122 THE NATURE AND ORIGIN OF LIFE 



quently, from the start, must give a result adapted to the 

 environment B. 



In order to employ the first method we had to keep to 

 considerations of results of the whole expressed in the chemi- 

 cal language of the quantities of substances, without paying 

 any attention to the existence of a colloid mechanism ; 

 and yet this always serves as the intermediary between 

 external actions and internal chemical phenomena. On the 

 contrary, in the second method we always consider the en- 

 vironment as acting solely on the mechanism and determin- 

 ing secondarily, by means of this mechanism, chemical 

 reactions directed ipso facto in the sense of adaptation. 



In the two cases we have studied the same facts. We 

 ought, therefore, in spite of the divergence between the 

 methods employed, verify some agreement in the results. 

 We succeed in doing this, thanks to a process of reasoning 

 due to Darwin and called natural selection. 



Darwin limited his study of the living world to the veri- 

 fication of the variations accompanying the multiplication 

 of living beings, without attending to the manner in which 

 the variations are produced. Lamarck, on the contrary, 

 connected variations with the law of habit, as we have done 

 in the fourth part of this book. In this way, by trying to 

 bring into agreement the results of our two methods of inves- 

 tigation, we at the same time establish the concordance of 

 the two great schools of Evolution that of Lamarck and 

 that of Darwin. 



Let us take the same example anthrax bacteridium a 

 type which has been thoroughly studied and is easy to ex- 

 plain. Under condition No. 1 (see page 52), in a proper cul- 

 ture bouillon at 35 C., the anthrax bacteridium A mul- 

 tiplies by strict assimilation in its own unvarying likeness. 

 Under condition No. 2, in pure water to which phenic acid is 



