CHAP. III. 



FUNCTION OP NUTRITION. 



213 



Maize 



Rice 



\VTieat 



Rye 



Oats 



Peas 



French beans - 



Kidney beans 



Lentils - 



Amomum curcuma 



Dioscorea triloba 



Potato - 



Tapioca (Jatropha manihof) 



Sweet Potato (Ipomaea batatas} 



80 to 92") 

 80 to 85 



70 to 77 



- 61 . 



59 I" seed. 

 50 



- 46 

 34 

 32 



- 26 

 25 

 24 



- 13-5 

 13-3 



Arrow-root (Marantaarundinacea) 12-5 

 Canna coccinea - - 12'5 



Breadfruit (Artocarpus incisd] . 3 '2 



rhizoma. 



tuber. 



root. 



rhizoma. 

 fruit. 



(199-) Sugar. There are numerous modifications 

 of sugar, all of which may be referred to two general 

 heads. The one class, as the sugars of the sugar- 

 cane and beet-root, contains a less proportion of water 

 in combination with an equal quantity of carbon than 

 the other class, which includes the sugars extracted 

 from raisins, manna, &c. Some are crystallisable 

 others not. The purest obtained from the sugar-cane 

 has a specific gravity of 1-605, and is composed of 

 about 42 per cent, of carbon and 58 of water. In the 

 East Indies the canes yield about 17 per cent., and 

 in America 14 per cent, of sugar; but in our hot- 

 houses they produce scarcely any. All sugars are 

 readily soluble in water but less so in alcohol, into 

 which latter fluid they may themselves be converted 

 by the process of fermentation ; thus the quantity of 

 ardent spirits which may be extracted from any vege- 

 table is in proportion to the sugar it contains. This 

 substance bears a striking affinity to gum in its che- 

 mical composition, and is very commonly dissolved 

 p 3 



