642 VIS MEDICATRIX NATURAE 



evolution have not got it, but the invention was too good 

 to lose; and every one knows that all backboned animals 

 from fishes onwards have red blood. Or again, the most 

 primitive and in a way most puzzling kind of locomotion 

 is that of the amoeba flowing along, or rolling along like 

 a microscopic * tank ' in the pond. Is it not a most sug- 

 gestive fact that our health from day to day, and the de- 

 velopment of our nervous system, are absolutely dependent 

 on this self-same amoeboid movement? Our white blood- 

 corpuscles are amoeboid cells; the outgrowth of nerve-fibres 

 in development is in some measure due to amoeboid move- 

 ment How far this evolutionary conservation of values 

 goes, who shall say ? In any case there seems good reason 

 for regarding evolution as essentially integrative. By this 

 we mean that it makes for co-ordination, consistency, har- 

 mony in the continual self-realisation of multitudinous 

 forms of being. Ugliness, evil, inconsistency are disintegra- 

 tive lapses that perish; beauty, goodness, truth even in 

 little bits are integrative qualities that last. In any case, 

 the big fact is, that men, bent on making much of their 

 life, have behind them an organic momentum which is in 

 part in line with what the best in us regards as best. 



Purpose and promise. When we consider the grandeur of 

 the long-drawn-out Evolution process and the wonder of its 

 masterpieces, and especially when we realise its general 

 progressiveness and its conservation of great gains, two ideas 

 rise in the mind purpose and promise. 



It is difficult to shut out the impression that Nature is 

 Nature for a purpose. We do not think any longer of a 

 1 directive power ' outside of the evolving organisms, but 

 of a directive power which is bone of their bone and flesh 

 of their flesh, a directive power analogous to that which 



