I say "the equivalent of 18 grains of morphia," because although the majorify of _habitués_ use that principle of opium as their favorite form, there are some who after many years' use of the drug still adhere to crude gum opium or laudanum. The portability and ease of exhibition which belong to morphia--the fact that it fails to sicken some persons in whom any other opiate produces violent nausea--its usual certainty, rapidity, and uniformity of action, and the ability which it possesses to produce the characteristic effects of the narcotic after other preparations have become comparatively inert, make it the most general form in use among opium-eaters of long standing. Still, bearing in mind the wonderful complexity of opium (_vide_ "What Shall They Do to be Saved?") and the equally marvellous diversity in the manner in which it affects different people, we can not wonder at the fact that some of its victims require for their desired effect either the crude drug or other preparations containing its principles entire. Morphia is by far the most important of these principles, and more nearly than any one stands typical of them all. Still, it is easy to conceive how certain constitutions may respond more sympathetically to the complex agent of Nature's compounding than to any one of its constituents. [Footnote: In some cases, especially of shorter standing, codeia may be used as the form of opiate to diminish on. In any case its employment is worth trying, for it possesses much of the pain-controlling efficiency of opium and morphia, with less of their congestive action upon the brain. Practically it may be treated in such an experiment as the equivalent of opium; not that it at all represents all the drug's operations, but that where crude opium has been the form in use, codeia may be substituted grain for grain. Some patiets find it quite valueless as a substitute, but there is always a chance of its proving adequate. When tried, the best form is a solution similar to Magendie's, but replacing one grain of morphia by six of codeia.] We may therefore find it necessary to carry on our reformatory process upan laudanum or M'Munn's Elixir, but by far the larger number of cases will do better by being put instantly upon a regimen of Magendie's Solution of Morphia. The formula for this preparation is: Rx Morph. Sulph. . . . . . . . . . . . grs. xvi. Aqua Destill. . . . . . . . . . . . ounce j Elix. Vitrioli. . . . . . . . . . . quant. suff. Mr. Edgerton has used 18 grains of morphia per diem. His equivalent in Magendie's Solution will be 9 fluid drachms.