SUDDEN ADAPTATIONS 457 



Without going further into the difficulties which Lamarck- 

 ians and Darwinians have had to meet in their endeavors 

 to apply either theory, it must now^ be apparent that neither 

 of them gives promise of affording complete general satisfac- 

 tion to students of nature. It is hard to believe that acquired 

 characters or fluctuating variations are often accumulated 

 in a way to bring about the development of new species. 

 One is thus driven to ask whether there is any possible way 

 of explaining the course of organic evolution without de- 

 pending upon these discredited assumptions. Some of our 

 foremost naturalists believe that this great problem may be 

 solved through the further study of variations, and on the 

 basis of recent discoveries a new theory is developing with 

 which we may hope to incorporate the main truths that have 

 recommended Lamarckism and Darwinism to their advocates. 

 Sudden adaptation, such as we have seen to be implied in 

 the evolution of clematis, and have found to be one of the 

 chief stumbling blocks of former theories, is made the corner 

 stone of the theory we have now to consider. 



169. Sudden adaptations. Professor Hugo de Vries, an 

 eminent botanist of Amsterdam, Holland, was led to a new 

 view of the process of evolution by studying for a number 

 of years the descendants of some large-flowered evening 

 primroses which had been imported from America and had 

 escaped from a garden near his home into a neighboring 

 field where they grew in great profusion, i Among these 

 escaped plants De Vries found a large amount of fluctuating 

 variation in every part, and frequent abnormalities, but what 

 especially attracted his attention was the appearance of 

 two well-characterized forms which he recognized at once as 

 new to science. One of these was distinguished by a short 

 style and no stamens, while the other was peculiar in having 

 smooth leaves of particularly beautiful appearance. Each 

 was represented at first by only a few specimens confined 

 to a particular part of the field as if derived from the seeds of 



^ By an odd coincidence these plants are of the form knowTi as (Ejio- 

 thera Lamarckiana , sometimes called (E. biennis var. Lmnarckiana, or 

 (jrandiflora. The flowers, curiously enough, have the striking pecul- 

 iarity of opening suddenly at dusk. 



