MOLARITY VERSUS PER CENT
Abstract
Abstract To the Editor: In patch testing, the concentration of the active agent in the inert vehicle is often of critical importance. Per cent is the usual way of specifying concentration. In the case of metal salts, the use of per cent has led to a curious error. Surprisingly enough, the "5%" nickel sulfate solution used by many dermatologists contains only 3% nickel sulfate ! This error results from technicians simply weighing out 5 gm of the commercially available nickel sulfate...