of Edinburgh , Session 1885 — 86 . 
971 
Malic acid, 
Glyoxylic acid, 
CH(OH) . CO . OH 
I 
ch 2 . CO . OH . 
CHO. 
I 
CO . OH . 
The above ten examples of substances possessing distinct acid 
tastes are taken from various classes of organic acids, and they will 
be seen to have in all cases a common group of elements. This 
group is a compound radical CO . OH . which is combined in all 
cases with a different molecule. We have then the same right to 
impute to this radical the capacity of producing a given taste sensa- 
tion as the chemist has of looking upon it as related to certain 
physical properties of the compounds in which it may be found. 
Among sweet substances we find the following : — 
CH 9 . OH 
Glycol, . 
• . 1 
CH 2 . OH . 
CH 2 . OH 
| 2 
Glycerine, 
CH OH 
1 
CH 2 . OH. 
Mannite, 
. . C 6 H 8 (OH) 6 
Glucose, 
C 6 Hi 2 0 6 
Inosin, . 
C 6 Hi 2 0 6 
Saccharin, 
C 12 H 22 O n 
These are all alcoholic bodies, glycol, glycerine, mannite, being 
respectively a diatomic, triatomic, and hexatomic alcohol. The 
rational formulae of the last three, and other nearly related sub- 
stances, such as levulose, maltose, &c., are not at present definitely 
settled ; but it is certain that they are alcoholic or ether bodies, and 
contain a radical CH 2 . OH found in the first three substances. 
Thus the formula of glucose, according to Colley, is CH 2 . OH - 
CH . OH . - CH . OH - CH . OH - CHOH - CHO . 
Monatomic ethyl alcohol is tasteless, and has been alluded to 
already. It is the simplest alcohol, the polyatomic alcohols referred 
to having a sweet taste. 
