Physiology. — “The partial permeability of the glomerular membrane 
to d-galactose and some other multi-rotatory sugars’. By Prof. 
H. J. HAMBURGER. 
(Communicated in the meeting of September 27, 1919). 
Through earlier experiments it has appeared already that d-galactose 
is only partially retained *) by the glomerular membrane. Upon 
closer examination, however, this appears to agree very little with 
the idea of permeability, because a filter either holds back a 
substance or allows it to pass through unconditionally. A mean 
between these two extremes can hardly be conceived when there 
is question of only a simple substance and: not of a mixture. As a 
matter of fact at first we were inclined therefore to drop the idea 
of permeability, but, as appears from the preceding article we 
endeavoured in vain to clear up the matter with the help of surface 
tension, viscosity or adsorption. For this reason we then returned 
again to the idea of permeability. 
On closer inspection two explanations still seemed possible to us: 
ist. The concentrations of the galactose-solutions which had been 
used up to this (0.1°/, and 0.15 °/), might have been too strong 
that is above the toleration of the kidney for d-galactose. We were 
mindful here of our experience in connection with glucose; for, did 
we not find formerly ’), that, when the concentration of glucose in 
the perfusion liquid exceeded the physiological value only by 0.02 °/,, 
already a little of the glucose was suffered to pass through, and, 
that this quantity inereased in proportion as the concentration of 
sugar in the perfusion liquid became stronger, so that when the 
concentration of glucose had become 0.2 °/, practically no sugar was 
retained any longer? There was a possibility therefore that also the 
concentration of galactose might have been too strong and that it had to 
be ascribed to this that it was partly retained and partly not. /¢ was 
therefore desirable to make determinations of the toleration of the 
kidneys for d-galactose. Should it appear then that the galactose 
could not, like the glucose, be wholly retained even in weak con- 
1) HAuBURGER and Brinkman, These Proc. 28 Sept. 1918. 
1) Hampurcer and Brinkman, Biochem. Zeitschr., 88, 97, (1918). 
