n 



6to 



THE BEGINNINGS OF LIFE, 



been exposed to great changes of climate and have 



0- 



migrated over great distances ^ j whereas in Egypt durin 

 the last 3000 years the conditions of life, as far as we 

 know, have remained absolutely uniform.' Mr. Darwin 



then adds: 'The fact of little or no modification 



having been effected since the glacial period would be 

 of some avail against those who believe in an innate 

 and necessary law of development, but is powerless 



J F 



against the doctrine of Natural Selection or survival of 

 the fittest, which implies only that variations or indi- 

 vidual differences of a favourable nature occasionally 

 arise in a few species, and are then preserved.' The 

 facts above cited are, however, not at all inconsistent 

 with a belief in progressive development, when this 



itioned. And 



me 



eluding 



modifyi 



1 Mr. Spencer would perhaps suggest that their migration may have 

 been one of the means of protecting them from such changes of chmate. 



2 ( 



Principles of Biology,' vol. i. p. 199. 



im 



aevefl 



for 



I Thequestior 

 of the exi 



tion 



IT 



■fsent tlay, 

 ijto that conce 



sKalled Persis' 

 The Foramii: 



the absen 



tk extreme si 

 in spite of th' 



there are, moreover, very excellent reasons for be- 

 lieving that the structures of higher organisms are much ] stroctures whic 



i 



to rank 



amor 



less easily modified than those of lower organisms. Mr. 



Spencer sums up the results of his interesting specula- ' mal substance 



tions on this subject in the following words ^ :— « With- ^ ttat of Amceb; 



out assuming fixity of species, we find good reason for 



anticipating that kind and degree of stability which is 



observed. We find grounds for concluding a priori that 



an adaptive change of structure will soon reach a point 



beyond which further adaptation will be slow ; for con- 



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