440 VEGETABLE SUBSTANCES. 



they are stiffened and rendered of an apparently 

 greater consistency. It is likewise, by a subsequent 

 process, rendered applicable to the service of the calico- 

 printer, by whom it is much employed. 



Starch is prepared from wheat: this being well 

 cleansed is steeped in vessels of water, which are 

 exposed to the sun; the water is changed twice a 

 day during the period of eight, or sometimes twelve 

 days, according to the heat of the season. A slight 

 fermentation is then induced, which is considered to 

 have been sufficiently excited when the grain bursts 

 freely under the finger. Thus softened, it is put 

 into canvas bags, in order to separate the flour from 

 the husks. This separation is performed by rubbing 

 and beating the grains enclosed in the bags, while 

 laid on a plank placed across the mouth of an empty 

 vessel, which is to receive the flour, as mixed with 

 water it runs through the bags. 



Or, instead of being put into these bags, the grain 

 is, from the steeping vessel, removed to a tub of water, 

 and trodden upon. By this operation the starchy 

 part is washed out, and, mingling with the water, gives 

 to it a milky appearance. This fluid is then drawn 

 off through a sieve into another vessel, called the sit- 

 ting-tub. Fresh water is effused on the grains, and 

 the same process is continued until the water in the 

 treading-tub no longer becomes turbid. While the 

 starch is subsiding in the sitting-tub, the water at the 

 surface assumes a reddish hue ; this should be care- 

 fully removed from time to time, and replaced by clean 

 water, and the whole should then be stirred together. 

 Sometimes it is again strained through a cloth, the 

 starchy particles are returned into the vessel, and the 

 water is entirely renewed. The starch now gradually 

 precipitates by repose from the water in which it was 

 held suspended, during which, sometimes, and espe- 

 cially if it be a warm season, the mucilaginous sac- 

 charine matter of the flour held in solution by the water 



