324 . PHYSIOLOGY AT THE FARM. 



nutritive properties it agrees with the other varieties of starch. 

 It is made use of as a substitute for wheat-flour, as being both 

 cheap and tasteless, for thickening gravies, sauces, and the 

 like. 



Wheat-Starch. Wheat-flour contains near 60 per cent of 

 starch, accompanied by from 14 to 19 per cent of the azotised 

 substance termed gluten, a little cellular tissue, and sugar. 



In the ordinary method of procuring the starch of wheat by 

 fermentation much of the amylaceous matter is wasted, and 

 the whole of the gluten is lost, while the gases evolved are of 

 a very offensive nature. By means, however, of a weak solu- 

 tion of alkali, which dissolves the gluten, the starch particles 

 are left unaltered. This method has been chiefly applied, 

 however, to the extraction of starch from rice. Caustic soda 

 is the alkali used to the extent of 1 -350th of the weight of 

 water employed. The rice is first digested in one portion of 

 such an alkaline ley for 24 hours, and, that being drained off, 

 in a second portion of the same ley for the same period of 

 time, while frequent agitation is employed. The liquid being 

 then allowed to rest for a short time, the milky fluid is allowed 

 to run off, from which the starch is deposited. The liquid 

 which floats above the starch contains the gluten, which may 

 be obtained by the saturation of the alkali by means of sul- 

 phuric acid. 



Sago. The name sago is given to the dietetic starch ob- 

 tained from the interior tissue of various species of palms. It 

 is manufactured in the Moluccas, and is imported into this 

 country from Singapore. Three varieties of it are met with 

 namely, sago-meal, pearl sago, and common sago. Sago-meal, 

 called also sago-flour or sago-powder, is a whitish powder, 

 which has been largely employed in the production of a 

 saccharine substance called sago-sugar, made use of, like potato- 

 sugar, to adulterate brown sugar. Pearl sago is in small grains 



