Opium resembles the other agents of intoxication in this, that the fondness for it increases with use, and that at last, it becomes nearly essential for bodily comfort and peace of mind. The quantity which may be taken varies exceedingly, and depends wholly upon age, constitution, and habit. A single drop of laudanum has been known to kill a newborn child; and four grains of solid opium have destroyed an adult. Certain diseases, such as fevers, phrensies, &c., facilitate the action of opium upon the system; others, such as diarrhœa, cramp, &c., resist it; and a quantity which would destroy life in the former, would have little perceptible effect in the latter. By habit, enormous quantities of the drug may be taken with comparative impunity. There are many persons in this country who make a practice of swallowing half an ounce of laudanum night and morning, and some will even take from one to two drachms daily of solid opium. The Teriakis, or opium-eaters of Constantinople, will sometimes swallow a hundred grains at a single dose. Nay, it is confidently affirmed that some of them will take at once three drachms in the morning, and repeat the same dose at night, with no other effect than a pleasing exhilaration of spirits. The “English Opium-Eater” himself furnishes one of the most extraordinary instances on record of the power of habit in bringing the body to withstand this drug. He took daily _eight thousand drops_ of laudanum, containing _three hundred and twenty grains_ of opium. This enormous quantity he reduced suddenly, and without any considerable effort, to _one thousand drops_, or _forty grains_. “Instantaneously,” says he, “and as if by magic, the cloud of profoundest melancholy which rested upon my brain, like some black vapours which I have seen roll away from the summits of the mountains, drew off in one day—passed off with its murky banners, as simultaneously as a ship that has been stranded, and is floated off by the spring-tide.” The circumstance of the body being brought by degrees to withstand a great quantity of opium is not solitary, but exists as a general rule with regard to all stimulants and narcotics. A person who is in the habit of drinking ale, wine, or spirits, will take much more with impunity than one who is not; and the faculty of withstanding these agents goes on strengthening till it acquires a certain point, after which it becomes weakened. When this takes place, there is either organic disease or general debility. A confirmed drunkard, whose constitution has suffered from indulgence, cannot take so much liquor, without feeling it, as one who is in the habit of taking his glass, but whose strength is yet unimpaired. It is, I suspect, the same, though probably in a less degree, with regard to opium.