This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Morphiae Sulphas. U. S. - This salt is most used in the United States. It is prepared by mixing morphia with water, gradually dropping in diluted sulphuric acid till the powder is dissolved, and then evaporating and crystallizing. It is in beautifully white, minute, soft, feathery crystals, very bitter, readily soluble in water, and slightly so in alcohol. It is known to be a sulphate by yielding with chloride of barium a white precipitate insoluble in nitric acid. It may be given in pill or solution, in the dose of from one-eighth to one-quarter of a grain.
Solution of Sulphate of Morphia (Liquor Morphiae Sulphatis, U. S.) is directed by our officinal code to be prepared by dissolving eight grains of the sulphate in half a pint of distilled water. It of course contains one grain of the salt in each fluidounce. Though the solution becomes gradually coloured by time, I have found it perfectly efficient, upon trial, after having been kept a year or longer. It has the great advantage of easy divisibility, as regards the dose, to any desirable minuteness. For full anodyne and soporific effect, the dose is from one to two fluidrachms. From one-quarter to one-half the quantity may be totaled in the form of spray, to relieve irritation of the air-passages The solution is too feeble for subcutaneous exhibition; as from ton to twenty or at most thirty minims of the menstruum should contain the quantity of the salt to be injected.
It is to be regretted that this solution, as kept in the shops, is not always of the officinal strength. In some parts of the country, a solution containing 16 grains to the fluidounce has been habitually employed. This may readily lead to serious mistakes. The physician should always specially designate the stronger solution when he intends it; and the officinal solution should always be put up by the apothecary, when the simple officinal name is used.