CELLULOSE. Every living plant in the world is constantly making that mysterious and complex substance called cellulose. They take water from the ground and carbon dioxide from the air and unite them into a substance closely akin to starch, con taining carbon, hydrogen, and oxygen, which the chemist represents by the formula C6111005. This is the stuff with which plants build up the walls of their innumerable tiny cells. Cellulose is, as a dis tinguished scientist has said, "the very temple of life." It makes up more than one-third of all the vegetable matter in the world.
With all his ingenuity, man has never been able to create a single particle of cellulose. But from the cellulose produced by the plants he has learned to make a thousand things indispensable to modern life. The paper on which these words are printed is nearly pure cellulose. So are the cotton and linen you wear, the jute used for sacks and linoleum, and the hemp, sisal, manila, and other fibers of which rope and twine are made.
More wonderful yet are the many new compounds that chemists have created from cellulose within the last few decades. Treat cellulose fiber in the form of cotton with nitric and sulphuric acids, and you get a violently explosive compound, guncotton (cel lulose nitrate or nitrocellulose). If a less completely "nitrated" form of guncotton is prepared (usually called collodion-cotton or pyroxylin) and dissolved in a mixture of alcohol and ether, the resulting sub stance is the familiar collodion, which we spread over a cut finger to form a "new skin." Squirt collodion through tiny holes in a steel die, and it comes out as threads of silky fiber. This is one of the commonest ways of making artificial silk. Spread collodion over canvas or some other fabric and it dries in a tough film, making a good substitute for leather. Mix collodion-cotton with camphor and alcohol, put it in a hot press, and you get that most useful of artificial plastic substances, celluloid. By treating cellulose with acetic acid instead of nitric acid, cellulose acetate, a substance much like cellu loid, is produced, which has the added advantage of being non-inflammable and hence is used in making motion picture films, windows in automobile cur tains, and transparent coverings for index cards.
Cellulose acetate is also the basis of one of the forms of artificial silk, and of an insulating and protective covering for electric wires. When cellulose is treated with an alkali and then exposed to the fumes of carbon disulphide, it goes into solution as cellulose xanthate. By further treatment this yields "viscose," which is used for making artificial silk and leather and for sizing, waterproofing, and textile printing.