tXVlll 



Hi MUTATION, MENDELISM, ETC. 



There is no dispute between Darwinians and Muta- 

 tionists as to the germinal origin of variation and 

 hereditary individual difference of every kind and degree. 

 Darwinians hold that evolution has proceeded by small 

 steps : Mutationists hold that it has advanced by large 

 ones. That I believe to be the sole essential difference, 

 and the reconciliation will come when, joining hands 

 with the student of geographical distribution, and un- 

 deterred by cheap sneers about ' ingenious persons ' and 

 'demonstrating the obvious', Darwinians shall have proved 

 that the relations of an organism to its environment are so 

 accurately and elaborately adjusted that any advance by 

 large variation is only possible as a very rare coincidence. 

 In that day the Mutationist will discover that ' something 

 mistakably like continuous evolution ' has occurred. 1 



There are indications that Mutation would still be 

 claimed as the method of evolution, even if advance by 

 large variations were to be abandoned. Any such con- 

 tention has been effectively dealt with by F. A. Dixey : 

 'If it be replied that a well-adapted type must have 

 arisen, not by one or more large mutations, but by a series 



important contribution of its size which has ever been made to biological 

 science.' A subject is injured rather than advanced by such language. 

 Excessive inflation naturally tends to undue depression. Mendel's principle 

 has not yet been applied to a large number of species, and important 

 exceptions have been already revealed. (Bateson, Report British 

 Association, 1904, p. 581.) Complications have appeared which are as 

 yet imperfectly understood and have immensely increased the complexity 

 of an explanation which appeared at first to be of singularly beautiful 

 simplicity. The hypothetical germinal mechanism which a few years ago 

 seemed to accommodate the facts so comfortably is already beginning to 

 creak and groan. I am not aware that such an assertion as Lock's 

 has ever been made for the Darwin-Wallace essay of 1858, with nearly 

 half a century of prolific work as the firstfruits of its harvest. 



1 ' When the unit of segregation is small, something mistakably like 

 continuous evolution must surely exist.' Bateson, in Report British 

 Association, 1904, p. 577 n. 



