It has been known for several decades that there is a reducing substance in the cerebrospinal fluid. At first, there was a question whether the reducing substance was glucose or pyrocatechin. Now, however, the presence of glucose in cerebrospinal fluid is beyond doubt, most workers agreeing with Schloss and Schroeder1 that "the reducing substance in cerebrospinal fluid is a fermentable, dextrorotatory sugar, probably dextrose."
The amount of sugar in normal cerebrospinal fluid was found by the older authors to vary between 36 and 148 mg. per hundred cubic centimeters of fluid. More recent studies place the amount of sugar in cerebrospinal fluid between 40 to 75 mg. per hundred cubic centimeters of fluid.
Of late, some comparative studies have been made on the sugar contents of blood and cerebrospinal fluid under normal conditions and in cases of encephalitis. Special mention should be made of the work of Seham and
LEVINSON A. COMPARATIVE SUGAR CONTENT OF BLOOD AND OF CEREBROSPINAL FLUID IN VARIOUS CONDITIONS. Am J Dis Child. 1925;30(6):774–779. doi:10.1001/archpedi.1925.01920180034003