Celluloid

A valuable product of the action of camphor upon pyroxylin. It is prepared in a great variety of forms, both transparent and opaque, colored uniformly or mottled and striated. It cannot be caused to explode by heat, friction, or percu ion. When brought into contact with flame it burns like paper. It di olves in warm, moderately concentrated sulphuric acid, and is also soluble in glacial acetic acid, rapidly in warm, moderately concentrated nitric acid, and in a hot, concentrated solution of caustic soda. The density of celluloid ranges from 1. 310 to 1.393. When heated to 1250 C. it becomes plastic and can be moulded into any desired shape. Separate pieces can also be welded together by simple pre ure at this temperature. It is useful in various ways in surgery. It is used sometimes to form a plastic base for artificial teeth, known by various names, as "Rose Pearl," "Pyroxylin," etc. See Zylonite .