644 VIS MEDICATRIX NATURE 



strumental music. It is to the progressive Amphibians of the 

 Carboniferous Age that we must look back with special 

 gratefulness, for they were the first to get vocal cords, and, 

 interestingly enough, a movable tongue. With them Animate 

 Nature found a voice. 



In a much deeper sense, however, we may say that for 

 millions and millions of years Nature was speechless — never 

 more than groaning and whispering, as it were. It was in 

 Man that Nature became definitely articulate; that the in- 

 herent rationality was echoed. In poem and painting Man 

 expresses his aesthetic appreciation and partial understand- 

 ing of the system of which he forms a part; in his science 

 he turns darkness into light; in the application of science 

 he conquers and controls the world. 



Every one recognises as a big fact of animate evolution the 

 growing differentiation and integration (i.e., organisation) 

 of living creatures, but another side to it is the progressive 

 external registration. There has been woven a web of 

 life whose pattern has become more and more intricate, as 

 for instance in the inter-relations between flowers and 

 flower-visiting insects. This complexifying of inter-relations 

 has been of great importance in evolution, for it is in refer- 

 ence to this external system that experiments are tested 

 or even made, and that selection works. Thus, as it seems 

 to us, the intensification of life has been in part secured 

 and in part prompted by the growing complexity of the 

 external Systema Naturae. Thus living creatures contribute 

 to the evolution of their kind not only directly by exhibiting 

 variations and by personally testing these, but also indirectly 

 by making new patterns in the web of life. If this be 

 so, there is for Man the hint — the Open Secret — that pro- 

 gressive evolution depends not merely on the improvement 



