Mr. Mayo¶ applied Potassa Fusa over the trunks of the subcutaneous veins of the leg, affected with varix, in order to produce inflammation of the vein, with coagulation of the blood in it, and obliteration of the cavity. In some few instances, he observes, on the healing of the ulcer left by the separation of the eschar, no effect on the vein was observable; but in much the greater proportion, the vein became firm and hard, and its cavity was obliterated at the part where the issue had been made. He adds that he never witnessed phlebitis supervene, in following this practice. It is, however, rarely employed at present. The practice is not unattended with danger.

2169. In Eczema, solutions of Caustic Potash have been recommended as external applications by Hebra and Dr. T. M'Call Anderson.** The latter recommends that in the mildest cases, with only slight infiltration, gr. ij. of Potassa Fusa in Aq. fl. oz. j. be applied; but in more severe cases the strength of the solution may be increased to 5, 10, 20, or even 30 grains or more to the ounce. The solution should be applied with a broad brush, and should be washed off speedily with water. The stronger solutions should not be applied more than once a day. If it produce any manifest destruction of the skin, it has been applied of too great a strength, or been allowed to remain too long. In very obstinate cases, and where the eruption is very limited, Hebra sometimes uses a solution of gr. lx. of the Caustic Potash to Aq. fl. drs. ij., or even applies the solid caustic itself. This must be done, however, with the greatest circumspection, and the caustic must be washed off immediately.

* Lancet, July 15 and Aug. 5,1854. Med.-Chir. Trans., vol. ix. X Synopsis of Diseases of the Skin, p. 330.

§ Dub. Quart. Journ., Feb. 1851. || Archiv. Gen. de Med, April,

¶ Outlines of Human Pathology, p. 443.

** Med. Times and Gaz., July 11, 1863.