CHAPTER III - THE BODY ORGANIZATION


What is the nature of the body organization? What are the individual
parts, or units, that make it up? What general work do these carry on and
upon what basis do they practice the division of labor? The answers to
these questions will suggest the main problems in the study of the body.

[Fig. 3]


Fig. 3—Diagram showing the relation of the cells and the intercellular
material. _C._ Cells. _I._ Intercellular material.


*Complex Nature of the Tissues.*—To the unaided eye the tissues have the
appearance of simple structures. The microscope, however, shows just the
reverse to be true. When any one of the tissues is suitably prepared and
carefully examined with this instrument, at least two classes of materials
can be made out. One of these consists of minute particles, called
_cells_; the other is a substance lying between the cells, known as the
_intercellular material_ (Fig. 3). The cells and the intercellular
material, though varying in their relative proportions, are present in all
the tissues.

*The Body a Cell Group.*—The biologist has found that the bodies of all
living things, plants as well as animals, consist either of single cells