General Priciples:. Starting with crude drugs, the next step is to qualify them for medicinal use. This involves two forms or conditions into which drugs are to be brought, the fluid form and the dry form, to be governed by the following directions and principles. All substances, soluble in the previously described menstrua or vehicles, are properly to be made into solutions or tinctures and their dilutions, also such moist and soluble substances may be made into triturations with milk-sugar. But all insoluble or only partially soluble substances should be made into triturations only.

Aqueous Solutions:. Are made of substances which are soluble in water but not in alcohol, or of those which, when soluble in alcohol, are subject to chemical change or decomposition. These are to be dissolved in the proportion of 1/10 ,1/100, or 1/1000 depending upon the degree of solubility of the substance. Aqueous Solutions are, as a rule, unstable and will keep but for a short time.

Solutions of Fluids in Alcohol:. These are equivalent to tinctures, and are made of substances which yield wholly or in part their medicinal properties to alcohol. This applies to liquids like turpentine, oils etc. These are to be made on the decimal scale, that is, in the proportion of 1 part by weight of medicinal substance to be added to sufficient alcohol to make 10 parts by volume, and hence equal to the first decimal dilution, to be marked 1x. If not soluble in the proportion of 1 to 10, they should be made by adding 1 part by weight of drug to 99 parts by volume of alcohol, and the product marked 2x. Such solutions are also to be made of alcohol of known strength, in order that the same may be employed in making the succeeding dilution, and also that it may dissolve all that is soluble, and prevent decomposition. If liquid acids or drug contain water, this should also be deducted from that contained in the solvent, and the anhydrous acid or drug taken as the unit of strength.

These are made from a variety of substances, which are wholly or partially soluble in alcohol. Such substances comprise all plants and parts of plants, such as barks, roots, wood, fruits, and seeds, resins, gums and balsams. The list should also include minerals and chemicals which dissolve more readily in alcohol than in water.
     Substances such as phosphorus, and also volatile salts, are better prepared as solutions (tinctures) than as triturations, in the making of which they are volatilized and destroyed.
    As most tinctures are made from plants or their parts, their treatment deserves special mention. It is very important that tinctures should be of uniform strength, instead of varying greatly on account of the variability of water contained in the same plant at different seasons and conditions of growth and protection. The variability of water in the solvents, especially in alcohol, has also added to the variability of tinctures and of the dilutions made from them causing great uncertainty in practice. Hence, the following rules were first devised in the “ British Homoeopathic Pharmacopoeia”, which were adopted by American Pharmacopoeia and also retained in this work.
    Fresh succulent plants and other substances containing water should be so treated, according to the fundamental rule, that the dry crude drug is taken as the starting point from whence to calculate the strength of the tincture. Hence, the pharmacist is to proceed by first taking a suitable quantity of fresh plant or other substance containing moisture. He is to weigh the same, and then to dry it by gentle heat of the water-bath until the scale indicates no further loss of weight. There upon the difference of weight between the fresh and dried plant substance will clearly indicate the weight of moisture evaporated, for which allowance must be made in the preparation of the menstrua. The dry crude material after evaporation is taken as unit of strength, the tincture being made to represent 1 part of the dry crude material in each 10 parts of completed solution. It is, however, to be understood that the fresh green plant is to be used in the preparation of the tincture when so specified in part II.
     Having determined how much of dry substance is contained in the given quantity of the fresh moist material (say 10 Gm), this is to be compared with the special tincture formula for this drug (Part II). If its weight is below that given as the standard in the formula, add enough distilled water to the moist magma to equal the standard weight. If, on the contrary, the weight of the moist drug-substance exceeds the standard of the formula, deduct enough from that intended for the dilution of the solvent alcohol, then reduce it to the standard weight. Or, when, for practical reasons, this cannot be done, resort to the slower method of evaporating, by cautious drying in moderate temperature enough of the drug-moisture to reduce it to the standard of the formula. In this process, both in the case of deficiency and of axcess water in the drug, it is to be remembered that the tincture finally consists of alcohol and its proportion of water, plus that of the drug-substance dissolved. The preparation of tinctures is then continued according to one of the following processes of maceration or percolation.

Maceration      Percolation