Fatal Period.—Death has occurred in three minutes; also delayed to sixty hours; usually three to four hours.
Fatal Dose.—One drachm has caused death in twelve hours. A child six months old died from the effects of a quarter of a teaspoonful of a solution of one part of the acid to five of glycerine. Recovery has taken place after an ounce of 90 per cent. strength liquefied acid, also after four ounces of the crude acid; after six ounces of the crude acid, 14 per cent. strength; and in a child of two after half an ounce of crude acid of 30 per cent. strength.
Treatment.—Stomach pump. Wash out the stomach with equal quantities of alcohol and water mixed—whisky, brandy, gin, or rum will do until absolute alcohol or rectified spirit be obtained. The washing should be repeated every 5 to 15 minutes from four to eight times; apomorphine hydrochlorate gr. ⅒ should be given hypodermically at the commencement, and the administration of demulcent drinks. Emetics are of little or no use, owing to the anæsthesia of the mucous membrane of the stomach. The sulphate of soda, Glauber salts, has been proposed as an antidote. Any soluble sulphate may be tried. Oil or vinegar is the best outward application to the skin, after washing with spirit of wine or methylated spirits.
OXALIC ACID
This is a powerful corrosive and cardiac poison, but on account of its strongly acid taste it is ill-adapted for the purposes of the murderer. Deaths have not infrequently followed the accidental substitution of this substance for Epsom salts—sulphate of magnesia—which it somewhat closely resembles.
The ordinary crystals of oxalic acid are in the form of four-sided prisms, colourless, transparent, odourless, or with a slight acid smell, very acid taste, and not deliquescent in the air. It is largely used in the arts, by brass-polishers, straw-bonnet makers, book-binders, and others. The acid is also used to remove writing-ink from parchment, paper, &c., for the purposes of forgery, &c.
Symptoms.—These present many strange anomalies. In a large dose—an ounce or more—oxalic acid acts as a corrosive; in a smaller, as an irritant; and in a still smaller dose, as a cardiac sedative. Death has been known to occur so rapidly as to prevent any attempt at treatment. When the dose is large, an acid taste is experienced during swallowing, followed by burning pain in the throat and stomach. Vomiting then sets in, and in most cases continues till death, which may, however, occur when this symptom has existed from the first. The vomited matters may be simply mucus, mucus and blood, or dark coffee-grounds-looking matter. Unless the case is protracted, the bowels are rarely much affected, though purging and tenesmus have been noticed. Occult blood may be present in the fæces. Collapse now sets in; the pulse becomes feeble and scarcely perceptible, the skin cold and clammy, showing the action of the poison on the heart probably through the central nervous, as well as through the intra-cardiac ganglia. Should the treatment adopted prove successful, and life be prolonged, the patient complains of tenderness of the mouth, soreness of the throat, and painful deglutition. Pressure over the abdomen causes pain. Vomiting and purging are also frequently present; and if recovery takes place, convalescence is generally very gradual. The urine may contain a large quantity of albumen, casts are numerous, and oxalates in crystal form are present.
Fig. 28.—Photo-micrograph of crystals of oxalic acid, × 50.
(R. J. M. Buchanan.)
Oxalic acid acts as a poison when applied to a wound in any part of the body; and although this substance undoubtedly acts on the brain through the medium of the blood, it is a remarkable fact that it cannot be detected in that fluid, even when injected into the femoral vein of an animal which died in thirty seconds (Christison). Leeches, it is recorded, have been poisoned by the blood drawn by them from persons suffering from oxalic acid poisoning. The blood does not appear to undergo any physical change. Unlike the mineral acids, oxalic acid is still poisonous even when its corrosive and irritant properties have been destroyed by dilution.