The distribution of reducing substances between plasma and corpuscles; a comparison of various blood-sugar methods.

THE distribution of "sugar" between plasma and corpuscles has been the subject of much discussion, and the results obtained by different workers have shown wide variation. We shall not attempt to survey the literature here; a summary is given in a paper by Wiechmann [1924]. In view of the work of de Wesselow [1919] it seemed probable that the variation might be, in part, explained by differences in the methods of blood-sugar estimation. De Wesselow compared MacLean's method with the Lewis-Benedict method, and found that whereas the discrepancies between the methods on plasma were small, MacLean's method always gave considerably lower figures on corpuscles. In a preliminary experiment, on oxalated sheep's blood, we made a similar comparison between the methods of MacLean and of Folin and Wu. In addition to the direct determination, the corpuscle-sugar was calculated from the figures for plasma and whole blood, and the haematocrit reading for the. corpuscle volume. The results were as follows (mg. per 100 cc.).