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CHAP. XXII. THE EELATIONS OF THE ORGANIC AND INORGANIC 



EVOLUTIONS. 



IT may be of interest to briefly consider the processes of inorganic 

 evolution in relation to those of organic evolution. I have already 

 referred to the fundamental difference in the conditions ; we found 

 evidence of a running down of temperature which no one can define 

 in the case of the stars ; in the case of the organic evolution going on 

 at the present time, we cannot be very much removed from the tem- 

 perature conditions of the Cambrian formations. That is a point 

 which I have made before, and it is important to insist upon it. Clearly 

 there cannot have been any very great change of temperature during 

 the whole cycle of organic life. Previous to it we have found com- 

 plexity brought about, possibly by doublings, and certainly by com- 

 binations, the result being, as I have already mentioned, more com- 

 plex forms. Of course, at the dawn of organic life on the surface of 

 the earth there may have been residua of the earlier chemical forms; 

 that is to say, not all the elements which we found in the hottest stars 

 had combined to form the substances of which the earth was com- 

 posed. However this may have been, although the work of organic 

 evolution, unlike that of inorganic evolution, must have been done 

 under widely different temperature conditions, the result has been the 

 same ; it has since provided us with another succession of forms getting 

 more complex as time has gone on, and there is still a residuum of early 

 forms. 



We are led, then, to the conclusion that life in its various forms 

 on this planet, now acknowledged to be the work of evolution, 

 was an appendix, as it were, to the work of inorganic evolution 

 carried on in a perfectly different way. Although the way was differ- 

 ent, still nature is so parsimonious in her methods she never does 

 a thing in two ways that can be as well done in one that I have 

 no doubt that when these matters come to be considered as they 

 are bound to be considered with the progress of our knowledge, 

 we shall find a great number of parallels ; but I am not concerned 

 with parallels now. I wish to refer to a chemical point of view 

 which I think of some importance in relation to what has gone 

 before ; it is a point which I wish to make depending upon the 

 existence of those elements which make their appearance in the hottest 

 stars. 



