[In the Pharmacopoeia of the U. S. the troy pound is employed, and the divisions, with their signs annexed, are given in the fol-lowing table: -

The pound lb. The ounce The drachm The scruple contains twelve ounces, eight drachms, three scruples, twenty grains, gr.

The term pound, however, is disused and the weight is expressed in ounces, each containing four hundred and eighty grains. The drachm and scruple arc also disused, and replaced by their equivalents in grains. The weight of the grain is the same in both the Br. and the U. S. Pharmacopoeia. The avoirdupois oz. of the former contains but 437.5 grains or 42.5 less than the troy ounce, while the troy lb. contains 5760 grains or 1240 grains less than the avoirdupois pound. In the measures, instead of the imperial pint weighing 8750 grains of water at 62° F. and at a barometric pressure of 30 inches, the U. S. Ph. adopts the old wine measure, which weighs 7289.725 grains of water, under similar precautions, that is, 1460.225 grs. or about 1/6 less than the pint of the Br. Ph., and its measures are always expressed in pints or parts of a pint. Again, in the U. S. Ph.,

The pint, O

The fluid ounce The fluid drachm contains sixteen fluid ounces, eight fluid drachms, sixty minims, m.

Relation Of Weights Of The British Pharmacopceia To Metrical Weights

Relation Of Measures Of The British Pharmacopceia To Metrical Measures

The following remarks concerning certain groups of pharmaceutic preparations contained in the British Pharmacopoeia may-prove of service to the reader, by enabling him to discover at a glance the nature of their more important general characters, and facilitating the understanding of some peculiarities in nomenclature and methods of preparation found in many of them.

Acida. Acids. Among this group, directions are found for making certain dilute acids, and the same rule has in most instances been followed; for example, Acidum Hydrochlorium Dilutum, Acidum Nitricum Dilutum, Acidum Nitro-hydrochlorium Dilutum, Acidum Phosphoricum Dilutum, and Acidum Sulphuricum Dilutum, will be seen to have nearly the same neutralising powers, measured, except in the case of dilute phosphoric acid, by the amount of an alkaline solution which they are capable of saturating. Acidum Sulphuricum Aromaticum, which is really a dilute acid, is somewhat weaker; and Acidura Aceticum Dilutum has been so formed as to assimilate it closely in strength with Acetum, or vinegar. Acidum Hydrocyanicum Dilutum hardly belongs to the same category of medicines, as it is not employed on account of its acid properties.

Aquce. Waters. The waters of pharmacy consist of water holding in solution very small quantities of oils or other volatile principles. In the British Pharmacopoeia two principal methods are adopted for making these preparations. In the first, the part of the plant is ordered to be placed with water in a retort, and a certain quantity of water brought over by distillation; this is the case with the dill, caraway, cinnamon, fennel, cherry-laurel, pimento, rose, and elder-flower waters.

The second method consists in distilling the volatile oils, previously obtained from the plants, with water; peppermint and spearmint waters are thus prepared.

Aqua Camphors, formerly termed Mistura Camphorse, is made simply by allowing water to dissolve as much camphor as it is capable of taking up; and Aqua Destillata is only water distilled with such precautions, as to ensure its freedom from any appreciable or important amount of foreign matters.

Cataplasmata. Cataplasms or Poultices. Cataplasms are soft, moist, local applications, employed sometimes solely for the sake of their moisture and temperature, but more frequently, in addition to these properties, on account of certain peculiar active remedies contained in them.

The basis of the cataplasms in the British Pharmacopoeia is linseed meal, either alone, or united with bread or flour; boiling water is employed for mixing the ingredients, except in the case of Cataplasma Fermenti, when water at 100° Fah. is made use of, in order that the catalytic powers of the ferment may not be injured by the heat. Olive oil is added to the Cataplasma Lini as a substitute for the natural oil which has been removed from the linseed by expression.

Confectiones. Confections, Electuaries, or Conserves. Confections are used sometimes merely as a basis for pill masses, etc, sometimes for the exhibition of sparingly soluble remedies which require to be administered in bulky doses. Honey or sugar, or both these substances, form a prominent part of all confections.

Decocta. Decoctions. A decoction is a watery solution of a medicinal substance prepared by boiling. The length of time ordered in the Pharmacopoeia is in most instances from ten to twenty minutes; in some cases boiling for an hour is directed, and, in one instance, Decoctum Granati Radicis, two pints are to be reduced to the bulk of a pint. The length of time should be proportionate to the solubility of the active matter of the drug; but prolonged boiling is often objectionable from rendering this portion less active, or even inert. In two decoctions only, namely, Decoctum Aloes Compositum and Decoctum Sarsae Compositum, are the preparations made compound by the introduction of more than one active drug. Only those medicines should be used in the form of decoction which contain active principles not injured by the boiling temperature; if volatile oils are present, these are dissipated in the process. Decoctions should be strained when hot, as a deposit of active matters occasionally takes place when the preparation becomes cold, as in Decoctum Cinchonas Flavae.