ACIDUM FLUORICUM, Fluoric Acid, HF (Unofficial), -is a strong escharotic, acting deeply and leaving a dry and painful slough. The dilute acid (1 in 200) is prepared by acting on fluor spar by Sulphuric Acid, the resulting gas being dissolved in water. Its dose is mxx-xxx, well diluted.

Dilute Fluoric Acid has been successfully used as an internal remedy in goitre, and the gas has been inhaled with benefit in diphtheria and membranous croup.

ACIDUM GALLICUM, Gallic Acid, HC,H,O,. H,O,—is a nearly colorless solid in long needles or triclinic prisms, having a slightly acid and astringent taste, soluble in 100 of water and in 4%1⁄2 of alcohol at 59° F., and in 3 of boiling water. It is prepared from a paste of powdered galls (see GALLA), by fermenting for six weeks, boiling and reboiling in water, filtering and crystallizing. According to some authorities. the Tannic Acid of the galls is split up into Gallic Acid and glucose. by fermentation; but according to others the glucose is an impurity and the Tannic Acid is simply converted into two parts of Gallic Acid, C1H10O9 + H2O (HC,H,O). Dose, gr. v-xv, in solution, pill or powder.

=

ACIDUM PYROGALLICUM, Pyrogallic Acid, Pyrogallol, Tri-hydroxybenzene, CH(HO), (Unofficial), -is obtained from Gallic or Tannic Acid by careful heating. Dose gr. j-ij.

Preparations.

Unguentum Acidi Gallici,—is a 10 per cent. ointment, with a basis of Benzoinated

Lard.

Vegetable Astringents depend for their medicinal value upon the Gallic and Tannic Acids contained in them. Such are

GALLIC ACID, and its congener Tannic Acid, are astringents, the former being the more feeble of the two. They differ in that Tannic Acid coagulates albumen and gelatin, while Gallic does not. Tannic Acid is converted by the organism into Gallic and Pyrogallic Acids, in which forms it is absorbed and excreted. According to some authorities the difference between Gallic and Tannic Acids is one of oxidation, according to others of hydration; the latter assuming Tannic Acid to be simply Gallic Acid

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Anhydride. They constringe the muscular tissue in the walls of the minute vessels, thus checking secretion and hemorrhages and cutting short local inflammations. Except in enormous doses they are harmless. [Compare ACIDUM TANNICUM.]

PYROGALLIC ACID may act as an intense poison, having been absorbed from the surface with fatal results, preceded by vomiting and diarrhoea, rigors, and fever, black urine full of globulin, and disorganization of the blood-corpuscles. It has great affinity for oxygen and may be used as an antiseptic and disinfectant in 1 to 21⁄2 per cent. solutions.

Antagonists and Incompatibles.

Mineral acids, alkalies, per-salts of iron, and salts of antimony, lead, and silver are chemically incompatible.

THERAPEUTICS.

GALLIC ACID is preferred to Tannic Acid when an astringent action is desired upon remote parts, as the lungs, kidneys, etc., which can only be reached through the circulation. In hematuria, distant passive hemorrhages, albuminuria, diabetes insipidus, bronchorrhoea, night-sweats, chronic diarrhoea, and chronic cystitis, it is a most useful remedy.

PYROGALLIC ACID has been used internally in two-grain doses for internal hemorrhages. As an ointment (3j-3j) it is next to Chrysarobin as an efficient palliative in psoriasis, and has been used with good results in lupus and epithelioma, being supposed to attack the diseased nodules only, leaving the adjacent skin uninjured.

ACIDUM HYDROBROMICUM DILUTUM, Diluted Hydrobromic Acid,-is composed of 10 per cent. of absolute Hydrobromic Acid (HBr), and 90 per cent. of water. It is a clear, colorless, and odorless liquid, of a pungent acid taste, produced by decomposing Potassium Bromide by Sulphuric Acid and distilling. Dose, mxx-zij, every three hours.

Hydrobromic Acid has identical action on the nervous system and circulation with that of the Bromides. Added to a mixture of Quinine and water (mij to each grain of Quinine) it will produce a clear solution.

In hysteria, congestive headaches, neuralgia, and nervous exhaustion, Hydrobromic Acid has been found useful. Used as a solvent of Quinine it retards cinchonism, and prevents the headache resulting from the full action of Quinine and Iron. As a substitute for the Bromides of Sodium and Potassium it is highly recommended, being much less depressant. It has been especially recommended in tinnitus aurium. Fothergill uses it for coughs of reflex or spasmodic nature, also for simple continued fever where there is cerebral disturbance.

