H2C204 plus 2H2O.
Oxalic acid, the acid of sorrel, was first discovered in the juice of the sheep-sorrel.
In the older works of homoeopathy all the acids were placed under the letter A; this arrangement is no longer followed and they are now placed in their proper alphabetical order.
Oxalic acid was first proved by Dr. Charles Neidhard, in 1844.
Oxalic acid causes violent gastro-intestinal inflammations, with irregular pulse, stupor and collapse, or convulsions. It paralyzes the motor centres of the spinal cord and causes apparent inflammation of the cord and its sheath.
The important symptom for us to remember under the remedy is that the pains occur in short areas, half an inch to one inch in length, last only a short time, but are very violent. The symptoms of the remedy usually intermit and then return in a diminished degree.
A condition that does not occupy a prominent place as yet under the remedy is that the symptoms re-appear as soon as he thinks of them (8).
We find pains in the joints as from rheumatic gout, especially worse from sweets (6).In reference to disordered stomachs, we have salivation (163), tasteless eructations, burning in the stomach and vomiting, but of more importance is gastralgia, with a feeling of coldness between the stomach and umbilicus (178).
In the diarrhoea of Oxalic acid the stools are profuse and watery, with frequent ineffectual urging, and worse from drinking coffee (57).
As regards the kidneys and urinary organs, our principal use for the remedy is in oxaluria (148), especially when associated with general gouty symptoms and exhaustion.
In the sexual organs, Oxalic acid is useful, in the male, for neuralgia of the spermatic cord (171), with terrible pains, worse from the slightest motion; in the female, we can think of it for amenorrhoea from taking cold (134) and associated with general asthenia.
In the heart we have palpitation, “heart in a continual flutter” (Hering), coming on after lying down at night (111). It is useful in angina pectoris (107) when we have numbness of the limbs and pain in the cardiac region, worse from the least motion. The pains are severe, like short stitches, confined to a small spot and lasting but a few seconds at a time, or we have a sharp pain in l. lung and heart, with forced expiration.
The impression that I have of the character of the pains of Oxalic acid is the sensation as if a nerve were grasped or lifted by a pair of tweezers and then the tweezers slipped.
In neuralgia of the spine and in spinal irritation (171) requiring Oxalic acid, we have numbness (146) and weakness in the body, back and limbs, with coldness (71) and loss of motion of the limbs. The pains are darting and lancinating, noticed especially in the lung and about the heart, with jerking inspiration and forced expiration, as if trying to relieve the intense pain by emptying the lung.
In locomotor ataxia (127) we have, either, violent pains shooting down the extremities, with dyspnoea and numbness, or pains confined to small spots and lasting only a few seconds. In all these conditions the attack recur with periodical remissions. I have used Oxalic acid 3rd.