Abstract 1. 1. Urinary excretion of total metanephrine and normetanephrine was significantly lower in 20 cases of rheumatic fever and relative “collagen diseases”, as compared to 10 normal control cases. 2. 2. Ingestion of l-tryptophan resulted, in 2 out of 3 normal children, in significant increase of the urinary excretion of these compounds ; m 4 out of 6 patients it resulted in significant decrease. The difference between the groups was statistically significant. 3. 3. Synthetic vanilpyruvic acid produced a number of degradation products when its solutions in ether or ethyl acetate were stored in the freezer without exclusion of oxygen, or when freshly prepared solutions were subjected to paper chromatography with an alkaline solvent system. Besides vanillin and homovanillic acid, a substance, accounting for the largest percentage of the degradation products, coincided on the chromatograms with the spot of vanillactic acid.