It is not uncommon, .in fact it is a common practice among pharmacists to prepare tinctures needed from time to time by dilution of fluidextracts. In some cases this procedure is warranted, as may be seen by taking into consideration the percentage of alcohol in either preparation and also the solubility of the active agents in varying strengths of alcohol. When tinctures are needed for immediate use, or for those which have a limited demand in everyday practice, they are commonly made from the

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... fluidextract without considering the result of such dilution. Qluidextracts are usually a t hand, and dilution of them therefore is an easy method for making tinctures on short notice, but the resulting preparations of some of these are questionable. A few examples will suffice to make clear the result of this procedure. Fluidextract of Aconite has an alcoholic menstruum composed of three volumes of alcohol and one of water, or 7 1 ' 3~ alcohol, while that of the tincture has seven volumes of alcohol and three of water, or 66.5% alcohol. The difference in alcoholic strength of the two menstrua is not so striking as in other cases and, since the activity of the preparation is dependent on the alkaloids present, the dilution of the standardized fluidextract may be used to advantage and in this case would not throw out of solution any of the active agents with so small a change in the alcoholic content. In the preparation of Tincture of Cannabis from the fluidextract there could be no serious objection to the common practice of dilution, inasmuch as the alcoholic content in the two preparations is the same. In preparations of Calumba the activity is due in part to a small alkaloidal content, also to gum and resin. The fluidextract U. S. P. VIII contains 66.5Tc and the tincture 577& alcohol. It will readily be seen why in this dilution, involving the solution of gum and resin, a precipitate forms so that the resulting preparation does not represent the extractive matter obtained in a tincture made by the usual method.