Its taste is highly acid and caustic. So powerful is its affinity for water, that upon its admixture with this fluid, a heat, sufficiently great to boil water, may be produced. When exposed in its concentrated state to the air, it will imbibe at least seven times its own weight of water, and so rapidly as to have its weight doubled in a month. Straw, wood, and all vegetable substances, when immersed in the sulphuric acid, without heat, are disorganized, softened, and blackened, and there is separated from them a certain portion of charcoal. Like the other mineral acids, the _Oil of Vitriol_ has never been obtained in an insulated state without water; according to the latest views of _Sir H. Davy_, the composition of the strongest acid may be expressed as follows. Sulphur 30, oxygen 45, water 17. _Symptoms of Poisoning by Oil of Vitriol._ An extremely austere, acid, and burning taste; a painful heat in the fauces and throat, along the œsophagus, and in the stomach; excruciating pain; nausea, and excessive vomiting; at one time the fluid vomited is as black as ink, at another reddened by arterial or venous blood, producing in its passage through the throat, the most intense pain, accompanied with a sensation of bitterness quite intolerable; if, by chance, a portion of it should fall on the hearth or pavement, or on any other calcareous substance, it will denote its true nature by an effervescence; constipation, or sometimes bloody stools; gripes and excruciating pains over the abdomen, with a tenderness of these regions, so exquisite as not to allow the slightest pressure without torment; pains of the breast; difficulty of breathing; extreme anxiety; the pulse becomes frequent, small, contracted, and irregular; shiverings; great restlessness, dejection, and agitation; convulsive motions of the countenance; sometimes a cutaneous eruption betrays itself. Amidst all these symptoms, the intellectual powers remain unobscured. The parts about the fauces, the uvula, &c. having lost their vitality, slough, and become detached, which occasion an indescribable fetor of the breath, while they produce a perpetual cough, and the voice becomes so altered, that it resembles the sounds of a person labouring under croup. _Organic lesions discovered on Dissection._ As this substance destroys life by simply acting as an escharotic, it is not difficult to anticipate the disorganization which dissection will display. The extent of the lesion, however, must in every case depend upon the quantity and degree of concentration of the acid, the state of the stomach in relation to its alimentary contents, and other incidental circumstances not to be exactly appreciated. The mucous membrane of the mouth, the tongue, and œsophagus, will in general be found destroyed, and converted into a pulp. _Antidotes._