138 MAMNA. 



Grape Sitp&r Sugar ( f Starch. Diabetic Surar 



(Saussufe.) (Gutrin.) (Pelig-oi.J 



Carbon 36.7 36.1 36.4 



Hydrogen 6.8 7.6 7.0 



Ozygen .56.5 56.9 56.6 



100.0 100.0 100.0 



Like cane su^r, grape sugar in combining with certain bases 

 ibandons a portion of its constitutional water. In the state in which 

 it is combined with the oxide of lead it contains — 



Carbon 43.3 



Hydrogen 6.3 



Oxygen 50.4 



iooio 



From these analyses it appears that crystallized grape sugar con- 

 sists of — 



Anhydrous glucose 100 



Water 19 



On comparing the two kinds of sugar in the crystallized state, it 

 becomes evident that glucose or grape sugar does not differ from 

 cane sugar, except in containing a larger quantity of water. In fact 

 the composition of grape sugar may be represented in this way : 



Carbon 42.2 i 



Hydrogen 6.2 > 100 of cane sugar. 



Oxygen 51.6) 



115.8 of grape sugar. 



The cane, the beet, the palm, the maple, the vine, and starch, 

 turned into glucose, are the sources from whence all the sugar of 

 commerce is obtained at the present day, although attempts more or 

 less successful have also been made to extract sugar from the pine- 

 apple, from the chestnut, from the sweet orange, and from the stem 

 of the maize or Indian corn. It appears that before the conquest 

 the Mexicans prepared a sirup from the stem of the Indian corn, 

 which was sold in the market-places. Pallas could not obtain more 

 than about 3 per cent, of crystallized sugar from maize, but in "xn 

 experiment which I made in South America along with M. RouL.i, 

 the quantity of raw sugar obtained from this plant was 6 per cent. 



SACCHARINE PRINCIPLES NOT FERMENTABLE. 



Manna ; mannite. This saccharine principle is met with in dif- 

 ferent plants ; it has been found in the expressed juice of onions, 

 and in that of asparagus, in the alburnum of several species of pine- 

 trees, and in different mushrooms. Manna, which is an exudation 

 from the fraxinus omus and larch, contains nearly ^ths of its weight 

 of mannite, and it is therefore from this substance that mannite is 

 usually obtained, although it can also be had from the juice of the 

 beet and the onion ; but then it is necessary to destroy the cane or 

 grape sugar which they contain by pre^ jous vinous fermentation, 



