353 
If this hypothesis was true then besides the d-glucose also the 
l-gulose, |-talose, l-mannose and d-galactose had to be retained. 
(1) d-glucose (2) l-gulose (3) l-talose (4) I- mannose (5)d-galactose 
C—OH C—OH COH GE OH 
| | | | | 
H—C—OH H—C—OH  H—C—OH H—COH H—C—OH 
| | | | 
OH—C—H HCO) sG On ~H—COH OH SCH 
| | | | | 
H—C—OH OH—CH (= @n;OH—C-=H OH-=0=H 
| | | | | 
BSO HO 08. OC OH CH NG): 
| | | | | 
CH,OH CH,OH CH,OH CH,OH CH,OH 
However, of these, only the d-glucose, the l-mannose and the 
d-galactose were at our disposal. 
The experiment showed however that the l-mannose passed through 
completely: In 4 experiments it appeared that in the case of perfusion 
with a solution of 0.09°/, whose reducing power corresponded to 
that of a glucose solution of 0.06 °/,, the artificial urine also had a 
reducing power of 0,06, — there was no retention therefore. Let attention 
be called to the fact, by the way, that after the preparation of the 
l-mannose solution the rotation was + 10.5°, and, 16 hours afterwards 
13.5°. In the following article we shall return to this. 
Concerning the d-galactose, it was not retained completely but 
partly ; to this also we shall return in the next article. 
Our hypothesis further claimed that the following series should 
pass through the glomerular membrane: 
(6) l-glucose (7) d-gulose (8) d-talose (9) d-mannose (10) |-galactose. 
GOH C—OH C—OH C—OH C—OH 
OH_CH OH—CH OH_¢_H OH_C_H OH_¢—-H 
H—C_OH oH_CH OH—¢_H OH_C_H H—¢_OH 
OH—C—H H—C_OH OH-¢_H H—C_OH H—C_OH 
OH—C_H oH-d-H H—C_OH H—C_OH OH_—CH 
| | | | | 
CH,OH CH,OH CH,OH CH,OH CH,OH 
We had only l-glucose and d-mannose available. 
It indeed appeared that the l-glucose in contrast witb the d-glucose 
is allowed to pass through completely. The 0.1 °/, glucose solution, 
dissolved in the customary Ringertluid, showed a reduction of 
