The great indications to be fulfilled in this distressing case, is the immediate dilution, saturation, and expulsion of the poison. Copious draughts of water, holding calcined[321] magnesia in suspension, should be administered without any loss of time. If this is not in readiness, soap and water should be administered; mucilaginous drinks, milk, and even warm or cold water, in the absence of more eligible potations, should not be neglected. It must be never forgotten, exclaims _Orfila_, that success upon these occasions depends upon the activity of the practitioner; the delay of a few moments will entirely change the fate of the patient, as the sulphuric acid destroys the texture of the organs with a fearful celerity. After having thus neutralized the caustic, it will be our duty to obviate the effects it may be likely to occasion; the lancet must be used with boldness, and the detraction of blood repeated at short intervals; at the same time emollient clysters may be advantageously injected. _Chemical processes for the detection of Oil of Vitriol._ In the pure state, there can exist no difficulty in identifying it; its specific gravity, and its action on vegetable matter, will, without any other tests, be quite sufficient to fulfil our object. If heated with metallic mercury, it will disengage sulphurous acid gas; and if united with lime, a sulphate of lime will be produced, which the chemist may easily recognise by dissolving a portion in distilled water, and assaying the solution by _muriate of baryta_, which will produce with the sulphate a precipitate, insoluble in nitric acid. By the last mentioned tests we shall be enabled to detect the presence of sulphuric acid, in whatever state of complication it may happen to exist with alimentary matter. NITRIC ACID. This acid, when pure, assumes the form of a limpid fluid, emitting white fumes of a suffocating odour; its taste is highly acid, and corrosive; and it is at once distinguished from all other acids, by its tinging the skin indelibly yellow. When of the specific gravity 1·5 it contains 74·895 per cent of dry acid, (whose ultimate elements are one proportional of nitrogen, and five of oxygen) the complement 25·105 parts, is water.[322] It is decomposed with violent action by all combustibles, and when mixed with volatile oils it causes their inflammation. From the facility with which this acid undergoes decomposition, it is rarely found in commerce in a colourless condition; indeed the action of light is sufficient to impart a tawny tinge to it; when this change has proceeded to such an extent as to render the acid orange coloured, it is called _Nitrous acid_, or, in the language of the arts, _aqua fortis_, although in a chemical point of view, such a nomenclature is incorrect, for it is nothing more than nitric acid, holding nitrous acid gas loosely combined. _Symptoms of Poisoning by Nitric Acid._