This section is from the "Elixirs And Flavoring Extracts. Their History, Formulae, & Methods of Preparation" book, by John Uri Lloyd. Also available from Amazon: Elixirs and flavoring extracts,: Their history, formulae, and methods of preparation;
Fluid extract of buchu, 2 fluidounces.
Simple elixir, 16 fluidounces.
Carbonate of magnesium, a sufficient quantity.
Triturate the fluid extract of buchu with carbonate of mag-nesium in sufficient amount to form a creamy mixture, then gradually add the simple elixir, and filter.
According to this formula each fluidrachm should contain the active principles of seven and one-half minims of fluid extract of buchu. But, as a matter of fact, that amount will not dissolve in that quantity of the menstruum, the excess remaining in the filter paper. In our opinion, fluid extract of buchu should be made with alcohol of the specific gravity 0.820, and the addition of water lessens its value as a menstruum for extracting buchu and retaining its desirable principles, in proportion to the amount of water added. Hence it is that the elixir of buchu is inferior to an equivalent amount of the fluid extract of buchu used in making it, providing the fluid extract was reputable.