Abstract

By blood sugar concentration is meant the content of glucose in the blood.Our knowledge of the amount of glucose in the blood is derived almost exclusively from reduction methods.Besides glucose, however, the blood contains other reducing substances; viz., fructose, ketones, uric acid, creatinine, etc.Whether the blood sugar values obtained by the reduction methods give only the amount of glucose or whether other reducing substances also play a part in the reduction has often been discussed.Determination of the actual amount of glucose in the blood is not easy.One cannot rely on polarimetry, as the blood contains several substances which act optically.It is best to ferment the blood and determine the reduction before and aft.er.But the fermentation also may introduce errors.In part the yeast may contain reducing substances, or these may be formed during fermentation; in part the fermentation of glucose is, as a rule, more or less incomplete; and in part it may well be supposed that the reducing substances of the blood which are not subject to fermentation may be converted into non-reducing substances when the blood is in process of fermentation.Several investigators have attempted to ascertain whether fermented blood contains a reducing substance, and whether a so called residual reduction exists after fermentation.They have obtained discordant results, which seem to be due partly to the methods used.Thus Frank and Bretschneider (1) found no residual reduction by Bertrand's method, either in normal people or in diabetics with hyperglycemia.Maase and Tachau (2) found substantial agreement between Bertrand's copper method, 347