The best form for this purpose has been much discussed; Lewin, one of the first to recommend it, used 5 milligr. of corrosive sublimate, but this is too much. Dr. Walker gave 1/30 gr. in 10 minims of water and glycerin, and obtained good results in secondary syphilis without serious drawback, but Stohr, Greenfield, and others have reported local irritation, abscess, and even gangrene without therapeutical advantage. Liegeois added a minute quantity of morphia, but Staub's solution of albuminate of mercury secured more general approval. It is prepared with two separate solutions, thus: Corrosive sublimate, 1.25 gr.; chloride of ammonium, 1.25 gr.; chloride of sodium, 4.15 gr.; distilled water, 60 gr.: dissolve and filter. The second solution is made with the white of an egg very thoroughly agitated with 60 grammes of distilled water and filtered; the two liquids are then intimately mixed, and directed to be kept from the air as much as possible. The solution should, in fact, be prepared fresh as required, for it will not keep. One gramme contains 1 milligr. of the salt, and the dose should be about 1 centigr. daily at two injections. M. Bouilhon has recommended a solution containing a double iodide of mercury and sodium (Practitioner, 1869), and Scarenzi and Recordi the injection of calomel suspended in gum (Practitioner, 1870).

Stern's injection is made with 2 parts of sublimate and 20 of salt to 1,000 of water, and this does not precipitate albumen, and is a good form (Lancet, i., 1871), but Mr. Cullingworth, after many experiments, obtained by far the best of results with a minimum of local irritation by a solution of bicyanide, using 2 gr. with 1/2 oz. glycerin and 4 oz. of distilled water (10 min. = 1/16 gr.) - 1/2 gr. made the gums tender (Lancet, i., 1874). Duncan, of Edinburgh, reports good results from the same (British Medical Journal, ii., 1874).

The advantages of the hypodermic method are facility of dosage and rapidity of effect, cleanliness, and freedom from gastric irritation, yet the unpleasant results which have sometimes attended it have quite prevented its general adoption.

The Mercurial Vapor Bath is the best method of application for some cases especially of syphilitic cutaneous disease. In it calomel or sulphide of mercury is vaporized in conjunction with steam, and becomes deposited as finely divided powder on the body of the patient, as he is seated unclothed over the lamp. Care should be taken that the vapor be not inhaled, or profuse salivation may occur.