CHAPTER IV 

 WAYS AND MEANS OF LIVING 



In our human society each individual must obtain the 

 things necessary for existence; the manner by which he 

 acquires them, whether by one trade or another, by this 

 means or by that, does not physically matter so long as he 

 provides himself and his family with food, clothing, and 

 shelter. Exactly so it is with all forms of life. The 

 physical demands of living matter make certain things 

 necessary for the maintenance of life in that matter, but 

 nature has no law specifying that any necessity shall be 

 acquired in a certain manner. Life itself is a circum- 

 scribed thing, but it has complete freedom ot choice in 

 the ways and means of living. 



It is useless to attempt to make a definition of what 

 living matter is, or of how it differs from non-living matter, 

 for all definitions have failed to distinguish animate from 

 non-animate substance. But we all know that living things 

 are distinguishable from ordinary non-living things by the 

 fact that they make some kind of response to changes in 

 the contact between themselves and their environment. 

 The "environment," of course, must be broadly inter- 

 preted. Biologically, it includes all things and forces that 

 in any way touch upon living matter. Not only has every 

 plant and animal as a whole its environment, but every 

 part of it has an environment. The cells of an animal's 

 stomach, for example, have their environment in the blood 

 and lymph on one side, the contents of the stomach on the 

 other; in the energy of the nerves distributed to them; and 

 in the effects of heat and cold that penetrate them. 



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