Crystallized sulphate of iron, 256 grains.

Bicarbonate of sodium, 200 grains.

Citric acid, distilled water, of each a sufficient quantity.

Dissolve the bicarbonate of sodium and the sulphate of iron separately, each in sixteen fluidounces of cold, freshly distilled water, and mix the solutions; pour the mixture into a bottle, which must be filled to the stopper, using more distilled water if necessary, and permit it to rest for twenty four hours. Decant the clear solution and refill the bottle with freshly distilled water, shaking well, and permit it to stand as before. After twenty-four hours decant the solution, pour the residue upon a fine muslin strainer and squeeze the liquid from it. Dissolve the precipitate by trituration in a mortar with citric acid in sufficient amount, and then add enough simple elixir to make sixteen fluidounces, and filter.

Each fluidrachm (teaspoonful) of the finished elixir contains of citrate of protoxide of iron an amount which is equivalent to two grains of crystallized sulphate of iron. The name "elixir of protoxide of iron" is a misnomer. It is the elixir of a salt of protoxide of iron.

Among the first of the modern elixirs introduced to the medical profession was one under the name "elixir of bark and protoxide of iron." This preparation is private property, and we are not acquainted with the formula and process employed in making it. Since its introduction this elixir has enjoyed a popularity which commands for it a constant sale among physicians, and we caution physicians against confusing it with the elixirs we give formulae for, and which are not elixirs of protoxide of iron, although in commerce they have acquired that title.