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substance analogous to manna has been extracted 
by Fourcroy and Vauquelin, from the juice of the 
common onion (. Allium Cepa). 
Besides the crystallized and solid sugars, there 
appears to be a sugar which cannot be separated 
from water, and which exists only in a fluid form ; 
it constitutes a principal part of melasses or treacle ; 
and it is found in a variety of fruits : it is more 
soluble in alcohol than solid sugar. 
The simplest mode of detecting sugar is that 
recommended by Margraaf. The vegetable is to 
be boiled in a small quantity of alcohol ; solid 
sugar, if any exist, will separate during the cooling 
of the solution. 
Sugar has been extracted from the following 
vegetable substances. 
The sap of the Birch ( Betula alba), of the Sy- 
camore ( Acer Pseudoplatanus ), of the Bamboo 
(. Arundo Bara bos), of the Maize (Zea mays), of 
the Cow Parsnip ( Heracleum Spondylium), of the 
Cocoa-nut tree ( Cocos nucifera ), of the Walnut- 
tree ( Juglans alba), of the American Aloe (Agave 
Americana ), of the Dulse ( Fucus palmatus), of the 
Common Parsnip ( Pastinica saliva ), of St. John’s 
bread (Ceratonia Siliqua) ; the fruit of the com- 
mon Arbutus ( Arbutus Unedo), and other sweet- 
tasted fruits ; the roots of the Turnip ( Brassica 
Rapa), of the Carrot ( Daucus Carota ), of Parsley 
(Apium petroselinum), the flower of the Euxine 
Rhododendron (. Rhododendron ponticum ), and from 
the nectarium of most other flowers. 
The nutritive properties of sugar are well known. 
At the time the British market was over-stocked 
