Acidum Oxalicum. HO, C2O3+2 HO. Is obtained chiefly by the action of Nitric Acid upon Sugar, or by exposing a mixture of sawdust with a solution of Hydrate of Soda and Hydrate of Potash to a temperature above 400° F.; but it exists largely in Oxalis and Rumex acetosella, Cicer arietinum, and other plants.
Med. Prop. and Action. Refrigerant and sedative in very small doses largely diluted; but it is inferior in efficacy to Citric or Tartaric acid, and much more dangerous. In large doses it is a powerful irritant poison: two drachms have been known to destroy life. When taken internally, it is absorbed into the system, and has been detected in the blood, in the substance of the heart, and in the urine; in the latter it is found in combination with an alkali. Dr. Prout says that it passes through the kidneys unchanged. When taken in a large dose, or in a concentrated state, it produces an intensely sour taste, heat in the throat, a burning sensation in the stomach, vomiting, sometimes of bloody, at others of greenish-brown, or black, grumous matter. Collapse follows, pale and anxious countenance, cold clammy skin, &c. Convulsions sometimes occur before death. The most characteristic post-mortem appearances are a white or shrivelled state of the mucous membrane of the mouth, fauces, oesophagus, and stomach, the membrane being more or less softened, and readily detached. The vessels ramifying on the surface are filled with blackish Wood, and the mucous membrane of the stomach occasionally has a blackened appearance, owing to the presence of altered blood Occasionally the lining membrane of the stomach and duodenum are reddened. The antidotes are Chalk and Magnesia, or its carbonates, mixed with water.
In Inflammation of the Mucous Mrmbranes of the Lungs and Stomach, M. Nardo,* of Turin, states that for above twelve years he employed this acid with uniform success. He administered one decigramme (about gr. iss.), in solution, daily. In these doses he found it to possess powerful antiphlogistic properties, and to act as a direct sedative. He advises the following formula: - ℞ Mucilag. Acac. fiij., Acid. Oxalic, gr. iss. - gr. ij., Syrup, fj., M., sumat. coch. min. pro dos Dr. Hastings mentions some cases of Phthisis in which Oxalic Acid in 1/2 gr. doses (alternated with Fluoric Acid) appeared to exercise a beneficial influence.
* Garrod, Ess. Mat. Med., p. 327 On Stomach and Renal Diseases, p. 17. buy's Med. Jurisprudence.