Oxalic acid is never used in medicine, but, as a poison, it has caused accidental death so often that it will be included here. There are two forms of oxalic acid: one, the simple acid, which is found in sorrel and several other vegetable substances; the other, the article known as essential salt of lemon, one of the most violent of the corrosive poisons, and often mistaken for Epsom salt.

Symptoms Of Poisoning

A hot, acrid taste, and burning in the throat and stomach; intense abdominal pain, and vomiting of greenish, brown, or bloody mucus of very acid reaction; livid, cold skin; small, irregular pulse; unconsciousness, stupor, and collapse. In some cases the gastric symptoms predominate, in others the nervous symptoms, as convulsions, numbness, paralysis, and stupor.

The smallest fatal dose known is ʒ i. An ounce usually proves fatal, and the symptoms appear immediately. Death may occur within a few minutes, or may be delayed more than a week, and then take place from starvation resulting from the injuries to the intestinal canal.

Treatment Of Poisoning

The immediate administration of an antidote is of the greatest importance. Neither potash nor soda can be used, as their oxalates are poisonous; but lime and chalk are perfect antidotes, and can be given as precipitated chalk or saccharated solution of lime, or they may be scraped off the wall, whitewashed fences, or ceilings, stirred up in milk, and freely administered. Emetics, followed by the soothing and demulcent drinks usual in the after-treatment of irritant poisons, are employed, and stimulants, with external warmth.

Dr. Potter says that the stomach pump should never be used in cases of oxalic acid poisoning.

The use of oxalic acid with permanganate of potash in the surgical theatre as a part of the process of hand and finger-nail disinfection for the surgeon is dealt with in text-books on operating-room technique.