r 



THE THEORY OF ORGANIC EVOLUTION. 433 



to the assumption of the piecemeal variation of mi- 

 nute parts. It seems, according to De Vries, as if 

 the organism as a whole — through its germinal or- 

 ganisation, of course — may suddenly pass from one 

 position of organic equilibrium to another. This con- 

 sideration, and actual measurement, seem also to sug- 

 gest that there is a greater definiteness and a less 

 fortuitousness in variation than was previously sup- 

 posed. 



Origin of Variations. — In his great work, Ma- 

 terials for the Study of Variation, Mr. Bateson de- 

 votes a line to saying that enquiry into the causes is 

 in his judgment premature ; and it must be admitted 

 that until we know the actual facts better, we can- 

 not expect to say much that is wise in regard to their 

 antecedents. A number of suggestions have been 

 made, however, and some of these may be briefly 

 stated. 



A variation, which renders the child different 

 from its parents, is often interpretable as due to 

 some incompleteness of inheritance or in the expres- 

 sion of the inheritance. It seems as if the entail 

 were sometimes broken in regard to a particular 

 characteristic. Oftener, perhaps, as the third gen- 

 eration shows, the inheritance has been complete 

 enough potentially, but the young creature has been 

 prevented from realising its entire legacy. Contrari- 

 wise, it may be that the novelty of the newborn is 

 seen in an intensifying of the inheritance, for the 

 contributions from the two parents may as it were 

 corroborate one another. 



But in many cases something turns up to which 

 we irresistibly apply the word novel, some peculiar 



♦See Fourth Edition, 1901, 

 28 



