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 rhubarb, 2 fluidounces.
Simple elixir, 14 fluidounces.
Carbonate of magnesium, a sufficient quantity.
Triturate the fluid extract of rhubarb in a capacious mortar with carbonate of magnesium in amount sufficient to form a creamy mixture, then gradually add the simple elixir, stirring well, and filter.
Each fluidrachm of the finished elixir represents seven and one-half minims of fluid extract of rhubarb.