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quantity of “combined sugar” in bloodserum which does not ultra- 
filtrate. 
3. As to cerebro-spinal fluid, the results do not yet give sufficient 
certainty concerning the exact proportions of its sugar-percentage 
and that of blood-plasm; to all appearance it is considerably lower 
than it is in the liquid of the eye-chamber. We wish to indicate the 
possibility of accounting for this difference by assuming a larger 
glucose-consumption in the cerebral tissues than occurs in the tissues 
lining the eye-chamber. 
4. Krom the fluctuations in the sugar-percentage of eye-chamber 
liquid under normal conditions and with hyperglycaemia after 
adrenalin-injection we must conclude that the equilibrium with the 
blood is here chiefly caused by diffusion and hardly by the circulation 
of liquid; such corresponds to what is accepted about the speed of 
circulation of the eye-chamber liquid. On the other hand, the so- 
called secondary liquid of the eye-chamber is, as regards its sugar- 
percentage, perfectly equal to blood plasm at the same moment. This 
is accounted for as follows: what has entered is practically blood- 
plasm with a high percentage of colloids and a corresponding quantity 
of combined sugar. 
5. In comparing arterial blood from the a. carotis and venous 
blood from the v. facialis posterior it appeared that the difference 
of sugar-percentage between these two is to be ascribed to the 
free sugar which is therefore yielded to the tissues. | 
6. The hyperglycaemia caused by adrenalin-injection depends 
entirely on an increase of the free sugar. 
| Physiological Laboratory. 
Groningen, March 1921. 
