-STARCH OR FEC\JLA, 13^ 



wibstances either actually poisonous, or possessing a sharp, 

 bitter, acrid, or otherwise disagreeable taste : it is there- 

 fore of the greatest consequence that the fecula should be 

 prepared from them with the utmost attention to freeing 

 it from every other portion of the plant. Fortunately the 

 uature of the substances which are united with tlie fecula 

 is so different from that of the fecula itself, and the char- 

 acteristics of each are so distinct, and so well marked, 

 that they can be separated from each other by a process 

 equally easy and sure. The great solubility in water of 

 all the injurious principles, and their extreme levity when 

 compared with the weight of the fecula, causes them, when 

 exposed to repeated washings, to rise to the top of the 

 vessel in which the operation is performed, whilst the 

 fecula, freed from any mixture, remains at the bottom. 



Two processes are employed for extracting fecula ; both 

 must be commenced by reducing to a state of fine division 

 the substance containing it The fecula is afterwards 

 obtained either by means of cold water alone, or by fer- 

 mentation. The first of these methods is the most simple 

 and expeditious, but by it all the fecula is not obtained; 

 the second, therefore, though longer and more expensive 

 is preferred for extracting starch from the grains. 



When starch is to be extracted by cold water, the sub- 

 stance must either be reduced to the state of flour, or be 

 broken so that the pulp can be acted upon by the water. 



In the first case, the flour of wheat is kneaded with 

 water, till it takes the consistency of a stiff paste ; this is 

 placed on a cloth stretched tightly over a tub, and cold 

 water thrown upon it ; the kneading with the hand is 

 continued till the water runs off clear ; the fecula is car- 

 ried off by the water and deposited at the bottom of the 

 tub ; the water retains in solution the sugar and the ex- 

 tractive matter of the farina, whilst the insoluble gluten 

 alone remains upon the filter ; the deposit is washed to 

 free it from any foreign substance, and then dried. When 

 it is not wished that the substance containing the fecula 

 should be reduced to flour, it may be broken in a mortar, 

 or under a mill-stone, or it may be grated ; the pulp is then 

 to be placed upon a very fine horse-hair sieve, and water 

 thrown upon it till it runs off clear; care being taken to 

 stir the pulp constantly with the hand and to squeeze it 

 hard. 



When the substance from which the fecula is to be e/- 

 12* 



