Chapter 6 



PROPERTIES AND ACTIVITIES OF 

 LIVING PROTOPLASM 



L PHYSICAL PROPERTIES OF PROTOPLASM 



The "living" substance of plants and animals is known as protoplasm 

 (pro' to plazm) (Gr. protos, first; plasma, moulded). We consider an 

 organism to be alive when certain activities within the protoplasm result 

 in certain specific, discernible properties and reactions or behaviors which 

 we have decided are characteristic of living beings. Likewise, when 

 these activities within the protoplasm cease, with the cessation of certain 

 reactions and properties, we consider the organism to be dead. Life then 

 might be considered in terms of relative activities of the protoplasm of 

 which living organisms are composed. It has even been theorized that 

 life and death may possibly be relative phenomena. Regardless of this, 

 we know that all things, both nonliving and living, are composed of 

 matter. Matter might be defined as any solid, liquid, or gas which 

 occupies space. From this viewpoint the matter which composes a liv- 

 ing organism is the same matter which that dead organism contains 

 except that it is probably rearranged and thus has taken on different 

 properties and activities. 



Possibly a beginning student in biology may believe that he will be 

 able to see "life" if he merely views living protoplasm highly magnified 

 with a microscope. So far, scientists with the best of equipment have 

 been unable to do so. What have they seen? They have merely ob- 

 served certain characteristics displayed by that living protoplasm, as a 

 consequence of which they conclude that such protoplasm is alive. Just 

 because scientists cannot see "life" or cannot secure the ultimate answer 

 as to what life is is no justifiable reason for not studying living protoplasm 

 to get as much reliable information as possible concerning it. A scientist 

 takes things as they are and as he finds them, and by careful observations 

 and experiments, he secures additional data which may take him only a 



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