6o ELEMENTS OF APPLIED MICROSCOPY. 



rated with comparative ease, and is the cheapest of all 

 the starches; but in wheat and rice the union between 

 carbohydrates and albuminoid matter is so close as to 

 introduce serious dif&culties. In the latter case it is nec- 

 essary to use strong alkalies; and with wheat the same 

 end has generally been obtained by moisteniixg and thus 

 swelling the grain, bruising it and then allowing it to 

 stand and ferment until the nitrogenous substance has 

 been partly rotted and disintegrated. The unfortunate 

 feature of this method lies in the necessary loss of the 

 glutinous constituents of the grain which possess high 

 nutritive value; in certain processes the fermentation is 

 omitted and gluten and bran are obtained as by-products. 

 The cost of the various starches depends both on the 

 difficulty of separation and on the value of the raw ma- 

 terials. Its range is indicated by the following list of 

 prices compiled by Dr. H. W. Wiley for the year 1899: 



MEAN WHOLESALE PRICE OF VARIOUS STARCHES. 



Cents per pound. « 

 Corn 1 . 46-1 . 61 



Sago flour 3-73-3 



Potato 4.21-4 



Tapioca flour 4 . 63-4 



Wheat 5 . 00-9 



Rice 7 . 50-9 



98 



57 

 96 

 00 

 00 



3. Commercial Uses of Starch. — Wheat-starch was 

 well known to the ancient Greeks and Egyptians, having 

 been first produced, it is said, in Chios, but it was not 



