The chloride of zinc was first introduced as a secret remedy for cancer by Canquoin in Paris in 1837, and was combined with sanguinaria in the paste of Dr. Fell, which had a temporary popularity (Medical Times, i., 1858, p. 11). Veiel recorded excellent results from its use in lupus (Medico-Chirurgical Review, ii., 1860), and it is certainly a very reliable escharotic. I have seen immediate improvement from it, in some very severe cases, especially of facial lupus and rodent ulcer. It has disadvantages in being deliquescent, and hence readily penetrating adjacent healthy tissues and disposing to hemorrhage, but when mixed with flour, zinc oxides, or better still with lime sulphate or gutta-percha, it becomes quite manageable. The nitrate of zinc, though not in such frequent use, has, perhaps, advantages over the chloride; according to Mr. Marshall, it penetrates deeper, and causes less pain: in lupus it was commended by Dr. Tilbury Fox, and I have had very successful results with it, generally using a paste made with equal parts of nitrate, flour, and mucilage spread on lint.

Both this salt and the chloride are equally applicable to all forms of strumous and syphilitic ulceration. Franchi reports arrest in some very severe cases of this kind, when acid nitrate of mercury, iodine, etc., had been tried, without success (Gazette Med. de Paris, February, 1870). Maisonneuve used the chloride made into firm paste with flour in the form of fleches ("arrowheads"), which he thrust into incisions all round a morbid growth, thus destroying a zone of tissue and separating the tumor; but this process is more painful and prolonged than the use of the knife, and does not prevent recurrence better than an equally extensive incision.

Sir J. Y. Simpson advocated sulphate of zinc in powder as the best caustic for these maladies, whether affecting the uterus or other parts: it is simple, easily applied and managed, safe, efficient, fairly rapid in action (five or six days), and does not deliquesce. In cases where the epithelium was destroyed, he applied the anhydrous salt in fine powder or mixed with glycerin into a paste (1 oz. of sulphate to 1 dr. of glycerin). In other cases, e.g., of cancer of the breast, he mixed the salt with sulphuric acid and scored the part with a quill at successive applications (Medical Times, i., 1857, and 1859); he records many good results, which were to some extent corroborated, but his practice has not been largely followed. Mr. Erichsen found it very painful (Medical Times, i., 1857, p. 238).