THE EVOLUTION OF MAN 



did not arise until the earth had passed the stage 

 of red heat. This would be the historical stage 

 at which the conditions became favorable for the 

 much discussed "spontaneous generation." 



It was necessary to touch upon this rather dif- 

 ficult line of thought at least to this extent, be- 

 cause the confusion which reigns in this regard 

 is very general and fatal. No one can be obliged 

 at present to champion any one of all these 

 theories. But one thing at least must be ad- 

 mitted, we are not in such need of ideas for a 

 natural explanation of life that we are absolutely 

 compelled to seek refuge in miracles. Of course, 

 while we are still in the field of the "natural," 

 we must also admit frankly on the other hand 

 that our actual knowledge of the fundamental 

 problems of life is still so incomplete at this day 

 that it is well to pursue our studies along many 

 different roads. It is quite probable that in our 

 further research along this line, we shall meet 

 many surprises and find many new theories, for 

 we know very little of the internal processes that 

 take place even in the simplest cell. There is 

 still a world before us which we have barely 

 touched. But not all riddles lie concealed on the 

 side of life. We are also far from seeing clearly 

 into inorganic problems, all declarations to the 



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