Codex @codex  0

The 1864 solid units are the avoirdupois pound, avoirdupois ounce and grain; the liquid units are the Imperial measures. The grain is unchanged, while the old apothecaries' pound and ounce are not the units of the new formulary. ^[ref]

The relations for solids areTheir approximate French metric equivalents are:

For liquids,The approximate metric volumes are:

A millilitre is a cubic centimetre, and a litre is a cubic decimetre. These displayed equivalents are rounded; small differences from a period table's last digits reflect rounding and historical calibration conventions. A fluid ounce is a volume and an avoirdupois ounce is a mass. They cannot be interchanged for an arbitrary liquid without its density. Likewise, a drop is not a defined minim: its volume depends on the liquid and the dropper.

The 1864 preparations contain either crude opium or its aqueous Extractum Opii; those quantities must be distinguished from a quantity of isolated morphine. The following are the officinal opium preparations. Ratios for solids mean the mass fraction in the compounded preparation; liquid strengths specify mass per volume or the actual ingredients used.

The arithmetic uses the new avoirdupois ounce of 437.5 grains, not the old apothecaries' ounce of 480 grains. These are historical formulation proportions, not modern assays of morphine delivered after solvent extraction. Confectio Opii was omitted in 1864, and this edition's Vinum Opii contains no spices. The separate morphine hydrochloride preparations—Liquor Morphiae Hydrochloratis, Suppositoria Morphiae, Trochisci Morphiae, and Trochisci Morphiae et Ipecacuanhae—contain an isolated alkaloid salt rather than crude opium. ^[ref]

The principal period groups were digitalis preparations, squill, broom, juniper oil, buchu, nitrous ether spirit, and several soluble potassium salts. They were grouped by observed promotion of urine flow, rather than by one common mechanism. The following are historical adult quantities per administration, expressed in the contemporary units; they are not present-day prescriptions.

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Other recognised period agents included dandelion and copaiba. The dandelion decoction was given in quantities of 1–2 fluid ounces, its soft extract in quantities of 10–30 grains, and its preserved juice in quantities of ½–2 fluid drachms. Copaiba was given in quantities of 15–30 minims, and copaiba oil in quantities of 5–20 minims. Their historical inclusion does not establish that they are suitable substitutes for current diuretic therapy. ^[ref]

The distinction between preparations matters more than a single “dose of the plant”: an infusion, tincture, juice and powder have different concentrations. Likewise, a salt's small historical diuretic dose is not its larger purgative dose. A modern explanation also separates a direct effect on renal tubules from improved cardiac output in appropriate heart failure: digitalis preparations cannot be understood simply as agents that make every kidney excrete more water. Modern digoxin is used for selected cardiac indications, rather than as a general treatment for low urine output. ^[ref]

The seven named mixtures of the 1864 British Pharmacopoeia are Mistura Ammoniaci, Mistura Amygdalae, Mistura Creasoti, Mistura Cretae, Mistura Ferri Composita, Mistura Guaiaci and Mistura Scammonii. Their compositions are as follows; avoirdupois ounces are used for solids and fluid ounces for liquids.

The category is an official preparation name, not every possible bedside combination of medicines. Camphor water and acacia mucilage are not additional entries under Mistura: the 1864 names are Aqua Camphorae and Mucilago Acaciae. ^[ref]

The 1864 iron list includes metallic, ferrous, ferric and compound preparations; its wet Ferri Peroxidum Hydratum was used historically as an antidote to arsenic poisoning. It must be distinguished from dried Ferri Peroxidum and from later editions' reassignment of similar Latin names.

The officinal articles and preparations are:

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Prepare the hydrated peroxide by inducing precipitation from the ferric solution with sodium hydroxide, collecting and washing the wet precipitate, and preserving it without drying in a covered vessel. The starting solution is Liquor Ferri Persulphatis, whose “persulphate” here means ferric sulfate, not a modern peroxydisulfate salt. Add the appropriately diluted ferric solution to the alkaline liquor with stirring, allow the precipitate to settle, collect it on a calico filter, and wash with distilled water until the washings no longer give a precipitate with barium chloride. This tests removal of soluble sulfate. The resulting fresh, hydrated material is kept wet; drying gives the separate dried preparation. ^[ref]

In modern chemical notation the precipitation can be idealised asThe fresh solid is a hydrated ferric oxide material with variable water content; the equation is not a claim that every pharmaceutical batch is one pure, crystalline iron hydroxide. Its historical use depended on binding dissolved arsenic into less available material in the digestive tract, especially the freshly precipitated, wet state. It was not a universal antidote to every metal or every stage of absorbed arsenic poisoning. Contemporary discussion explicitly identified the new hydrated peroxide as an arsenic antidote. ^{[ref] [ref]}

Modern treatment of significant arsenic poisoning concerns systemic toxicity and may involve specialist-directed chelation therapy; a nineteenth-century ferric paste is not the modern treatment standard. ^[ref]

Decoction suits material whose useful constituents are water-soluble and withstand boiling; infusion avoids sustained boiling and can better preserve delicate or volatile constituents. The choice depends on both the plant's structure and the chemistry of the constituent being extracted.

Hard bark, wood and many kinds of root need comminution and more prolonged contact with hot water to penetrate their tissues; a decoction can assist extraction when the desired material is stable. Boiling is unsuitable when it drives off a needed volatile oil, decomposes the active constituent, or extracts an unwanted excess of starch or other material. A hard root is therefore not automatically an instruction to boil. Period examples suitable for decoction include oak bark, logwood and pareira root; appropriate infusions include aromatic cloves and chamomile. Cold infusion of calumba avoids dissolving its starch, illustrating that suitability depends on the desired selectivity of solvent extraction, not merely on whether a drug is a leaf or a root. ^[ref]

For an infusion, the appropriately divided drug is left in a measured solvent for a prescribed time, commonly in a covered vessel. Hot water assists extraction, while a cover reduces loss of volatile matter. Cold infusion can be chosen when heat is undesirable. The result must be strained or filtered; time, temperature, particle size and solvent quantity affect its strength. Neither method guarantees that every constituent is extracted in the same proportion.

A liquid extract is made by extracting the specified drug with a suitable solvent, separating the liquid from the exhausted material, and bringing the extract to its prescribed concentration and volume. Maceration can precede percolation; expression or washing recovers retained liquid. A percolator passes fresh solvent through a packed bed, rather than indefinitely soaking the drug in an increasingly saturated liquid. Where concentration is necessary, controlled evaporation limits damage; an alcoholic fraction can be reserved or recombined as the monograph directs. Different liquid extracts can use aqueous, alcoholic or ethereal processes. For example, the liquid extract of male fern is an ethereal extraction of a resinous and oily fraction, whereas the liquid extract of opium is compounded from a previously made aqueous extract. These are chemically different operations. There is no warrant for assigning all 1864 extracts one modern universal drug-to-extract ratio. ^[ref]