C Since vitamin B6(2-methyl, 3-hydroxy, 4,5-di-[hydroxymethyl] pyridine), one of the water-soluble compounds of the vitamin B complex, is a component of yeast and of liver extract, both of which are effective antipellagric substances, it was thought that perhaps this vitamin also might be important in human nutrition. Clinical studies of the effect of vitamin B6on nutritional deficiency diseases were made possible by the recent synthesis1of this substance. We2described recently the study of a large series of undernourished persons who had clinical evidence of pellagra and beriberi and certain symptoms which are corrected by the