Origin. - A liquid composed of 68 per cent. by weight of absolute nitric acid (HNO3 == 62.89) and 32 per cent of water.

Description and Properties. - A colorless, fuming liquid, very caustic and corrosive, and having a peculiar, somewhat suffocating odor. Specific gravity about 1.403 at 25o C. (77o F.). Nitric acid should be kept in dark, amber-colored, glass-stoppered bottles.

Official Derivatives

Acidum Nitricum Dilutum - Acidi Nitrici Diluti - Diluted Nitric Acid. -Diluted nitric acid contains 10 per cent. by weight of absolute nitric acid. Dose. - 5-20 minims (0.3-1.2 Cc.) [30 minims (2 Cc), U. S. P.].

Acidum Nitrohydrochloricum - Acidi Nitrohydrochlorici - Nitrohydro-chloric Acid. - Formula: Nitric acid, 180; hydrochloric acid, 820 parts.

Description and Properties. - A golden yellow, fuming, and very corrosive liquid, having a strong odor of chlorine. Completely volatilized by heat. It readily dissolves gold-leaf, and a drop of it added to potassium iodide T. S. liberates iodine.

Dose. - 1-3 minims (0.06-0.18 Cc.) [3 minims (0.2 Cc), U. S. P.].

Acidum Nitrohydrochloricum Dilutum - Acidi Nitrohydrochlorici Diluti -Diluted Nitrohydrochloric Acid. - Formula: Nitric acid, 40; hydrochloric acid, 182; distilled water, 780 parts. - Dose, 5-20 minims (0.3-1.2 Cc.) [15 minims (1 Cc), U. S. P.].

Antagonists and Incompatibles. - Hydrochloric acid and its preparations are incompatible (forming explosive compounds) with oxidizable substances - phosphorus, sulphur and the sulphides, alcohols, ethers, carbohydrates, etc. All the mineral acids are incompatible with the alkalies and their carbonates, salts of lime, lead, and silver, and decompose glycosides.

Synergists. - The action of hydrochloric acid upon the digestive system is aided by the digestive ferments and the vegetable bitters.

Physiological Action. - The general action of mineral acids upon the various systems is herewith given in detail:

Externally and Locally. - Applied in a concentrated form to the skin or to any tissue of the body, acids abstract the water from the tissues and destroy the protoplasm, acting as escharotics. Weaker solutions vesicate, merely inflaming the parts to which they are applied, without destroying the tissue, while extremely diluted or weak solutions are irritant and astringent.

Internally. - Digestive System. - Diluted acids only should be administered internally. Save with reference to the poisonous effects of concentrated acids, therefore, the physiological action of diluted acids only will be here considered.

The salivary glands are stimulated, resulting in an increased flow of saliva, moistening the mouth and allaying thirst. The appetite and digestion are improved, and the secretions from the liver and the duodenal glands are increased. Long-continued use of the mineral acids impairs digestion by lessening the normal secretion of the gastric glands, while protracted use may produce salivation and a train of symptoms - anemia, loss of flesh, etc. Mineral acids tend to constipate.

Circulatory System. - Diluted acids in medicinal doses cause a rise in blood-pressure and increased action of the heart, probably due to their stimulating action on the vasomotor mechanism. Concentrated acids relax the muscular tissue of both the heart and blood-vessels. Mineral acids combine with the albumin or the alkaline bases of the blood, lessening the alkalinity of that fluid.

Nervous System. - Medicinal doses, so far as observed, produce no special action upon the nervous system.

Respiratory System. - No important action under medicinal doses has been observed.

Absorption and Elimination. - Mineral acids, above all hydrochloric acid, are readily absorbed. Diluted acids are converted into neutral salts in the intestines, and are absorbed as such. The excess of the acid which does not enter into combination in the stomach and intestines is rapidly absorbed into the blood, combining with its alkaline bases, and in this form is excreted, principally by the kidneys, as acid salts.

Temperature. - Medicinal doses have no influence upon temperature.

Untoward Action. - Mineral acids under too-prolonged administration impair the appetite and disturb digestion, occasioning toothache and gastric oppression, and at times salivation and diarrhea. They may also produce anemia, paleness of skin, and loss of flesh (Nothnagel and Rossbach). When taken for long periods and in comparatively large quantities they have a distinct degenerative action on the heart, the liver, and the kidneys. The prolonged use of nitric acid may produce erosion of the gums and tongue, with loosening of the teeth. Chromic acid and osmic acid act very energetically on the parenchyma of the kidneys.

Poisoning. - The mineral acids when taken in a concentrated form and in toxic doses act as corrosive poisons, causing intense burning in the stomach and intestines and active gastric inflammation. Violent vomiting occurs, the ejected matter containing blood, and, in the case of hydrochloric acid, a white cloud of ammonium chloride is discerned if the ejecta be placed near the vapor of ammonia.

The respiration is greatly depressed, and there is a strong, persistent acid taste in the mouth, the mucous membrane of which is discolored, while the tongue is swollen and inflamed. There is great thirst, and the pulse becomes rapid and tense. The temperature, at first elevated, soon falls below normal, profound prostration supervening, and death resulting either from shock or from secondary inflammation.

A postmortem examination shows the results of corrosive poisoning: ulceration or evidences of intense inflammation of the mucous membrane of the mouth, esophagus, stomach, and intestines. Occasionally the walls of the latter are perforated. Should death be delayed for some time, fatty degeneration of the kidneys and other internal organs is found.