72 HOW CEOPS GEOW. 



tion of the flaxseed. The external cells, o, contain the mucilage. When 

 soaked in water, the mucilage swells, bursts the cells, and exudes. 



One or other of these kinds of gum has been found in 

 the following plants, viz., basswood, elm, aj^ple, grape, 

 castor-oil bean, mangold, tea, sunflower, pepper, iu various 

 sea-weeds, and in the seeds of wheat, rye, barley, oats, 

 maize, rice, buckwheat, and millet. 



In the bread-grains, Arabin, or at least a soluble gum, 

 occurs often in considerable proportion. 



TABLE OP THE PKOPOKTIONS (jper cent) OK GtTM IX VAKI0U3 AIE-DKt 

 PLANTS OR PABTS OF PLANTS. 



{According to Yon Bibra, Die Getreidearten und das Brod.) 



"Wheat kernel 4..50 



Wheat flour, superfine 6.25 



Spelt flour, {Trlticmn spelta,) 2.48 



Wheat bran 8.83 



Spelt bran 13,52 



Kj'e keruel 4.10 



Eye flour 7.25 



Kye bran 10.40 



Barley flour 6.33 



Barley hran 6.88 



Oat meal 3.,50 



Eiee flour 2.00 



Millet flour 10.60 



Maize meal 3.05 



Buckwheat flour 2.85 



The gums are converted into sugar by long boiling with 

 dilute acids. 



The recent experiments of Grouven show that, contrary 

 to what has been taught hitherto, gum, (at least gum 

 Arabic,) is digestible by domestic animals. 



Saccharose or Cane Sugar, C„ H,, O,,, so called be- 

 cause first and chiefly prepared from the 

 sugar cane, is the ordinary sugar of com- 

 merce. When pure, it is a white solid, 



readily soluble in water, forming a color- Fig. 14. 



loss, ropy, and intensely sweet solution. It crystallizes in 

 rhombic prisms, fig. 14, which are usually small, as in 



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