CHEMICAL CONSTITUENTS OF BODY AND FOOD. 
1, Monosaccharides (C 6 H 12 6 ). 
group are : 
Dextrose. 
Levulose. 
-The most important members of this 
Galactose. 
Mannose. 
2. Disaccharid.es (C 1 oH o0 11 ). — The most important members of this 
group are : 
Cane Sugar. Maltose. 
Lactose. Isomaltose. 
3. Polysaccharides (C 6 H 10 O 6 ) n . — The most important members of this 
group are : 
Starch. 
Glycogen. 
Dextrins. 
Cellulose. 
Tunicin. 
Gums. 
Inulin. 
The monosaccharides. — When an alcohol is oxidised, the first 
stage in oxidation is the formation of an aldehyde, or a ketone ; if 
oxidation of the aldehyde is continued, an acid is formed. 
When more complicated alcohols are oxidised, similar products result. 
The monosaccharides are the first oxidation products of the hexatomic 
alcohols (CH,.OH— (CH.OH)— CH 2 OH). 
Of the hexatomic alcohols, three are known, namely sorbite, mannite, 
and dulcite. 
Dextrose is the aldehyde of sorbite. 1 
Mannose ,, „ mannite. 
Galactose ,, ,, dulcite. 
Levulose „ ketone of mannite. 
Sugars of the monosaccharide group may thus be either aldehydes, 
when they are called aldoses] or ketones, when they are called ketoses. 
Dextrose, mannose, and galactose are aldoses, and have the structure 
represented by the following formula : — 
CH,OH— (CHOH) — CHO 
They differ from one another in then stereochemical formula\ 
Levulose is a ketose, and has the structure represented by — 
CH,OH— (CH.OH.)— CO— CH. 2 — OH 
The difference between the aldoses and ketoses is shown by oxidation, 
levulose, like all ketoses, yielding acids which are poorer in carbon. 
If chlorine or bromine water is used as the oxidising agent, the 
aldoses (dextrose, mannose, and galactose) give isomeric monobasic acids 
of the formula — 
CH,.OH— (CH.OH) — COOH ; 
and then, by further oxidation by means of nitric acid, yield dibasic 
acids of the formula — 
COOH— (CH.OH) 4 — COOH 
Both sets of acids are stereo-isomerides. 
From Dextrose 
,, Mannose 
,, Galactose 
Monobasic acid. 
Gluconic acid 
Mannonic acid 
Galactonic acid 
Dibasic acid. 
Saccharic acid. 
Manosaccharic acid. 
Mucic acid. 
1 Meunier, Compt. rend. Acad. d. sc. 
ibid., p. 51. 
Paris, tome cxi. p. 49 ; Vincent and Delachanal, 
