followed with the same injurious effects. In France, a water is distilled from lettuce, and used as a mild sedative. Experiments of the effects of lettuce-opium upon animals are detailed by Orfila, who states that three drachms introduced into the stomach of a dog killed it in two days, without causing any remarkable symptoms; two drachms applied to a wound in the back induced giddiness, slight sopor, and death in three days; and thirty-six grains injected, in a state of solution, into the jugular vein caused dulness, weakness, slight convulsions, and death in 18 minutes. In North America the prickly lettuce is more common than with us, and from it the American lactucarium is extracted. In Guinea a species of lettuce is found wild, possessing precisely similar properties, and applicable to a like use. This plant is largely used by the negroes as a salad and also as an opiate. The plants cultivated for the sake of the juice are grown in a rich soil, with a southern aspect. In such a situation they thrive vigorously, and send up thick, juicy, flower stems. As soon as these have attained a considerable height, and before the flowers expand, a portion of the top is cut off. The milky juice quickly exudes from the wound, while the heat of the sun renders it so viscid that, instead of flowing down, it concretes on the stem in a brownish flake. After it has acquired a proper consistence it is removed. As the juice closes up the vessels of the plant, another slice is taken off lower down the stem, and the juice again flows freely and another flake is formed. The same process is repeated as long as the plant affords any juice. To the crude juice, thus obtained, the name of lactucarium has been given. “This,” says Johnston, “is one of those narcotics in which many of us unconsciously indulge. The eater of green lettuce as a salad, takes a portion of it in the juice of the leaves he swallows; and many of my readers, after this is pointed out to them, will discover that their heads are not unaffected after indulging copiously in a lettuce salad. Eaten at night, the lettuce causes sleep; eaten during the day, it soothes and calms and allays the tendency to nervous irritability. And yet the lover of lettuce would take it very much amiss if he were told that he ate his green leaves, partly at least, for the same reason as the Turk or the Chinaman takes his whiff from the tiny opium pipe: that, in short, he was little better than an opium-eater, and his purveyor than the opium smuggler on the coast of China.”