64 MODERN IDEAS OF EVOLUTION 



of these stages the earth would be altogether unsuit 

 able for any forms of life known to us ; but we do 

 not know precisely at what point of the later stages 

 it would be in precisely the best state for the begin 

 nings of life. Let it be observed here, however, that 

 the materials of the physical world are to us manu 

 factured or created products, and that the progress of 

 the development is the result of the properties and 

 laws impressed upon them at first, correlated and 

 regulated to a definite end. We shall find that there 

 is an analogy with this in the origin and development 

 of life. 



But though all this material of the physical world 

 is necessary to life, it manifests in itself no indication 

 of that mysterious power ; for it we require something 



mor e namely, the substance protoplasm, which, so 



far as we know, does not exist in dead nature, and 

 which thus far has baffled all attempts to construct it 

 artificially from its elements. In addition to this we 

 require some form of that complex machinery which 

 we call an organism, though this also, in our present 

 experience, cannot be formed without life. Yet 

 protoplasm and an organism must be present before 

 life can manifest itself. 



Here we have another triad whose relations are 

 enshrouded in mystery. Just as we know nothing of 

 matter, ether, and energy, independently of each other, 

 so we know nothing of protoplasm, organism, and life, 

 except as existing together. We cannot imagine one 



