78 HOW CROPS GKOW. 



Other sugars. Other sugars or saccharoid bodies occurring in common 

 or cultivated plants, but requiring no extended notice here, are the fol- 

 lowing: 



Mannite, C 6 Hj 4 6 , is abundant in the so-called manna of the apothe- 

 cary, which exudes from the bark of several species of ash that grow in 

 the Eastern Hemisphere, (Fraxinus ornus and rotundifolia.) It like- 

 wise exists in the sap of our fruit trees, in edible mushrooms, and some- 

 times is formed in the fermentation of sugar, (viscous fermentation.) 

 It appears in minute colorless crystals, and has a sweetish taste. 



Quercite, C 6 H 12 O 5 , is the sweet principle of the acorn, from which it 

 may be procured in colorless crystals. 



finite, C 6 H 12 O 5 , exudes from wounds in the bark of a Californian and 

 Australian pine, (Pinus Lambertiana.) Separated from the resin that 

 usually accompanies it, it forms a white crystalline mass of a very sweet 

 taste. 



Mycose, C 12 H 22 O n , is a sugar found in ergot of rye. It may be ob- 

 tained in crystals, and is very sweet. 



Sugar of Milk, Lactose, C 12 H 22 On + H 2 O, is the sweet principle of the 

 milk of animals. It is largely prepared for commerce, in Switzerland, 

 by evaporating whey, (milk from which casein and fat have been sepa- 

 rated for making cheese.) In a state of purity, it forms transparent, col- 

 orless crystals, which crackle under the teeth, and are but slightly sweet 

 to the taste. When dissolved to saturation in water, it forms a sweet 

 but thin syrup. 



Mutual transformations of the members of the Ctlhdose 

 Group. One of the most remarkable facts in the history 

 of this group of bodies is the facility with which its mem- 

 bers undergo mutual conversion. Some of these changes 

 have been already noticed, but we may appropriately re- 

 view them here. 



a. Transformations in the plant. The machinery of the 

 vegetable organism has the power to transform most, if 

 not all, of these bodies into every other one, and we find 

 nearly all of them in every individual of the higher order 

 of plants in some one or other stage of its growth. 



In germination, the starch which is largely contained in 

 seeds is converted into dextrin and glucose. It thereby 

 acquires solubility, and passes into the embryo to feed the 

 young plant. Here it is again solidified as cellulose, starch, 

 or other organic principle, yielding, in fact, 'the chief part 

 of the materials for the structure of the seedling. 



