Physiology. — “A direct proof of the impermeability of the blood- 
corpuscles of man and of the rabbit to glucose’. By S. van 
Creverp and R. Brinkman. (Communicated by Prof. H. J. 
HAMBURGER). 
(Communicated at the meeting of December 18, 1920). 
1. Introduction. 
The question dealing with division of glucose between the red 
bloodeorpuseles and the bloodplasma, which has been discussed so 
often already in the literature, has come to the front again through 
recent research. 
In 1919 one of us together with Miss EK. van Dam published a 
series of researches*) which clearly demonstrated that the permea- 
bility of the bloodeorpuseles for glucose is intimately related to the 
process of coagulation, and that the bloodcorpuscles of the frog and 
of man are found to be impermeable to gluclose only when the 
earliest incipiency of coagulation has been prevented. In the case 
of the frog the physiological impermeability could be shown by 
direct chemical analysis. 
Such a direct chemical proof could at that time not be given for 
the human bloodcorpuscles. In the osmotic experiments these blood- 
corpuscles were invariably found to be impermeable in cases where 
the blood had not yet coagulated, and it was held that all the 
authors who had found the bloodcorpuscles to be permeable to sugar 
had used blood of which the commencement of coagulation had not 
been prevented. 
Shortly after this publication there appeared an article by W. Farra 
and M. Ricnter-QuirTNer’*) on the distribution of sugar, chlorides 
and residual-N between plasma and bloodcorpuscles in the circu- 
lating blood. Also these investigators came to the conclusion that in 
man the sugar in the blood occurred only in the plasma. The 
method used by them could be considered as a direct chemical one. 
They determined the amount of sugar in the blood as a whole and 
in the plasma, and from these two values calculated the volume of 
the bloodcorpuscles, taking for granted that all the sugar occurred 
1) BRINKMAN and v. Dam. Arch. Intern. de Physiologie XV. 105. 1919, 
*) Fatra and RicHTER—QvuITTNER: Biochem. Zeitschr. 100. 140. 1919. 
