Owing to the deficiency of lysine in zein, the hydrolysate of this protein was used as the main source of amino acids in the preparation of the medium for microbiological estimation of lysine using Lcuconostoc mcsentcroides P-60. as the test ing microorganisms. Suitable quantities of tryptophane, arginine, cystine, glycine and serine were used to supplement the medium.The maximum rate of acid production by the microorganism in this medium is much higher than that in the medium used by Horn et al for the same purpose. The latter medium shows a rapid increase of acid production up to 80 ?g lysine per innoculated test, while our new medium gives a continuous increase of acid production up to 120?g. Thus, the range in which the amino acid can be estimated in much extended.Parallel analysis was made on 25 food samples with our new medium as well as those published in the literature. In 11 cases, the agreement was within 10%; in 13 cases, the results obtained with' our new medium were about 10% higher; and in only 1 case, the new medium gave a lower result. These differences are not due to routine analytical error as repeated estimation gave similar results.

Weaning rats were divided into three groups. The first group were fed on a synthetic diet deficient in riboflavin. The second group were fed on the same diet but supplemented with riboflavin, and the quantity of the ration was limited to that of the paired animal in the first group. The third group were also on the riboflavin supplemented diet, but fed ad libitum.It was found that anorexia rapidly developed in the deficient animals and thus caused retardation of growth. However, the appetite was quickly restored as soon as riboflavin was supplied. From the results obtained with the pair feeding method, the growth of the deficient animal is somewhat less than the paired control.There was no effect of riboflavin deficiency on nitrogen equilibrium of the rats and on storage of protein in the liver. There was a slight decrease of ammonia nitrogen excretion in the urine during riboflavin deficiency. Slight increase of urinary amino nitrogen was observed only in the early stage of deficiency.

The eight essential amino acid contents of nineteen legumes and cereals of different varieties have been determined with the microbiological methods The methionine and lysine contents of cereals are in general lower than that of animal products. However, the methionine in spiked millet (糜子米) and in panicled millet (小米) and lysine in buck wheat (荞麦) are high. Methionine, tryptophane and isoleucine of the legumes are in general lower than those of the animal products.Past dietary surveys have been re-examined in the light of these analytical results, and a more accurate estimate of the nutritional status of the population, with respect to protein is thereby available.