Bateson on Variation 



As long ago as 1894 Bateson published his 

 Materials for the Study of Variation, in which 

 he set forth a large number of cases of discon- 

 tinuous variation which he had collected. He 

 pointed out that species are discontinuous, that 

 they are sharply separated one from another, 

 whereas " environments often shade into one 

 another and form a continuous series." How, 

 then, he asked, if variations are minute and con- 

 tinuous, have these discontinuous species arisen ? 

 May not variation prove to be discontinuous, and 

 thus make it clear why species are discontinuous? 



On page 1 5 of the above-cited work we find : 

 "The preliminary question, then, of the degree 

 of continuity with which the process of evolution 

 occurs has never been decided. In the absence 

 of such a decision, there has nevertheless been a 

 common assumption, either tacit or expressed, 

 that the process is a continuous one. The 

 immense consequence of a knowledge of the 

 truth as to this will appear from a consideration 

 of the gratuitous difficulties which have been 

 introduced by this assumption. Chief among 

 these is the difficulty which has been raised in 

 connection with the building up of new organs 

 in their initial and imperfect stages, the mode of 

 transformation of organs, and, generally, the 

 selection and perpetuation of minute variations. 

 Assuming, then, that variations are minute, we 

 are met by this familiar difficulty. We know 



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