1. An account has been given of the composition and weights of nutrients and sugars in sixty-four sugar beet plants from just before singling until maturity. The assimilation, translocation and distribution of these have been discussed.
2. At about singling, the leaves contained 90 per cent. of the dry matter and 76 per cent. of the sugars of the plant, whereas, at maturity, the figures were 28 and 3 per cent. respectively.
3. The percentage of reducing sugars in the dry substance of the complete plant maintained a steady level throughout, as was also the case with cane sugar in the leaves. The highest percentages of sugars in the dry matter of both leaves and roots were attained by early August. Evidence is produced to show that, although in the plant as a whole carbon assimilation proceeded more quickly than the intake of soil nutrients, until early July the rate of translocation of carbon to the roots did not equal the rate of intake of soil nutrients by the latter.