HO,MO,C40., and 31I0,M0,2C406, the last being a compound of the acid salt and the acid. Oxalate of lime 4Aq) and ordinary (neutral) oxalate of ammonia 2Aq) are examples of the first; binoxalate of potash, or, salt of sorrel (KO,I10,C40. 2Aq). is an example of the second; while the salt usually termed quadroxalate of potash 4Aq) is an example of time third class. Of the numerous oxalates, the most important are the oxalate of lime (in consequence of its physiological and pathological relations); the neutral oxalate of ammonia, which is the best test for the detection of lime in solu tion (in consequence of the extreme insolubility of oxalate of lime); and the acid oxalate of potash, which is contained in the juices of oxalis and rumex, and is em ployed in various manufacturing processes.
The best test for this acid is the production of a white precipitate (of oxalate of lime), omm the addition of any soluble salt of calcium. The precipitate is insoluble in water, in solution of potash, and in acetic acid, but dissolves in the mineral acids. A solution of nitrate of silver also gives a white precipitate of oxalate of silver, which explodes when heated.
In consequence of its employment in cotton printing, bleaching straw, etc., oxalic acid is more accessible to the general public than many other poisons, and on this account instances of suicide from the swallowing of this acid are by no means uncom mon. Cases of accidental poisoning, moreover, sometimes occur by its being sold by
mistake for Epsom salts. Large doses destroy life very rapidly. Dr. A. Taylor men tions a case in which a man died in 20 minutes after taking 2 oz. of the acid. Dr: Cbristison records a case in which an ounce killed a girl in 30 minutes, and another case in which the same quantity destroyed life in ten minutes; and, as a general rule (liable to exceptions), when time close is half an ounce or upward, death commonly takes place within the hour. The symptoms are a hot or burning acid taste, with a sense of con striction or suffocation; vomiting• great pain in the region of the stomach, convulsions, cold perspirations and general collapse speedily follow; and respiration shortly before death becomes slow and spasmodic. With the view of converting the free acid in the stomach into an insoluble and inert salt, chalk, whiting, or lime-water, with full draughts of milk, shoula be administered with the least possible delay. Salt of sorrel is almost as poisonous as the pure acid.