Its power is universally admitted, both by English and Continental surgeons. It is often esteemed a specific. Among others, Mr. Hunt, in a treatise on Syphilitic eruptions, maintains that Syphilis has a tendency to go on without limit if left alone, but that Mercury in sufficient doses possesses the power of totally destroying the poison, and preventing its transmission. Mr. Carmichael was of opinion that Mercury was only applicable in those cases which exhibited the true Hunterian chancre, round, cup-like, and hard, followed by a leprous eruption. But it is more in accordance with common experience to say that the only contra-indications to the use of Mercury in primary Syphilis are these--a scrofulous or very debilitated state of the system; and a sloughing or irregular appearance of the primary sore. We may administer Mercury in two forms. It may be given as Calomel or Blue pill, with or without Opium, and continued until it affects the mouth. Or the Bichloride may be administered in minute doses, and may prove efficacious without producing salivation. It should be commenced as early as possible; and in most cases the action of Mercury in the blood, of whatever nature that action may be, will meet and neutralize the advance of the syphilitic virus, preventing its further manifestation in a secondary form. It is rarely necessary to push its action beyond the first symptom of salivation; for that will be evidence that the system is sufficiently saturated with it. Beneficial as it often proves when administered thus cautiously, yet, if given in excess, or to individuals that are over-susceptible of its action, it is capable of proving a poison every whit as noxious as the Syphilis which it was intended to neutralize. The mercurial cachexy is quite as deplorable, and quite as incurable as the Syphilitic cachexy. The Terchloride of Gold may be used in Syphilis in the same way as the Bichloride of Mercury; but it is much more seldom employed. There seems to be a strong medicinal as well as chemical similarity between these two metals and their compounds. Even the insoluble metal itself was used some time ago as an Antisyphilitic, apparently with success. In 1715, Dr. A. Pitcairn recommended finely-powered Gold as even more efficacious than Mercury in the treatment of Syphilis.