Oxalic acid is one of the poisons alluded to under the head of General Poisoning,—of whose operation distinct evidence may sometimes (though certainly not always) be found in the symptoms. If a person, immediately after swallowing a solution of a crystalline salt, which tasted purely and strongly acid, is attacked with burning in the throat, then with burning in the stomach, vomiting particularly of bloody matter, imperceptible pulse and excessive languor, and dies in half an hour, or still more in twenty, fifteen, or ten minutes, I do not know any fallacy which can interfere with the conclusion, that oxalic acid was the cause of death. No parallel disease begins so abruptly and terminates so soon; and no other crystalline poison has the same effects.
Poisoning with the Oxalates.—Oxalic acid is one of the best examples of a poison that acts through all its soluble chemical combinations. Dr. Coindet and I found that the oxalates of potash and ammonia are little inferior in energy to the acid. They do not corrode, indeed, and scarcely ever irritate; but they produce tetanus and coma, like the diluted acid. Half a drachm of oxalic acid neutralized with potass will kill a rabbit in seventeen minutes; ninety grains of neutral oxalate of ammonia will kill a strong cat in nine minutes.[[423]] The binoxalate of potash, the most familiar of the salts of oxalic acid, was not tried by us. But the preceding facts would leave little doubt of its being a poison.
Since the last edition of this work was published several cases have occurred which amply confirm the results of experimental inquiry. In Dr. Babington’s case alluded to above, the greater part of the oxalic acid had been neutralized by bicarbonate of soda [p. [176]].—Mr. Tripier has communicated the particulars of a case in which half an ounce of the binoxalate of potash was taken by mistake for bitartrate of potash in hot water, and caused death in eight minutes, after an attack of violent pain and convulsions.[[424]]—A young woman at Bordeaux was attacked with frequent vomiting after a dose of a drachm and a half of the same salt dissolved in a ptisane. Next morning a similar dose caused bloody vomiting and acute pain at the pit of the stomach; and a third dose the following day excited delirium, more violent vomiting, and death in the course of an hour.[[425]]—A girl in London swallowed about an ounce of the same salt dissolved in hot water. Sickness and faintness ensued, with imperceptible pulse, cold, clammy skin, rigors, scalding of the mouth and throat, pain in the back, soreness of the eyes, redness of the conjunctivæ, and dilatation of the pupils. Afterwards there was reaction, with a full frequent pulse, hot skin, flushed countenance, headache, thirst, and tenderness of the abdomen. She recovered under the use of chalk, external heat, ether and opium draughts, leeches and sinapisms to the belly, and carbonate of ammonia.[[426]]
No account has yet been published of the morbid appearances in man.
The proper antidote is sulphate of magnesia. Failing this, weak milk of lime may be given with advantage.
Appendix on Tartaric and Citric Acid.—These two acids may be taken in considerable quantities without injury. Dr. Coindet and I gave a drachm of each in solution to cats, without observing that the animals suffered any inconvenience.[[427]] Dr. Sibbald, a surgeon of this place, has informed me of an instance in which a patient of his took in twenty-four hours six drachms of tartaric acid, having by mistake omitted the carbonate of potass sent along with the acid to make effervescing draughts; and yet he did not suffer any more inconvenience then the cats on which Dr. Coindet and I experimented.
Pommer, however, found that tartaric acid is scarcely less active than oxalic acid when injected into the blood. When fifteen grains dissolved in half an ounce of water were injected into the femoral vein of a dog in four doses, difficult breathing and discharge of fæces and urine were produced after each operation, and death speedily ensued without any other particular symptom. As in the instance of oxalic acid, the blood in the great veins was not apparently changed in any of its physical qualities. The heart continued contractile long after death, while in the case of oxalic acid its contractility was suddenly extinguished.[[428]]
CHAPTER VII.
OF THE ALKALIS AND ALKALINE SALTS.
The second order of the class of irritants comprehends the alkalis, some of the alkaline salts, and lime. The species which it includes are little allied to one another except in chemical composition; and in particular they are little allied in physiological properties. It appears impossible, however, to make a better arrangement than that proposed by Orfila, which will therefore be here followed.
Most of the poisons of the second order are powerful local irritants. Some of them likewise act indirectly on distant organs; and a few are more distinguished by their remote than by their local effects. This order may be conveniently divided into two groups,—the one embracing the two fixed alkalis with their carbonates, nitrates, and chlorides, and also lime,—the other ammonia, with its salts, and likewise the alkaline sulphurets.