355 
(4) d-arabinose (5) d-xylose (6) d-lykose (7) l-ribose 
C—OH C—OH C—OH €—OH 
OH_¢_H . OH—C_H OH_C_H OH-C-H 
H—C_OH H—¢_OH OH_CH OH—C_H 
H_—¢_OH oH_¢_H H—C_OH oH_¢_H 
CH,OH CH,OH CH,OH CH,OH 
Of these 4 pentoses we were able to investigate only the first 
two; quite in accordance with what was to be expected there was 
no question of any retention of d-arabinose. 
It was different in the case of d-xylose of which again a part 
was retained. 
Let us add to this still that neither of the d-l-arabinose nor of 
the d- and l-arabinose anything was retained. 
The tetroses could not be examined; if this had been the case it 
was to be expected that 
d-erythrose and d-threose 
C—OH C—OH 
H—C_OH H—¢_OH 
H—C_OH OH_C_H 
CHLOH CH,OH 
would be retained and 
l-erythrose and l-threose 
C—OH C—OH 
OCH OH_C_H 
OH_C_H H—C_OH 
CH:OH CELOH 
allowed to pass through. 
To simplify the survey we give here a table in which the results 
of the experiments are summed up. Let it be remarked here however 
that with d-galactose and l-xylose a much larger amount of experi- 
ments have been make. These will find a place in the following article. 
Summarising the results of the above described experiments 
we must come to the conclusion that the hypothesis which makes 
