Starch is an important element of food with animals as with vegetables, and its ready convertibility, without change of composition, into suitable forms, such as dextrine and sugar, fits it exactly for carrying on those changes which occur in the juices of vegetables. It is stored up in the seeds, roots and pith of plants, and by its decomposition affords the materials for the most essential vegetable products. Starch, from whatever source, always presents the same chemical characters ; its physical peculiarities may, however, vary slightly. In its pure state, it is a fine, white powder, without taste or smell, and has a peculiar crispness when rubbed between the fingers. It is not soluble in cold water, and on this fact the manufacture, or rather, the extraction, qf starch depends. The simplest method of preparing starch, and separating it from the gluten, and other constituents of wheat, is by washing dough in a linen bag, in a gentle stream of 'water. The usual process, however, whether potatoes, wheat, rice Or maize is treated, is as follows: The substance is crushed, left to steep in cold water, and occasionally agitated; or a quantity of the grain is conveyed, by appropriate machinery, under small jets of water, until all thc starch grains are washed out; thQ water having the fine starch suspended (not dissolved) in it, they are left to settle, and then dried, when they crack into the little prismatic shapes so well known to all consumers of the article. The crushing is a very inconvenient operation, especially with indian corn; and Mr. Watt, of Belfast, Ireland, has taken out a patent in this country for the manufacture of starch from indian corn whole. His process is as follows, and in our opinion will be found to answer perfectly :He first takes the car of corn, and steeps it in water for a week, keeping the water at any temperature betvreen 70 and 140 Fah, and changing the water several times. In this there will be a slight fermentation, and as soon as it has ceased, the corn is taken out and ground to a kind of powdery pulp, as it is quite soft from the steeping. Warm water of the above temperatures must be kept running through the millstones, and this will carry away the starch ; the water is passed through the seives, or other arrangement for catching the starch, and the whole is allowed to settlethe clear water being run off, and the starch dried and packed as in older processes. It was patented June 30, 1857.