The standardization of disinfectants has been one of the problems claiming the attention of workers in many laboratories. Some of these investigations have found their way into publications; many have not been reported. The comparative study of disinfectants has been of considerable importance, particularly when associated with chemical studies of different groups of bactericides in an attempt to elaborate new compounds effective as bactericides and nontoxic to the body tissues. Although a germicide which has been shown to be very effective under the conditions of a laboratory experiment may, for one reason or another, be unsuitable for clinical use, the laboratory findings in general provide a useful guide to its relative value.

The methods most used in determining the phenol coefficient are modifications of the Rideal-Walker method¹ proposed in 1903. It will be unnecessary to describe here either this method or its modifications as proposed by Anderson and McClintic,