Sulphuric acid was known as early as the seventh century. As found in commerce, it is often called oil of vitriol, and is more or less impure, containing, among other foreign bodies, a small proportion of sulphate of lead, which, however, is thrown down when the acid is diluted with water; so that practically its presence is of less importance than might have been supposed. For an account of the chemical properties and characteristics of this acid, the reader is referred to the U.S. Dispensa -tory. I shall here treat of its relations to the human system, and afterwards of its preparations; premising that the strong acid, though much employed as a pharmaceutical agent, and sometimes as a caustic, is never directly prescribed for internal use.

Effects on the System

When taken in very small doses, sufficiently diluted with water, sulphuric acid produces at first no other observable effect than to increase the appetite. But, after a short time, digestion and secondarily nutrition are found to have been promoted; and a tendency to constipation is sometimes evinced. It is said also somewhat to reduce the frequency and fulness of the pulse, and to diminish the temperature of the body, especially if previously elevated; though I cannot say that I have myself ever noticed these effects. Dr. Christison, in his Dispensatory, states that it is also diuretic, and that it sometimes succeeds in producing an increased secretion of urine in dropsical effusions, when other powerful diuretics have failed. "With these properties, sulphuric acid must be considered as tonic, astringent, refrigerant, and diuretic.

If given too freely, it produces uneasiness in the stomach, disturbance of digestion, griping pains in the bowels, and often purging; and the same effects may result from its too long continuance in proper medicinal doses. They are the direct consequence of its irritant action on the alimentary mucous membrane.

In large quantities, and even in smaller if taken in the concentrated state, as not very unfrequently happens by mistake, in consequence of the extensive use of the acid in the arts, it very quickly produces burning pain in the mouth, fauces, and stomach, with nausea and generally vomiting of bloody or dark coloured liquids, followed by excruciating pains in the bowels, sometimes attended with constipation, sometimes with purging and bloody stools. Occasionally there are spasms of the muscles of the face, back, and upper extremities, arising no doubt sympathetically, through irritation of the nervous centres. The voice often becomes hoarse from inflammation of the glottis; the breath sometimes fetid from the decomposition of the destroyed tissues; and generally, when a corrosive effect has been produced, great prostration comes on, with a cold surface, feeble and irregular pulse, intense anxiety, and in-cessant jactitation, which soon end in death; the mind remaining unclouded not unfrequently even to the very last. The fatal result sometimes takes place in a few hours, but more frequently at a period varying from twelve hours to two or three days, and occasionally is much longer protracted. When the quantity has not been sufficient to cause immediate death, the case may run on for weeks or months, with frequent vomiting of membranous flakes, fetid breath, great disturbance of the general system, and gradual emaciation, under which the patient at length sinks. Sometimes the effects are confined to the mouth and fauces; complete deglutition having been prevented by the excessive irritation, or other cause; and great destruction or inflammation of these parts may ensue, from which the patient may or may not recover. The appearances after death are those indicative of inflammation and disorganization of the mucous membrane. In some places, the surface is reddened by congestion; in others, whitened from a combination of the acid with the albumen of the tissue; and in others again, blackened by its decomposing effect, the blood being coagulated in the surrounding vessels Death results from the direct action of the acid on the alimentary mucous membrane, and probably in no degree through its absorption into the blood-vessels. Dr. Christison states that the smallest fatal dose of sulphuric acid which he had found recorded was a drachm, or somewhat more than half a teaspoonful. Patients, however, not unfre-quently survive the effects of much larger quantities. A case of recovery is recorded after six drachms had been swallowed; but such a result must be very rare, and could probably occur only in consequence of a prompt evacuation or neutralization of the poison. From a few drachms of the dilute officinal preparation of the acid, recovery may be reasonably hoped for, if prompt measures of relief are applied, or the immediate occurrence of vomiting has caused nearly all the poison to be thrown off. A patient got well after taking ten drachms of the aromatic sulphuric acid, or elixir of vitriol, which had brought on vomiting and purging of blood. (Lond. Med. Gaz., xxv. 944).

The treatment of poisoning by sulphuric acid consists in the prompt exhibition of substances fitted to neutralize the acid, with diluent drinks to favour the complete washing out of the stomach, and afterwards in the use of measures calculated to allay the inflammation, and support the patient, if necessary, until the recuperative processes shall have completed. The best antidotes are magnesia, chalk, and the bicarbonate of potassa and soda; but, in the absence of these, any salifiable base which may happen to be nearest should be at once resorted to, as soap, whiting, or even wood ashes mixed with water. The inflammation may be treated with demulcent drinks, and the ordinary antiphlogistic measures, carefully graduated to the amount of reaction, and the probable future strength of the patient. Where the stomach rejects everything, attempts should be made to support the system by animal broths injected into the rectum.