Amongst the many schemes which have been proposed to secure the public against the possibility of mistaking this acid for Epsom salts, there does not appear to be one which admits of successful application; nor are we able to propose any test of discrimination which is not far inferior in accuracy and convenience, to that which is afforded by the mere taste of the crystal; indeed we cannot understand how so acid a solution can be swallowed, without an immediate discovery. _Symptoms of Poisoning by Oxalic Acid._ From the history of the many cases on record, it appears that this acid produces all the grievous symptoms, which characterise the action of a corrosive poison; its operation upon the stomach is similar to that of any other powerful acid; and dissection displays the same destruction of parts, as that we have already described under the consideration of the mineral acids. _Antidotes._ We should endeavour to form as quickly as possible an insoluble oxalate of lime; copious draughts of lime water, or magnesia and water, should be administered; and vomiting immediately excited. _Chemical tests for the detection of Oxalic Acid._ If any of its crystals can be obtained, we shall be immediately able to identify them. They dissolve very readily in water, and since the oxalic has a greater affinity for lime, than any other acid, and forms an insoluble salt with it, we have thus a ready test of its presence, for it will decompose all the calcareous salts, not even excepting the sulphate. BOILING WATER.