318 DARWINISM AND THE PROBLEMS OF LIFE 



Chlorophyll is much too complex a structure for us to 

 suppose it to have been present from the first. No, 

 these biogens were clearly like the actual nitrogenous 

 bacteria, very simple organisms, that can convert lifeless 

 into living matter. 



The next step in the development of life was that the 

 biogens, which were at first quite homogeneous, clustered 

 together like stars. External conditions were acting 

 constantly on all these primitive beings, because it is 

 the nature of the living substance to be flexible and 

 modifiable. We can thus understand that the activity 

 of the biogens, in creating their like before they broke 

 up, would be greater in warm and well-lit places than in 

 less favourable ones. Here we have the first cause of 

 differentiation. If we further remember the great diver- 

 sity of the earth's surface, we can see that this of itself 

 would lead to a considerable variety among the living 

 things, since each locality would have a different effect 

 on the changeable living matter. Thus the Lamarckian 

 principle was active at the beginning of biological 

 evolution. Even when a group of biogens divided 

 and formed two, the halves retained the modifications 

 that had been imprinted on the parent by external 

 conditions. 



But it would be otherwise when a differentiation set 

 in among the biogens in a given group. The moment 

 a favourable division of labour was introduced amongst 

 them, the organism would be in a better position, and 

 would be picked out by natural selection. By this 

 division of labour one biogen would be better able to 

 discharge one vital function, a second another one, and 



