210 BLOOD SUGAR 



colloidal investment might be carried along in the precipita- 

 tion of the other blood colloids and thus escape estimation ; 

 while in the sense of "virtual sugar" it would be recognized 

 as soon as freed from its investment in the lecithid by any 

 suitable separating agent. Whether this, in a general way, 

 will satisfactorily explain the activity of glucoside-splitting 

 ferments, as understood by Lepine and Boulud, must be 

 left unanswered. But at any rate we cannot insist specifi- 

 cally upon lecithids as the enveloping factors. 



Sugar Content of the Red Blood Cells. In the last few 

 years the question whether glucose is found in the red blood 

 corpuscles as well as in serum has been freely agitated. The 

 statement that these cells contain, not glucose, but only a non- 

 fermentescible carbohydrate, a polysaccharide, 57 is appar- 

 ently contradicted by numerous investigations. There is suf- 

 ficient positive evidence 58 that the red cells of fresh blood (in 

 contrast with washed cells, which vary) 59 are permeable for 

 glucose and actually absorb it (in addition, the corpuscles, 

 as well as the plasma, contain variable amounts of a complex 

 carbohydrate which is converted into fermentescible sugar 

 by hydrolysis). The sugar is not always in proportionate 

 distribution in the plasma and cellular elements ; sometimes, 

 especially in hyperglycaemias, very striking differences have 

 been found in the proportionate amounts found within and 

 outside the corpuscles, which has been taken to indicate that 

 the blood cells play an independent role in sugar metab- 



87 H. Lyttkens and J. Sandgren (Instit. Med. Chem., Lund), Biochem. 

 Zeitschr., 26, 382, 1910; Z, 153, 1911; 36,261,1911; S. E. Edie and DL Spence 

 (Liverpool), Biochem. Jour., 2, 103, 1907. 



58 L. Michaelis and P. Rona, Biochem. Zeitschr., 16, 60, 1909; 18, 375, 514, 

 1909; 37, 47, 1911; P. Rona and A. Doblin, ibid., 31, 215, 1911; R. Lupine and 

 Boulud, ibid., 32, 287, 1911, and earlier contributions; A. Hollinger (Frankfurt 

 a. M.), ibid., 17, 1, 1909; D. Takahaschi (Rona's Lab.), ibid., 37, 30, 1911; 

 E. Frank and A. Brettschneider (Wiesbaden), Zeitschr. f. physiol. Chem., 76, 

 226, 1911. 



89 Consult the studies of Hamburger, Gryns, Koeppe, Hedin and others: 

 Literature upon the Permeability of Red Blood Cells: E. Overton, Nagel's 

 Handb. der Physiol., 2, 828-839, 1907. 



