Note 15 — Chapter III · ORGANISM, ORGANIZATION, AND ORGANIC SUBSTANCE.

Here organization is the simplest form of all—molecular organized structure, which in the higher forms becomes tissue structure, and organ structure. The word structure properly means orderly arrangement of different materials; and molecular structure refers to the different proximate principles which constitute the organized substance. Usually, however, the word structureless indicates the absence of visible arrangement of the parts; a cell has structure since it has nucleus and protoplasm.