r, as a result of his exhaustive studies of the
chemical constitution of the various carbohydrates. There is, of course, no
thought that the printed formulas here presented accurately represent the
actual relationships in space of the different groups; but there is fairly
conclusive evidence that the variations in special groupings in the
different sugars are properly referable to the particular asymmetric carbon
atoms as indicated in the several formulas as presented.

1. Aldohexoses of the mannitol series:

_d_-Glucose _l_-Glucose _d_-Mannose _l_-Mannose
CH_{2}OH CH_{2}OH CH_{2}OH CH_{2}OH
| | | |
H-C-OH HO-C-H H-C-OH HO-C-H
| | | |
H-C-OH HO-C-H H-C-OH HO-C-H
| | | |
HO-C-H H-C-OH HO-C-H H-C-OH
| | | |
H-C-OH HO-C-H HO-C-H H-C-OH
| | | |
CHO CHO CHO CHO

_d_-Gulose _l_-Gulose _d_-Idose _l_-Idose
CH_{2}OH CH_{2}OH CH_{2}OH CH_{2}OH
| | | |
HO-C-H H-C-OH HO-C-H H-C-OH
| | | |
H-C-OH HO-C-H H-C-OH HO-C-H
| | | |
HO-C-H H-C-OH HO-C-H H-C-OH
| | | |
HO-C-H H-C-OH H-C-OH HO-C-H
| | | |
CHO CHO CHO CHO

_d_-Altrose _l_-Altrose _d_-Allose _l_-Allose
(unknown) (unknown)
CH_{2}OH CH_{2}OH CH_{2}OH CH_{2}OH
| | | |
H-C-OH HO-C-H H-C-OH HO-C-H
| | | |
HO-C-H H-C-OH H-C-OH HO-C-H