FORM′ULA. [L.] In pharmacy and medicine, a short form of prescription; a recipe. By chemists the term is applied to a grouping of symbols, expressing the composition of a body; thus, HCl (standing for 1 atom of hydrogen united to 1 atom of chlorine) is the formula for hydrochloric acid. A chemical formula is termed empirical when it merely gives the simplest possible expression of the composition of the substance to which it refers. A rational formula, on the contrary, aims at describing the exact composition of molecule, or combining weight of the substance, but stating the absolute number of atoms of such of the elements essential to that object, as well as the mere relations existing between them. The empirical formula is at once deduced from the analysis of the substance, reckoned to 100 parts; the rational formula requires, in addition, a knowledge of its combining quantity, which can only be obtained by direct experiment, by synthesis, or by the careful examination of one or more of its most definite compounds. Thus, the composition of acetic acid is expressed by the formula CH2O, which exhibits the simplest relations of the three elements; if we want to express the quantities of these, in atoms required to make up one molecule of acetic acid, we have to adopt the formula C2H4O2 or HC2H3O2.
FOR′MYL. Syn. Formyle. A hypothetical organic radical, having the composition C2H. Its existence was inferred from the constitution of certain organic compounds which are now referred to the methyl-series. Formic acid was supposed to be an oxide of formyl; and chloroform, the terchloride of formyl.
FOXGLOVE. Syn. Digitalis (B. P.), L. A genus of plants belonging to the natural order Scrophulariacæ. The leaves of the uncultivated ‘Digitalis purpurea,’ or purple foxglove, are officinal in our pharmacopœias. They must be gathered before the terminal flowers have expanded. “The petiole and
midrib of the leaf being cut off, dry the lamina.” (Phar. L.) The seeds (DIGITALIS SEMINA), which were ordered, as well as the leaves, in former pharmacopœias, are said to be in many points preferable to them. When good, the leaves are of a dull-green colour, and possess a feeble narcotic odour, and a bitter, unpleasant taste. Both the dried leaves and the powder should be preserved in corked bottles covered with dark-coloured paper, or in well-closed tin canisters, and kept in a dark cupboard; and the stock should be renewed yearly, as age considerably diminishes the medicinal activity of digitalis.
Action, uses, &c. Foxglove is diuretic, sedative, and antispasmodic, and exerts a specific action over the cerebro-spinal system, promoting the functions of the absorbents, and reducing the force of the circulation in a remarkable manner. It is administered in fevers and inflammations, to reduce the frequency of the pulse, and to allay excessive vascular excitement; in dropsy (unless the habit is full and pulse tight and cordy), as a diuretic, either alone, or combined with squills, calomel, salines, or bitters; in internal hæmorrhages, as a sedative, when the pulse is full, hard, and throbbing; in diseases of the heart and great vessels, and in phthisis, to reduce the force and velocity of the circulation; in epilepsy and insanity, to repress vascular excitement; and in spasmodic asthma, scrofula, and several other diseases, with one or other of the above intentions.
The greatest caution is required in the use of foxglove, as its effects accumulate in the system, and the unwary practitioner is occasionally surprised at the sudden demise of his patient, even after he has left off the use of this drug.—Dose, 1⁄2 gr. to 11⁄2 gr., in powder, every 6 hours. See Extract, Infusion, Tincture, &c.
FOX′ING. See Malt Liquors.
FRACT′URE. Syn. Fractura, L. The breaking or disrupture of a bone. When the bone is nearly divided into two parts, it is called a SIMPLE FRACTURE; when the integuments are also lacerated, a COMPOUND FRACTURE; and when the bone is splintered, a COMMINUTED FRACTURE.
FRAGRANT PAIN-CURER (Five-minute). Dr Walter Scott, New York. A remedy to remove all kinds of pain in five minutes. A clear colourless fluid containing ether, 6 grammes; glycerin, 21 grammes; common salt, 3·4 grammes; distilled water, 170 grammes. (Hager.)
FRANK′INCENSE. Syn. Common frankincense; Thus (Ph. L.), L. The turpentine which exudes from the bark of Abies excelsa (Norway spruce fir) and Pinus palustris (pitch or swamp pine), hardened by the air. (Ph. L.) The gum-resin olibanum, which is the produce of the Boswellia thurifera, is the ‘odorous frankincense’ of commerce.