 Solution

Pulvis Jalapae Compositus contains powdered jalap 5 avoirdupois ounces, potassium hydrogen tartrate 9 avoirdupois ounces, and powdered ginger 1 avoirdupois ounce. Thus the mass proportions are 5:9:1, and jalap supplies one third of the powder's mass. This is a compound purgative, not pure jalap resin. ^[ref]

Pilula Scillae Composita contains powdered squill 1¼ avoirdupois ounces, powdered ginger, ammoniacum and hard soap 1 avoirdupois ounce each, with treacle 2 avoirdupois ounces, or sufficient to make a pill mass. Using the specified 2 avoirdupois ounces of treacle, the whole is 6¼ avoirdupois ounces and contains one fifth squill by mass. The allowance of sufficient treacle makes consistency a compounding requirement, not a claim that every moist pill batch has an analytically exact 20% squill content. ^[ref]

Liquor Morphiae Hydrochloratis contains morphine hydrochloride 4 grains, dilute hydrochloric acid 8 minims, rectified spirit 2 fluid drachms and distilled water 6 fluid drachms. Its conventional strength is ½ grain of morphine hydrochloride per fluid drachm, not ½ grain of free morphine. The small quantity of hydrochloric acid maintains an acid solution. ^[ref]

Liquor Strychniae contains strychnine 4 grains, dilute hydrochloric acid 6 minims, rectified spirit 2 fluid drachms and distilled water 6 fluid drachms. Dissolve the strychnine in the acid mixed with part of the water, using the prescribed assistance of heat, then add the spirit and remaining water. Its conventional strength is ½ grain of strychnine per fluid drachm. Acid promotes solubility by forming a soluble salt of the alkaloid. ^[ref]

For the last two solutions, the stated historical strengths use the nominal 8 fluid drachms of spirit and water. The extra few minims of dilute acid must still appear in the actual recipe; treating all ingredient volumes as perfectly additive would not give an exact modern analytical concentration.