THE BODY ORGANIZATION 19 



In the connective tissue they deposit the fibrous material 

 so important in holding the different parts of the body 

 together. In the cartilage they 

 produce the gristly substance which 

 forms by far its larger portion 

 (Fig. 7). In the bones they de- 

 posit a material similar to that in 

 the cartilage, except that with it 

 is mixed a mineral substance which 



gives the bones their hardness 



, ,_, . FIG. 7. Cartilage cells, 



and stiffness. 1 The intercellular surroun ded by the intercel- 



material, in addition to connecting lular material which they 

 the cells, supplies to certain tissues have de P sited - 

 important properties, such as the elasticity of cartilage 

 and the stiffness of the bones. 



Nature of the Body Organization. The division of labor 

 carried on by the different organs, as shown in the pre- 

 ceding chapter, is in reality carried on by the cells that 

 form the organs. To see that this is true we have only to 

 observe the relation of cells to tissues and of tissues to 

 organs. The cells form the tissues and the tissues form 

 the organs. This arrangement enables the special work 

 of different kinds of cells to be combined in the work of 

 the organ as a whole. This is seen in the hand which, in 

 grasping, uses motion supplied by the muscle cells, a con- 

 trolling influence supplied by the nerve cells, a framework 

 supplied by the bone cells, and so on. The cells supply 

 the basis for the body organization and, properly speaking, 

 the body is an organisation of cells? (Recall the definition 



1 Certain of these cells also form deposits of fat, giving rise to the adipose, or 

 fatty, tissue. 



2 Any organized structure, such as the body, whose parts are pervaded by a 

 common life, is known as an organism. The term "organism" is frequently ap- 

 plied to the body. 



