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REV. J. T. GTTLICK ON DIVERGENT EVOLUTION" 



such a way as to ensure increasing divergence in each successive 

 generation, as long as the individuals of the two groups are kept 

 from intergenerating. In my paper on Diversity of Evolution 

 under one Set of Exteriial Conditions, I spoke of this principle of 

 divergence as " Separation with Variation;" but in order to dis- 

 tinguish the antecedent condition, which is Separation, from the 

 result, which is something niore than Variation, I now call the 

 certainty that some form of divergent transformation will arise 

 when intergeueration is prevented the principle of Intension 

 and Segregation produced by independent transformation I call 

 Intensive Segregation. 



As Separate and Segregate Generation are so closely related, 

 I have, in order to avoid a multiplication of terms, classified the 

 two principles together under the general term Segregation. In 

 my discussion of the causes of Segregation I shall, however, 

 endeavour to determine concerning each class of causes whether 

 they are primarily Separative or Segregative. 



A full discussion of the causes of Segregation would require 

 that under each combination of causes to which we give a dis- 

 tinctive name we should show : — 



1. How the Independent G-eneration is produced. 



2. How the difference of character in the different sections is 

 produced. 



3. How the aggregation in place bringing together the members 

 of each section is produced. 



4. How the correspondence in times and seasons necessary for 

 intergeueration is secured within each section. 



5. How the correspondence of community and of Sexual and 

 Social instincts necessary for intergeueration is secured within 

 each section. 



6. How the correspondence in structure, in dimensions, and 

 in the mutual potentiality of the sexual elements necessary for 

 intergeueration is secured within each section. 



It will, however, be observed that, with the exception of the 

 two first, these questions relate to the necessary conditions that 

 must always exist in the case of every intergenerating group ; 

 and as it is evident that intergeueration in some degree must be 

 the normal condition in every sexual, that is in every gamo- 

 genetic, species, we may here assume that all the conditions 

 necessary to intergeueration exist, except so far as they have 

 been disturbed by causes producing Segeneration. In tracing 



