Administration to a single subject under as far as possible corresponding conditions of a series of simple saturated triglycerides leads to urinary excretion of dicarboxylic acid in very different amts. Triglycerides derived from acids with odd and even nos. of C atoms do not differ in w-oxidation of the component fatty acids. The excretion of dicarboxylic acid is largest with triundecylin and tricaprin; it diminishes on descending the series. No dicarboxylic acid is excreted after administration of the higher triglycerides. Some serial change must exist in the ketogenic properties of successive triglycerides derived from fatty acids with even nos. of C atoms.