94 A SCIENTIFIC APPROACH 



theory he produced one of his own. " On planets like the 

 Earth there must always occur at some stage in their evolu- 

 tion the origin, development and disappearance of life, just 

 as there is always a beginning, transformation and dissolution 

 of worlds, and this continues throughout eternity." Terres- 

 trial life is but a particular instance of this cosmic evolution 

 of matter. However, Becquerel, like Schafer, only gave a 

 very rough sketch of the actual evolution of organic matter 

 leading up to the origin of living organisms. 



Like many of his predecessors, Becquerel considered that 

 carbon dioxide ^vas the first carbon compound existing on 

 the Earth. He based his theory, which he called ' radiobio- 

 genesis ', on the experiments of Berthelot and Stoklasa on 

 the synthesis of organic substances from carbon dioxide by 

 the action of ultraviolet and radioactive radiations. Accord- 

 ing to this theory, organic substances arose directly from 

 carbon dioxide, water and minerals under the influence of 

 the ultraviolet radiation of the Sun and the radioactivity 

 of the rocks at some particular geological period. Some truly 

 colloidal systems were later built up and the germs of life 

 developed from these. 



In these hypotheses Becquerel reverts to the possibility 

 which he had explained, that organic substances may develop 

 under the influence of ultraviolet light. However, as con- 

 cerns the cause of the evolutionary formation of the first 

 living things, which is the most important and interesting 

 point to us, his theory still leaves us in the dark, as the author 

 himself admitted. 



In the same year as Becquerel's article appeared, my own 

 little book The origin of life^^ was published. In it I ex- 

 pounded for the first time, though still very schematically, 

 the views which the reader will find more fully worked out 

 in the present edition. In particular, I tried to show in it 

 how the simplest carbon compounds, the hydrocarbons, might 

 have been formed on our planet. The evolution of these 

 compounds was held to lead to the formation of protein-like 

 compounds and then colloidal systems which were able to 

 undergo gradual differentiation of their internal organisa- 

 tion as the result of natural selection. 



Somewhat later, in 1929, J. B. S. Haldane published an 