ACIDUM HYDROCHLORICUM, Hydrochloric Acid, Muriatic Acid,-is a liquid composed of about 32 per cent. of absolute Hydrochloric Acid Gas, HCl, and 68 per cent. of water. It is colorless and fuming, of specific gravity 1.160, pungent odor, intensely acid reaction and taste, and is obtained by the action of Sulphuric Acid upon Sodium Chloride, the resulting gas being carried through water which dissolves it. It is sometimes used as a caustic. Its union with basic substances forms salts, called Hydrochlorates (Muriates), of which four are official, viz.: the Hydrochlorates of Apomorphine, Morphine, Pilocarpine, and Quinine, described under the titles of their respective bases.

Preparations.

Acidum Hydrochloricum Dilutum,-is a 10 per cent. solution of the absolute acid in water. Dose, miij-x.

Acidum Nitro-hydrochloricum,-see under Acidum Nitricum.

PHYSIOLOGICAL ACTION OF THE MINERAL ACIDS.

The mineral acids (Hydrochloric, Sulphuric, Nitric, Nitro-hydrochloric, and Phosphoric) resemble each other in general action so closely that they may all be described in this place.

The strong acids are escharotic, abstracting the water of the tissues, combining with the albumen and other bases, and destroying the protoplasm. They are very diffusible, redissolving the albumen after precipitating it (except Nitric Acid). Sulphuric and Phosphoric have a strong affinity for water, completely decomposing tissues to which they are applied, and are therefore the most powerfully escharotic. Nitric Acid does not readily redissolve the albumen precipitated by it, which thus forms a barrier against the deep action of the acid. Sulphuric Acid chars or carbonizes the tissues black, while Nitric and Hydrochloric tan them yellow.

The dilute acids produce a peculiar taste in the mouth and a sensation of roughness on the teeth. They stimulate the flow of saliva from the parotid and submaxillary glands, but have no action on the sympathetic saliva. They promote the alkaline intestinal secretions and excite the flow from ducts having an alkaline secretion (bile, etc.), but check that from those whose secretion is acid (gastric, etc.). Secretion generally is promoted by Nitric Acid, and lessened by Sulphuric, Hydrochloric acting between the other two. Given before meals, in small doses, they relieve acidity of the stomach by checking the production of the acid gastric juice. At first they aid digestion, being synergistic to the action of pepsin, but if continued they impair digestion by lessening the production of the gastric juice. They check fermentation and constipate the bowels, except Nitric Acid, which relaxes them. They render the urine slightly more acid than its normal reaction, but do not acidify alkaline

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urine as the vegetable acids do. They are all astringent to the tissues, Hydrochloric being weakest and Sulphuric the strongest in this respect.

Antagonists and Incompatibles.

Alkalies to neutralize the acid; oil, albumen, or milk, to protect the mucous membrane; stimulants, Opium, Ammonia (intravenously) to combat the resulting depression of the vital powers.

THERAPEUTICS OF THE MINERAL ACIDS.

All the members of this group are useful in fevers, if well diluted, Hydrochloric being usually preferred, especially in typhoid. In atonic dyspepsia, acidity of the stomach, and locally in ulcerations of the throat, Hydrochloric Acid is best used. Nitric is the acid generally preferred as a caustic, its action being effectual and superficiál. As such it is applied undiluted to phagedenic ulcers and sloughs, warty growths, and to the cavity of the womb in chronic inflammation thereof. Dilute Nitric Acid is used internally in oxaluria and lithemia, intermittent and remittent fevers, and aphonia of singers. Dilute Nitro-hydrochloric is more suitable in chronic hepatic disorders due to malaria; Sulphuric in hemorrhages, diarrhoeas, colliquative sweating, and as a prophylactic against leadpoisoning. Dilute Sulphuric Acid is used as an acid drink in fevers, and before meals in acidity of the stomach. It is very doubtful whether the latter has any special influence on the nervous or osseous systems.

All these acids act injuriously on the teeth, by attacking the enamel. They should always be administered largely diluted, taken through a straw or glass tube, and the mouth should at once be thoroughly rinsed with an alkaline solution.

