B.—CHEMISTRY 33 
cerned merely the crystalline sugars of the hexose and pentose series which 
are ordinarily accessible as free isolated substances. ‘The simple sugars 
\ 
c#—— 
Furan. 
a Arabo- 
pyranose 
8-Gluco- 
pyranose 
HO 
B-Galakto- 
pyranose 
Pyranose Forms of Pentose and Hexose. 
Normal Pentoses 
H 
a-Xylo- 
pyranos 
HO 
B Manno- 
Ppyranose 
H 
B-Fructo- 
HO HO CHL OH pyranose 
OH H 
Furanose Forms of Pentose and Hexose. 
hO-CH, 
HO- CH. H ho SH 4 
4 OH H OH 
OH 4 H OH 
a-Arabofuranose. a-Glucofuranose. 
Roc on 
HOH 
on H 
B-Fructofuranose. 
acquire their wider significance when regarded as the building-stones 
assembled as the constituent parts of those complex natural products 
comprised in the carbohydrate group. 
It is in such circumstances that 
the allocation of structural forms held in combination whether as a 
di-, tri- or polysaccharide assumes importance, and the allocation of the 
Cc 
