INTRODUCTION The effect of diet on the blood sugar of normal individuals was reported by Jacobson1 in 1913 and by Strouse2 in 1915. Bang's monograph3 appeared in 1913 and contains a full discussion of blood sugar, both normal and pathologic. Since 1915, as a result of the perfection of chemical methods easily adaptable to the clinical laboratory, the study of blood sugar has become a clinical procedure. All methods in common use report results in grams per 100 c.c. of total blood or blood plasma; and a large collection of valuable data has resulted, especially in regard to diabetes mellitus and to other pathologic states. Not a great deal of attention has been directed to normal variations, although present methods are so simple that studies of the same individual for a long period of time are easily performed. "Normal" values vary from 0.06 to 0.10 or 0.12 per cent., and