In the hemorrhages, sulphuric acid is occasionally useful; but it docs not stand among the most efficient remedies. In hemorrhage from the stomach and bowels it may do good by a direct action on the bleeding surface; but even here it has found no great favour with the profession generally. In that from surfaces which it cannot directly reach, as in haemoptysis, haematuria, monorrhagia, etc., its efficacy has been doubted, upon the ground that it does not come in contact with the bleeding vessels; but it is probable, as before explained, that the saline compounds which it forms in the alimentary canal may enter the circulation, and these salts may be as styptic as the acid itself. Nevertheless, sulphuric acid has no sufficient haemostatic power to be relied on exclusively in the treatment of the hemorrhages, and, for the most part, is employed merely as an adjuvant. The incompatibility between it and acetate of lead would forbid its use, in any case, in conjunction with the latter remedy.

In colliquative sweats, there are few remedies more efficacious than sulphuric acid. Its use in cases of this kind attending convalescence, the hectic of phthisis and scrofula, and the suppurative stage of inflammation, has been already referred to. But whenever excessive sweating occurs, especially if during sleep, and with general debility, as happens sometimes idiopathically, and often in connection with other diseases, the remedy may be resorted to with a reasonable hope of benefit. Generally, in such cases, it may be advantageously associated with sulphate of quinia. It probably acts either through the astringency of such of its salts as enter the circulation, or, what seems to me more probable, by a sympathetic propagation of its action on the bowels, through the nerve centres, to the surface of the body.

From its supposed possession of refrigerant properties, it has been recommended in fevers generally; but I have never seen it useful in cases where the prominent indication was to reduce the pulse and heat of the body; and I have, therefore, much doubt as to the existence of any property of this kind, at least in a sufficient degree to justify its use upon that ground alone. The saline compounds which it forms in the primae viae may, when absorbed, prove somewhat refrigerant, as the neutral alkaline salts generally are known to do; but if such an effect is produced in fevers, it is more than counterbalanced by the tendency of the acid to disturb the stomach, already but too prone to irritation.

The phosphatic lithiasis, or that condition of the system, and of the urinary organs, in which there is a disposition to an excessive formation and deposition in the urine of the earthy phosphates, is often treated with the mineral acids; and, among them, with the sulphuric. One object in the treatment of this affection is to maintain a due acidity of the urine, by which the phosphates are held in solution; and another, to give tone to the digestive organs, which are often in fault. Now, it was supposed that these objects would be accomplished by acid medicines, possessing, like the one in question, tonic powers; the supposition being entertained that the acid would pass out through the kidneys, and thus impregnate the urine. But the mineral acids arc not absorbed as such; neither are they thrown off as such by the emunctories. As before stated, it is in the form of salts that they enter the circulation, and are eliminated. Nevertheless, experience has proved them to be among our best remedies, if not the best, in this affection; and, though they do not directly acidify the urine, it is very possible that they may do so indirectly. In the contents of the bowels, and in the blood, are salts, from which the acid matter normally contained in the urine is probably separated. The sulphuric acid introduced into the stomach must, in order to form salts, decompose some saline substance which it meets with in the primae viae: and the liberated acid may either be absorbed, and escape with the urine, or, in its turn, disengage from some one of the salts of the blood an acid to be thrown off by the kidneys.

Sulphuric acid had at one time some reputation as a remedy in colica pictonum, and is still considered a good prophylactic, against that complaint, under certain circumstances. It was supposed to act by forming an insoluble and inert salt with the lead, and thus to remove the cause of the disease. But the preparations of lead do not produce colica pictonum, while lying loose in the alimentary canal, or even precipitated upon its surface. They must enter the circulation, and come into direct contact with the nervous tissue which they affect. Now, sulphuric acid cannot follow them into the circulation and the tissues; and, even if, in the form of soluble sulphates, it should do so, the formation of an insoluble compound of lead in these situations, from which it could not be readily removed, would not, it appears to me, be the best method of expelling the poison. So far as the acid can do good by combining with any lead in the stomach and bowels, thus far it may be useful in colicapicto-num, by preventing the further absorption of the poison. It may, therefore, prove prophylactic, if habitually used as a drink by those who are exposed to the necessity of swallowing small quantities of lead with their saliva, or antidotal in those who may accidentally take the poison into the stomach in larger quantities; but all that it could do chemically in such cases, could be as well done, and with less liability to injury, by the use of one of the soluble sulphates. It must, therefore, act by some other than its mere chemical properties, if it has any special usefulness in the poison of lead; but that it has such usefulness, remains yet to be satisfactorily proved.

Dr. D. Darrach, of Quincy, Illinois, has found this acid, in several cases, very efficient in the expulsion of tape-worm. He used it in the form of the aromatic sulphuric acid or elixir of vitriol, of which he gave a drachm, diluted with several ounces of water, in the course of three or four hours. (Am. J. of Med. Sci., Oct. 1860, p. 378).

The acid has been used externally in eruptive affections, as lichen, prurigo, obstinate urticaria, and psora, and in indolent or ill-conditioned ulcers. It is also employed as a gargle in ulcerated sore-throat, and the anginose affection of scarlatina, and as a caustic application to diphtheric exudation in the mouth and fauces. But for all these purposes, its place has been supplied by more efficient or more convenient remedies: and it is now little employed. When used, it should be much diluted. The precise strength will be mentioned under the preparations.

Incompatibles. If the special action of sulphuric acid is wanted, it should not be given with metallic iron; with salifiable bases, with which it forms salts; with the carbonates, or salts of vegetable acids; with soluble nitrates, chlorides, iodides, or sulphurets; or with the soluble salts of lime, baryta, and lead, which it decomposes, forming insoluble or nearly insoluble sulphates of these bases respectively. Sometimes, possibly, it may be appropriately administered in connection with one or more of these substances; but this should never be done, unless with a view to the reactions which must follow.