Clinical Uses of 2,3-dimercaptopropanol (bal). Xi. the Treatment of Acute Mercury Poisoning by Bal.

The extensive investigations upon the mechanism by which arsenic poisons the protoplasm of cells (1, 2) and the discovery (1) that the di-thiol, 2,3-dimercaptopropanol or BAL (British AntiLewisite), possesses an avidity for Lewisite and trivalent arsenicals, thus sparing injury to the cells and their essential enzymes, led to the suggestion that the toxic action of other metals might be explained in a similar manner. Evidence is now at hand to show that the principles involved in the injurious effect produced by mercury and cadmiium are analogous to those ascribed to arsenic (1 to 3). It has, in addition, been amply demonstrated (4) that BAL is a highly effective antidote to acute mercury poisoning in rabbits and dogs. In order to obtain complete or even partial protection against the poisonous effect of mercury bichloride, BAL had to be administered shortly after the injection of mercury; but when the first intramuscular dose of BAL was given 5 minutes after the intravenous injection of an amount of mercury bichloride fatal to the control animals, all of the rabbits survived. If, on the other hand, an interval of 30 minutes had elapsed, only about % of the animals could be saved. In dogs, however, this interval could be prolonged, and when the lethal dose of mercury bichloride was given by mouth, BAL proved to be an effective antidote after the lapse of several hours. In one series of experiments, 3 of 5 dogs survived a lethal oral dose of mercury bichloride when the first intramuscular injection of BAL was made 5 hours later, followed by subsequent injections at 2 and 4 hours. From the information available it seemed desirable to test the efficacy of BAL in the treat-