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LIFE AND MIND 



THERE are three kinds of change in the world 

 in which we live — physical and mechanical 

 change which goes on in time and place among the 

 tangible bodies about us, chemical change which 

 goes on in the world of hidden molecules and atoms 

 of which bodies are composed, and vital change 

 which involves the two former, but which also in- 

 volves the mysterious principle or activity which 

 we call life. Life comes and goes, but the physical 

 and chemical orders remain. The vegetable and 

 animal kingdoms wax and wane, or disappear en- 

 tirely, but the physico-chemical forces are as inde- 

 structible as matter itself. This fugitive and evanes- 

 cent character of life, the way it uses and triumphs 

 over the material forces, setting up new chemical 

 activities in matter, sweeping over the land-areas of 

 the earth like a conflagration, lifting the inorganic 

 elements up into myriads of changing and beautiful 

 forms, instituting a vast number of new chemical 

 processes and compounds, defying the laboratory 

 to reproduce it or kindle its least spark — a flame 

 that cannot exist without carbon and oxygen, but 



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