ACIDUM HYDROCYANICUM DILUTUM, Diluted Hydrocyanic Acid, Prussic Acid,—is a liquid composed of 2 per cent. of absolute Hydrocyanic Acid, HCN, and 98 per cent. of alcohol and water. It is colorless, faintly acid, of peculiar odor, and is prepared by distilling solutions of Potassium Ferrocyanide and Sulphuric Acid together, or extemporaneously by adding 6 parts of Cyanide of Silver to a solution of 5 parts of Hydrochloric Acid in 55 of distilled water, shaking together and pouring off the supernatant liquid. mxl have proved fatal. Dose, mj-v.

Preparations containing Hydrocyanic Acid.

Aqua Laurocerasi, Cherry-laurel Water (Unofficial),-is a water distilled from the fresh leaves of Prunus laurocerasus, the common Laurel or Cherry Laurel, a small tree of the nat. ord. Rosaceæ, sub-order Amygdaleæ. The leaves contain a variable amount of Hydrocyanic Acid and a volatile oil. Dose, m v-xxx, cautiously.

Scheele's Dilute Hydrocyanic Acia (Unofficial),—is a 4 or 5 per cent. solution, and is highly dangerous even by inhalation.

Amygdala Amara, Bitter Almond (see its title) and its essential oil; also, various other members of the sub-order Amygdaleæ, including the official Prunus Virginiana, perhaps the unofficial Prunus laurocerasus, and the leaves and kernels of the peach and cherry trees, contain a proximate principle Amygdalin, and a ferment Emulsin, which in the presence of water react with each other, forming Hydrocyanic Acid, a volatile oil, and glucose. C20H27NO11 (Amygdalin) + 2H,O — C,H ̧O (Oil of Bitter Almond) + HCN (Hydrocyanic Acid)+2C6H12O6 (Glucose).

Other Cyanogen Compounds.

Potassii Cyanidum, Cyanide of Potassium, KCN,—a white, opaque salt, of alkaline reaction, bitter-almond taste and a peculiar odor when moist; soluble in 2 of water at 59° F., sparingly soluble in alcohol. Dose, gr. 2. Locally a solution of gr. j-v to the 3.

Potassi Ferrocyanidum, Ferrocyanide of Potassium, K,Fe(CN)63H,O,—large, lemon-yellow prisms or tablets, efflorescent, odorless, of sweetish taste and neutral reac tion, soluble in 4 of water, insoluble in alcohol. Employed in pharmacy as a test solution, and in the preparation of Ferrocyanide of Iron, Diluted Hydrocyanic Acid and the Cyanides of Potassium and Silver. Rarely used medicinally. Dose, gr. v–xv.

PHYSIOLOGICAL ACTION.

PRUSSIC ACID is one of the most powerful and rapid poisons known, half a grain having proved fatal. Its action on the organism is one peculiar to itself, the inhalation of a strong preparation producing rapid insensibility and almost immediate exhaustion ;-death from a full dose occurring by sudden paralysis of the heart, from a less but still a fatal dose, by paralysis of respiration. The symptoms are those of sudden and complete asphyxia, and some volitional movements may be made before death, unless the dose be very large. In cases in which the dose, though fatal, permitted of the observance of its effects, they were usually divisible into two marked stages, viz.: (1) Dyspnoea, slow and full pulse, giddiness, loss of muscular power. (2) Vomiting, dilated pupiis, unconsciousness, spasms, muscular rigidity, and cessation of the heart's action. In poisonous, but not fatal doses, the following effects have been observed: feeble pulse, dilated pupils, turgid and dusky face, insensibility, convulsions or rigidity, but no paralysis. Large medicinal doses may produce salivation, irritation of the throat, dizziness, buzzing in the ears, headache, numbness, dusky countenance, staggering gait, sense of constriction of the chest, palpitation of the heart, a frequent or an abnormally slow pulse, a sense of great weariness and drowsiness. Post-mortem examination shows usually dilated pupils, the eyes having a marked glassy lustre, the cadaveric rigidity very great. The blood, in cases which have been rapidly fatal, may show the arterial color in both the arterial and the venous systems; but in slower cases it is dark and fluid, engorging both sides of the heart, the venous trunks, and the cerebral sinuses. The paralyzant action of the drug is chiefly exercised on the nerve-centres in the medulla; next on the peripheral afferent nerves, the spinal cord, the motor nerves, and finally on the muscular tissue. It stops the heart by irritation of the vagus-roots in the medulla, as well as by paralyzing the