Starch is extracted from a 50to 250-mg. sample of dried plant tissue with perchloric acid as recommended by Nielsen, precipitated with iodine, and recovered as starch which is hydrolyzed and determined as glucose. The results are independent of the composition of the starch of different species with respect to amylose and amylopectin. Theoretical recoveries of glucose from pure potato starch are obtained; the experimentally determined factor is 0.90 with an uncertainty of ±1.2%. The precision of the method as applied to a variety of plant tissues is approximately 2%.

ALTHOUGH glutamine has been known for many years to be a constituent of certain plant tissues [Schulze and Bosshard, 1883], no method whereby this substance can be separately distinguished from asparagine and determined with accuracy has appeared until recently. Glutamine has indeed frequently been isolated but its properties are such that isolation has only qualitative significance. Chibnall and Westall [1932] noted that the amide group ofglutamine is extensively hydrolysed by heating at 1000 for 3 hours at PH 8, whereas asparagine is scarcely affected by this treatment. Accordingly they suggested that the glutamine

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this leakage was due to the method of mounting the gears, and the figures are much higher than would be found in practice. However, the relative figures show what may be expected with gears in poor mechanical condition.To the management of the Shell Oil Company, the author wishes to express his appreciation for permission to publish the data contained in this paper. These investigations were made possible by the cooperative efforts of several co-workers acting under the supervision of A. G. Marshall, assistant superintendent of the Martinez Refinery. The author is grateful not only to Mr. Marshall for his advice in carrying out these tests, but to other members of the Shell Oil Company Motor Laboratory staff: