This treatment of malignant tumours by electrolysis is yet _sub judice_, but the evidence in its favour has recently much accumulated, and its full and exhaustive trial by competent observers possessing the opportunities of large hospital practice ought not to be much longer delayed. [SN: Electrolysis of Malignant Tumours.] Neftel, of New York, who is its chief advocate, contends that malignant tumours are at first entirely local, and he explains their recurrence, after removal by the knife, from the fact of the impossibility of the whole of the diseased mass being excised, as apparently healthy parts when microscopically examined show that they have already become infected. Electrolysis he considers acts not only on the tumour but also on the surrounding tissues, the current being diffused to some distance in all directions. After electrolysis he applies a mild and not painful current for from a quarter to half an hour daily to the _locus morbi_, and continues this for some months. In one of his cases a mammary tumour existed of the size of a small orange. Three needles, from the negative pole of thirty-five cells, were inserted for half an hour under chloroform, and the operation was repeated thrice at intervals of a week, daily external galvanization being also used. The tumour gradually became smaller, and at last disappeared, but external treatment was continued for several months. At the end of a year there had been no relapse. In another case, in which the tumour had been excised by Marion Sims, it reappeared, and was again removed by the same surgeon, and pronounced cancerous. It again reappeared and was then electrolyzed, upon three occasions, by two, three, and four needles respectively, and with a current gradually increased from ten to thirty cells. The tumour by degrees grew less, and in three months was entirely dispersed; while, when the patient died from another disease three years afterwards, there had been no recurrence. [SN: Aneurismal Electro-puncture.]