4 2 ELEMENTARY ZOOLOGY. 



and death, as against a more permanent or, if changeable, 

 a less definite, condition of existence. 



d. The power to use oxygen in the breaking up of some 

 of its compounds and of utilizing the energy derived 

 therefrom directly for the well-being of its life. 



55. Summary. 



1. It will be necessary for the student to know some- 

 thing about the following kinds of matter : 



a. Non-living. 



Entirely unassociated with life unorganized: 



inorganic. 



Organized : 



Merely associated with life, never having been 



alive (starch, shells). 



Matter formerly alive, but now dead. 



b. Living : plants and animals. 



2. All living objects are made up of combinations of 

 living and non-living materials. Even the living matter 

 is made up of elements which are found in nature in a 

 non-living form. 



3. In general, the structural differences between liv- 

 ing and non-living objects may be expressed as follows : 



a. Gross organization, including the facts of general 

 form and the presence of organs and systems of 

 organs to do specific work. 



b. Cellular organization. This refers to the fact 

 that all living objects consist of one or more cells, 

 or units of structure, which have a general uni- 

 formity of character in spite of their great varia- 

 tions in size, shape, and powers. 



c. Protoplasmic organization. This refers to the con- 



