GLUTEN. With the fecula and sac charine matter which compose the prin cipal part of nutritive grain, is another sub stance, approaching more nearly in its cha racters to animal matter than any other product of the vegetable system. FrQM the resemblance in its properties to the animal principle formerly called gluten, but now described under the term FIBRIN, (which see,) it has received the name of vegetable gluten. It is obtained in largest quantities from wheat, amounting to the twelfth part of the whole grain, by knead ing the flower into paste, which is to be washed very cautiously, by kneading it under a jet of water, till the water carries off nothing more, but runs off co lourless; what remains is gluten : it is ductile and elastic ; it has some resem blance to animal tendon or membrane : it is very tenacious, and may be used as a cement for broken porcelain vessels. It
has a peculiar smell, with scarcely any taste. When exposed to the air it as sumes a brown colour, and becomes ap parently covered with a coat of oil. When completely dry it resembles glue, and breaks like glass. It is insoluble in water, alcohol, and ether ; but the acids dissolve it, and the alkalies precipitate it. It has a strong affinity for the colouring matter of vegetables, and likewise for resinous substances. When kept moist it ferments, and emits a very offensive smell ; the vapour blackens silver and lead. Its con stituent parts are oxygen, hydrogen, car bon, and azote. It exists, as we have ob served, most abundantly in wheat, but it is found in large quantities in many other plants. It is gluten that renders wheat so useful in the art of bread making.