CONCLUSION 277 



Nevertheless, organic evolution will in time be 

 overtaken and destroyed by inorganic evolution. As 

 the temperature of the earth falls, the tropical vege- 

 tation will die out, as also will the animals which 

 depend upon it for food. Next will follow the tem- 

 perate flora and fauna ; and finally those of the arctic 

 regions. The arctic flora and fauna will take posses- 

 sion of the former tropical regions ; but only for a 

 time. The last to succumb will be the lowest forms 

 of life, which were also the first to appear. At last 

 death will come to all, and mind will vanish from the 

 earth. What will become of it? According to the 

 materialistic monist it is utterly destroyed. But the 

 dualist or the idealistic monist can believe that men- 

 tal evolution may still go on, and that it is only its 

 present protoplasmic surroundings which will disap- 

 pear for ever. 



Now how does life, or mind, or vital-force 

 whichever we choose to call it act? How does it 

 bring about movements ? The first process is for a 

 special kind of protoplasm, called chlorophyll-cor- 

 puscles which we know so well as the green 

 colouring matter in leaves by means of the setherial 

 undulations of sunlight to decompose, at ordinary 

 temperatures, the carbonic-acid in the air, and from 

 the carbon thus obtained to build up hydro-carbons, 

 like starch. This appears to be a purely chemical 

 process, but it is as yet quite unknown to chemists. 

 The starch is changed into sugar and dissolved in 

 cell-sap. Some is reconverted into starch and stored 

 for future use, while another portion combines with 

 the nitrogen of the nitrates, brought in through the 



