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 then said to have neutralized each other, and the resulting substance is called a salt. The salt may be obtained by evaporating the water of the solution. Most common minerals are salts. If the last experiment is tried with soda and sour buttermilk, the demonstration will show some of the facts involved in bread making with the use of these substances.

Test for Starch.—Starch turns blue with iodine. The color may be driven away by heat, but will return again as the temperature lowers. Procure a few cents' worth of tincture of iodine and dilute it. Get a half dozen pieces of paper and cardboard, all different, and test each for starch by placing it over mouth of bottle and tipping the bottle up. If much starch is present the spot will be blue-black or dark blue; if little starch, pale blue; if no starch, brown or yellowish.

Make pastes with wheat flour, potato starch, and corn starch. Treat a little of each with a solution of rather dilute tincture of iodine. Try grains from crushed rice with the same solution. Are they the same color? Cut a thin section from a potato, treat with iodine and examine under the microscope.

To study Starch Grains.—Mount in cold water a few grains of starch from each of the following: potato, wheat, arrowroot (buy at drug store), rice, oats, corn. Study under microscope the sizes, forms, layers, fissures, and location of nuclei, and make a drawing of a few grains of each.

Test for Grape Sugar.—Make a thick section of a bit of the edible part of a pear and place it in a bath of Fehling's solution. After a few moments boil the liquid containing the section for one or two minutes. It will turn to an orange color, showing a deposit of an oxid of copper and perhaps a little copper in the metallic form. A thin sec-