28 THE USES OF PLANTS. 



seven heads, the food-adjuncts forming an eighth : 

 (i) Starches and the Cereals or Bread-stuffs; (2) 

 Sugars ; (3) Pulse, seeds rich in nitrogen, largely as 

 casein ; (4) Roots and tubers, watery and mostly 

 amylaceous, non-green 'vegetables'; (5) Stems, leaves, 

 fruits and whole plants, mostly eaten green, as ' vege- 

 tables,' i.e., with salt ; (6) * Fruits,' commonly so called, 

 watery and saccharine, containing also acids and fre- 

 quently pectin ; (7) ' Nuts/ oily fruits and seeds. 



I. STARCHES AND BREAD-STUFFS.* 



STARCH, having the composition C 6 H 10 O5-f-2H 2 O, 

 or perhaps C 36 H 62 O 31 + I2H 2 O, is perhaps the most 

 important force-producer in human food. It occurs in 

 the leaves, stems and seeds of most plants that contain 

 chlorophyll, being one of the first products of the pro- 

 cesses of assimilation, and being stored up in many 

 tubers, etc., as a reserve- material, in characteristic 

 granules. It is largely used for other purposes besides 

 food, viz., in calico-printing, in dressing textile fabrics, 

 for laundry purposes, as adhesive paste, in toilet powder, 

 and in the manufacture of dextrine, or British gum, and 

 of glucose, or starch-sugar. It was formerly separated 

 from the grain, mainly of Wheat, by a process of 

 steeping and fermentation, which removed the other 

 constituents of the grain ; but in 1840 Orlando Jones 

 patented its separation by dilute caustic potash, which 

 rendered possible its preparation from Rice.-f- Heat 



* F. Crace-Calvert, 'Journ. Soc. Arts,' viii (1859), 87. J. 

 Paton, ' Encyclopaedia Britannica,' vol. xxii. 



f P. L. Simmonds, ' Commercial Products of the Vegetable 

 Kingdom,' 1854. 



