PHYSIOLOGY. . 833 
and tuberous roots of many plants, ¢.g. the horse 
chesnut, (Aesculus Hippocastanum) ; mn the potatoe, 
(Solanum tuberosum) ; in the bryony, (Bryonia 
alba); in Paeonia officinalis, Arun maculatum, az 
many others. 
14. Sugar. This is Hess obtained from a great 
-number a plants, of which, however, few yield pure 
sugar, most of them only amass like honey, con- 
sisting of the sugar dissolved in a gelatinous Huid 
from which it cannot be extracted in a state of pu- 
rity. Pure sugar is found in the juice of the sugar- - 
cane, (Saccharum offcinarum). Some species of the 
Acer, especially of the Acer saccharinum, dasycarpum, 
some species of birch, (Betula alba, lenta and free), 
Cabbage, (Brassica oleracea viridis); beet, (Beta 
vulgaris. Plums, cherries, and other fruits leeitadn 
sugar. ' 
A honey-like substance is prepared in the! nec- 
faries of most plants, ¢.\g. of. the manna-ash tree, 
(Fraxinus Ornus and rotundifolia), of the liquorice 
root, (Glycyrrhiza glabra), &c. 
15. Bitter principle. .Many plants possess this 
principle, as the common wormwood, (Artemisia 4)- 
syntbium); water trefoil, (Menyanthes trifoliata); céen- 
taury, (Chironia Centaurium) ; common fumitory, 
(Fumaria officinalis); Quassia amara, and others*. 
16. INa- 
*' The nature of the bitter principle of plants is not yet 
suficiently known, for it differs from that which we find in 
bitter almonds, in the stones of peaches, apricots or plums, in 
the leaves of the cherry laurel, inthe seeds of Strychnos Nux 
DVOMICA, 
