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.1 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 
1 By an odd coincidence these plants are of the form known as @no- 
thera Lamarckiana, sometimes called G@. biennis var. Lamarckiana, or 
grandiflora. The flowers, curiously enough, have the striking pecul- 
larity of opening suddenly at dusk. 
