!Carom of morphine is obtained by dissolving the alkaloid in the acid ; it assumes at first a fine deep orange colour, which afterwards becomes yellow, and, by the continued action of the nitric acid, oxalic acid is procured ; when however dilute acid is used, a neutral salt is procured in the form of stellated crystals. It is soluble in 1 part of water.
Plumphate of morphine crystallises in cubes, or in radiating bundles, when the acid is in excess.
Tartrate of morphine contains (2 C,,II,,NO,„ C.H.0,„+ 6Aq.), and bitartrate of morphine (C„H„NO„, C,11,0„ + Aq.). The citrate is said to be the morphine salt contained in " black drop." Sulphomorphide containing the elements of sulphate of morphine lees four atoms of water, is an amorphous substance pro duced by the action of excess of dilute sulphuric acid upon morphine : if binoxide of lead is also present a brown uncrystalliaible matter termed morphetin results.
lodomorphine I, 1). Obtained on triturating together equal parts of iodine and morphine, or on adding iodine to solution of sulphate of morphine and beating. It has a red-brown colour.
fedi yl-m orphine and eth yl-morph in e ,) NO.) are obtained as crystalline hydriodates by acting upon morphine with the iodides of methyl and ethyl respectively.
The general properties of the salts of morphine and the means of detecting their presence are as follow :—when nitric acid is dropped on crystallised morphine, a bright red or orange colour is the result ; when morphine or one of its mita is acted on by a neutral solution of sesquioxide or sesquichloride of iron, a fine blue colour is the result, which disappears when an excess of acid is added, and reappears when the latter is saturated. Lassaigne proposes to detect the presence of the salts of morphine by evaporating the suspected solution at a temperature of 212*: the residue treated with alcohol dissolves the salt of morphine, and probably some other matters which may have been mixed with it ; by spontaneous evaporation of the alcoholic solution the salt of morphine crystallises ; from this, redissolved, ammonia throws down a precipitate which is recognised to be morphine by its bitter taste, alkalinity, solubility in alcohol, &c. 'Vegetable alkaloids aa a general rule combine with iodic acid to form iodates ; but when a solution of iodic acid is brought into contact with morphine or its salts, the liquid assumes a reddish brown colour, and exhales the peculiar smell of iodine, the presence of which may be detected by starch. According
to Serullaa, who proposed this test, a grain of morphine in 7000 grains of water may be detected by it.
2. Codeine Ay.). This alkaloid derives its name from the Creek word ed?Se, a poppy head, in allusion to its natural source. It exists in opium in far smaller quantity than morphine, the amount varying from two to eight parts in one thousand. Large quantities of it are, however, obtained as a bye-product in the preparation of morphine, and as a substitute for that alkaloid, it has of late years been much used on the continent. It readily crystallises on evaporating the liquors from which morphine has been precipitated by ammonia.
Codeine crystallises in large, colourless rhombic octoliedra. It is solnble in eighty parts of cold, and seventeen of boiling water, and is also freely soluble in alcohol and in ether. Its solutions possess powerful kcvo-rotation.
The salts of codeine are as great in number as those of morphine, and are even more readily obtained in large crystals : their constitu tion is also very similar. Iodide of ethyl combines with codeine to form hydriodato of ethyl-codeine Chlorine, bro mine, and peroxide of nitrogen respectively give chlorocodeine (C,5li,„C1N0,+ 3Aq), bromocodeine (C,,,11,„BrNO„+Aq.) and nitro codeine Tribromocodcine (C,„11,„Br,ICO.) has also been obtained ;and process similar to that for preparing iodomorphine. Ih-wdocodeine is a yellow crystalline precipitate formed on adding chloride of iodine to a strong solution of hydrochlotate of codeine. Cyanegen passed into a strong alcoholic solution of codeine is absorbed and after a time brilliant hexa gonal plates of a new base Cyanocodeine Cy,) arc deposited. Cyanocodeino forms crystalline salts with acids.
3. Thebaine (C,„H„NO.), so called from Thebes, an ancient city of Egypt, the alkaloid having probably been first obtained from Egyptian opium. Pelletier thought it only an isomeric modification of morphine, and hence called it paramorphine. Its position among, and the method its separation from, the other alkaloids, have already been indicated. It is net, like papaverine, precipitated from solution by subacetate of lead, but on separating the lead by sulphuric acid and adding slight excess of ammonia; it is then thrown down, and may be rendered colourless by treatment with animal charcoal and recrystallisation from alcohol.