369 
/H—C—OCHs | CHO—C—H 
H—C—OH uk Bot 
OH—C—H ieee oe OH-C-H 
EC Seita 
CH20OH CH20H 
a-methy l-l-xyloside 8-methyl-l-xyloside, 
the first of which is converted by invertine and the second only by 
emulsine, and which were distinguished by Fiscner as « and 8. 
Suppose the CH, substituted by H, then «- and p-xylose is formed 
again. 
Similar experiments as were made with galactose were also made 
with xylose. We give a table which contains the experiments in 
question (see table III). 
From this table it appears that the l-xylose, like the d-galactose, 
is not retained completely either. Always the greater portion passes 
through the glomerular membrane, a greater portion percent, however, 
than was the case with d-galactose; between '/, and '/, only of the 
xylose, used in concentrations which do not affect the production 
of artificial urine, on an average is retained. 
We now find, according to von Lippmann’) for the rotation of the 
l-xyloses: initial rotation + 78°, final rotation + 19°. Therefore, the 
a-form has a rotation of + 78°; the g-form however has up to this 
not been isolated, and therefore it cannot be stated, how much of 
this modification takes part in the final rotation of + 19°. Also for 
xylose it is therefore not possible to indicate the form, which is 
retained by the kidneys, and which is allowed to pass through. 
That the glomerular membrane possesses the property of separating 
two sugars quantitatively like a sieve, retaining one and letting the 
other pass through, we have formerly been able to show with 
mixtures of glucose and fructose, and glucose and lactose’). 
Let us remark that researehers who are engaged upon distin- 
guishing of sugars by means of microbes*) have to reckon with 
1) Von Lippmann, Chemie der Zuckerarten. 
*) HAMBURGER and BRINKMAN, These Proc. Sept. 28th 1918. 
5) C.f. among others A. J. Kuuyver, Biochemische Suikerbepalingen. Diss. Delft 1914. 
W. C. pe Graarr, De biochemische eigenschappen van paratyphusbacillen, 
Leiden, S. C. van DoesBuren, 1919. 
