THE PROBLEM 49 



part of the soma from the rest for purposes of agamic 

 reproduction. 



5. Somatic death results from an organic disharmony 

 of the whole organism, initiated by the failure of some 

 organ or part to continue in its normal harmonious func- 

 tioning in the entire differentiated and mutually depend- 

 ent system. This functional breakdown of a part may 

 be caused in a multitude of ways from external or internal 

 sources. It may manifest itself in a great variety of 

 ways both structurally and functionally. Many of these 

 manifestations which have been regarded as causes of 

 senescence, may more truly be considered concomitant 

 attributes of senescence. 



6. As a consequence of our second thesis which postu- 

 lated life to be a mechanism, death, whether of a single 

 somatic cell or of a whole soma, is a result of physico- 

 chemical changes in the cell or organism; and these 

 changes are in accordance with ordinary physico- 

 chemical laws and principles. 



7. The time at which natural death of the soma occurs 

 is determined by the combined action of heredity and 

 environment. For each organism there is a specific long- 

 evity determined by its inherited physico-chemical con- 

 stitution. This specific longevity is capable of modifica- 

 tion, within relatively narrow limits, as a result of the 

 impact of environmental forces ; the chief mode of action 

 of the environment being in the direction of determining 

 the rate at which the inherited endowment is used up. 



For no one of the separate elements of this picture can 

 I claim any particular originality. Most of them would 

 probably be agreed to at once, at least by some biologists. 

 The need is for a synthesizing into a consistent whole of 

 a wide range of data, which have accumulated in various 



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