HUMAN LIFE 



of all those general conditions and so- 

 called laws of biology such as those of 

 heredity, variation, selection, mutation, 

 growth, the influence of environment, 

 etc., which apply to all living things, to 

 all substance and capacities of substance 

 organized as living matter. 



But he must be prepared to go even 

 farther. The biochemists and physicists 

 have made much progress recently in 

 showing that many of the long-accepted 

 familiar distinctions between living and 

 non-living matter must be given up and 

 that living matter is fundamentally only 

 a much more complex association or 

 state of the same substances that compose 

 other matter and that therefore it is 

 largely controlled in its behavior just as 

 other matter is controlled, namely, by 

 physical and chemical conditions and 

 stimuli. The Royal Society Christmas 

 lectures given in 1916-1917 before Lon- 

 don popular audiences by Dr. Arthur 

 Keith, the famous English anatomist, 

 physiologist, and anthropologist, have 

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