In 1944 Albanese, Frankston and Irby1 published their hydrogen peroxide – perchloric acid oxidation method for the estimation of methionine in protein hydrolysates and human urine. They stated: “… the applicability of the procedure to the urine was established by means of a study which demonstrated that the normal urinary constituents failed to react as methionine. This practice was further justified by the observations that the ingestion of dl-methionine by normal individuals resulted in a prompt elevation of the methionine level in the urine, as determined by our method. From a limited series of observations, it has been found that the normal adult (male) on a normal diet excretes 247 to 494 mgm. of methionine daily.”