A Rare Carbohydrate in Waxy Maize.

The dextrins, which occur as successive steps in the transition from glucose to starch and from starch to glucose, are so rarely detected in plant tissues and so ephemeral in existence, that their occurrence in stable form in matured or dormant tissues has seldom been reported. It has been the occasion of no little interest, therefore, to find that the sole carbohydrate in the endosperm of “waxy” maize is the rare erythrodextrin.l This variety of corn has been known to science since 1909, when COLLINS (1909) described it as a new type found in China. Besides possessing certain vegetative peculiarities, it has an endosperm distinctly different from that of other varieties, justifying its recognition as a cultural variety coordinate with the flints, dents, pops, etc. The grains of waxy corn are rounded and plump, showing no roughened exterior due to shrinkage a t maturity. The endosperm, although hard like that of flint corn, is opaque, and shows a dull, smooth fracture. Since its discovery in China, this variety has also been found in Burma (COLLINS 1920), and its occurrence in these two places has been considered in connection with claims of a pre-Columbian occurrence of maize in the Orient. The peculiar type of endosperm has also been extensively studied genetically. No one, however, seems to have explained, thus far, the chemical and physical basis of the waxy character itself. COLLINS (1909, p. 15) states: “The appearance and physical composition of the seeds of this Chinese corn were so distinct from that of other varieties that the possibility of a difference in chemical composition naturally suggested itself, but analyses did not yield any very unusual results.” Then follow data from analyses made by the Bureau of Chem-