B. LIVING BODIES. 56. =The Wheat Plant and the substances of which it is composed.= Every one has seen a cornfield. If you pluck up one of the innumerable =wheat plants= which are fixed in the soil of the field, about harvest time, you will find that it consists of a stem which ends in a =root= at one end and an =ear= at the other, and that blades or =leaves= are attached to the sides of the stem. The ear contains a multitude of oval grains which are the =seeds= of the wheat plant. You know that when these seeds are cleared from the =husk= or =bran= in which they are enveloped, they are ground into fine powder in mills, and that this powder is the =flour= of which bread is made. If a handful of flour mixed with a little cold water is tied up in a coarse cloth bag, and the bag is then put in a large vessel of water and well kneaded with the hands, it will become pasty, while the water will become white. If this water is poured away into another vessel, and the kneading process continued with some fresh water, the same thing will happen. But if the operation is repeated the paste will become more and more sticky, while the water will be rendered less and less white, and at last will remain colourless. The sticky substance which is thus obtained by itself is called =gluten=; in commerce it is the substance known as =maccaroni=. If the water in which the flour has thus been washed is allowed to stand for a few hours, a white sediment will be found at the bottom of the vessel, while the fluid above will be clear and may be poured off. This white sediment consists of minute grains of =starch=, each of which, examined with the microscope, will be found to have a concentrically laminated structure. If the fluid from which the starch was deposited is now boiled it will become turbid, just as white of egg diluted with water does when it is boiled, and eventually a whitish lumpy substance will collect at the bottom of the vessel. This substance is called =vegetable albumin=.