This investigation was undertaken to study the toxicity of novasurol (merbaphen) by observing the lesions produced in the kidney of the rabbit following intravenous injection. Novasurol is an organic compound containing 33.9 per cent of mercury. It is the double sodium salt of oxymercuric orthochlorphenyloxy acetate and dimethylmalonyl urea, and it is prepared for use as a 10 per cent neutral sterile solution. It was first introduced by Bayer and Company as an antisyphilitic agent. Zeiler,1 in 1917, was the first to describe its therapeutic use in this disease.
Soon after its introduction it was observed to have a marked dieuretic effect, especially in those cases in which edema had developed. The fact that small doses of mercuric compounds produce a diuresis is not new. As early as 1800, it was known that the diuretic action of digitalis is enhanced when given in conjunction with mild mercuric chloride. This fact