124 EVOLUTION 



bility, it will tend to re-establish itself, but 

 if the range is overpassed, it will topple over 

 into a new position; also that both of them 

 are more likely to topple over towards the 

 position of primary stability than away 

 from it." 



THE MUTATION THEORY. In 1900 Pro- 

 fessor Huffo de Vries of Amsterdam published 

 under the title "The Mutation Theory" an 

 account of his very interesting and important 

 experiments and observations on the origin 

 of species in the vegetable kingdom. The 

 most striking of his conclusions was that 



ni|fi l^fpff ft.Tifl jimmd^ as opposf;(J to a. 



Whereas Darwin relied on 



the action of selection on minute individual 

 variations or fluctuations, Ete Vries believes 

 th^t these have nothing to do with the origin 

 ". "all 



Let us quote some of his char- 

 \acteristic statements. 



"By the ^pnitatiqji theory ^ mearL, the 



consist of ..rlisijjftj p^parrf^ and 



These um'ts c^n be 



a.T]d| WP finrl r in 



u,nits,^Jid groups of units. Transitions, such 

 as we sofrequently meet with in the external 

 form both of animals and plants, are as com- 



