989 
The possibility was considered that within the cell benzaldehyde 
might be formed, whilst at the same time it was proved that out- 
side the cell important quantities of amygdalin by no means should 
be converted into glucose, benzaldehyde and hydrogen cyanide. 
This result was confirmed in another way by a new series of 
experiments, from which it is to be concluded with certainty that 
amygdalin without any preceding conversion into glucose benzal- 
dehyde and hydrogen cyanide, is absorbed by the cells. 
The referential experiments are united in the table. 
From these experiments it follows that the addition of amygdalin 
diminishes the noxious influence of benzaldehyde. Compare £,,F, 
and G, on one side with £,,/,,G, and E,,F,,G, on the other side. 
If a conversion into glucose, benzaldehyde and HCN should 
precede the absorption of amygdalin just. the contrary should be 
stated. 
Physiology. — “Hxperimental researches on the permeability of 
the kidneys to glucose’). By Prof. H. J. Hampurcer and 
R. BRINKMAN. 
I. THE PROPORTION BETWEEN K AND CA IN THE CIRCULATING FLUID. 
(Communicated in the meeting of January 27, 1917). 
1. Introduction. 
No solution has been offered to the question of importance to 
physiologists as well as to clinicists, viz. why the urine of a normal 
person is entirely or all but entirely free from sugar as Jong as 
the sugar-percentage of the blood serum does not rise above a certain 
concentration, and why as a rule glucosuria only sets in when 
accompanied by hyperglycaemia. 
Two explanations suggest themselves: 
It may be supposed that the normal glómerulus epithelium is proof 
against + 0.1 °/, of glucose without becoming permeable to it, but 
eannot keep back all the glucose of a higher concentration. Not 
much can be said in favour of this view, for it is not very likely 
that cells which are permanently exposed to a 0.1 °/, solution of 
a physiological non-electrolyte such as glucose should be changed 
by a 0.2 °/, solution *. 
1) A more detailed account will be published elsewhere. 
2) We shall not discuss here the hypothesis of a glomerulus-epithelium absolutely 
permeable to glucose, with back-resorption of it through the kidney-ducts, nor the 
oxidation of the glucose in the kidney. 
63 
Proceedings Royal Acad. Amsterdam. Vol. XIX 
