328 THE INDUCTIONS OF BIOLOGY. 



areas between which migration is possible, while they are 

 markedly divergent in adjacent areas between which migra 

 tion is impossible ? 



Passing to distributions in Time, there arise the questions 

 why during nearly the whole of that vast period geological 

 ly recorded, have there existed none of those highest organic 

 forms which have now overrun the Earth ? how is it that we 

 find no traces of a creature endowed with large capacities for 

 knowledge and happiness ? The answer that the Earth was 

 not, in remote times, a fit habitation for such a creature, be 

 sides being unwarranted by the evidence, suggests the equally 

 awkward question why during untold millions of years did the 

 Earth remain fit only for inferior creatures ? What, again, is 

 the meaning of this extinction of types ? To conclude that 

 the saurian type was replaced by other types at the beginning 

 of the tertiary period, because this type was not adapted to 

 the conditions which then arose, is to conclude that this type 

 could not be modified into fitness for the conditions ; and this 

 conclusion is quite at variance with the hypothesis that creative 

 skill is shown in the multiform adaptations of one type to 

 many ends. 



What interpretations may rationally be put on these and 

 other general facts of distribution in Space and Time, we 

 shall see in the next division of this work ; to which let ue 

 now pass. 



