60S Willis .— The Origin of Species by Large , rather than by 
that it must be easy of acquisition. It is obviously inconceivable that all 
can be descended from a common climbing ancestor. Now in the case of 
herbaceous climbers, such as are common in the north, it may be just possible 
to conceive that weakness of the stem was graduall)^ acquired, for there 
is but little woody tissue in any case; but how is this supposition to be 
applied to tropical lianas with large woody but flexible stems ? Is it con¬ 
ceivable that the stems of the trees and large shrubs which make up much 
of the genus Bauhinia , for instance, were gradually selected for weakness 
till the lianas were produced ? Some of the climbing Bauhinias have 
tendrils, and some twine. Did the latter wait till the utterly useless 
and dangerously disadvantageous weak stems had been selected down to the 
point where they became flexible, before they began to evolve the twining 
habit by selection ? Yet they could not begin to select the twining habit till 
the weak stems had been arrived at, and a weak stem, with no means of 
support, in a tropical forest would stand a very poor chance. And why do 
some species twine and some climb by tendrils ? One has only properly to 
realize the enormous difference between the stem of a tree and that of 
a woody climber, and the entire lack of use-value in any small change in 
strength or rigidity, together with the hopeless position of a weak stem with 
no means of support, to realize at the same time the total absurdity of the 
* explanation ' provided by Natural Selection. It is difficult to have long 
experience, in the tropics at any rate, without being convinced of its utter 
and pathetic inadequacy as an explanation of the facts, as I was convinced 
about 1899, after three years in Ceylon, and have tried to make clear on 
numerous subsequent occasions. 
Though previous to about 1890 criticism had little or no effect, the 
reverence in which Natural Selection was held has since diminished, more 
especially with the rise of biometrical measurements and statistics, which 
showed that the universally occurring fluctuating variations upon which 
Darwin mainly depended were not fully hereditary, but exhibited regression 
to such an extent that improvement by their means was not possible beyond 
a certain point. Another strong bar to its acceptance was the growth of 
Mendelism, which was quite incapable of explanation upon this theory. 
At the same time de Vries was elaborating the theory of Mutation ( 3 ), 
according to which progress in evolution took place by fixed and hereditary 
changes that at times appear suddenly, in the form commonly known as 
sports ; and it is with de Vries that the credit of the change from the 
Darwinian view of very gradual alteration really lies. Much subsequent 
work has shown reason to believe that his mutations in Oenothera do not 
rest upon sufficient evidence, regarded as mutations. This, however, is but 
a locking of the stable door after the emergence of the theory of Mutation, 
which has come out to stay. It is steadily gaining ground, and at the 
present time the older theory of progress by means of fluctuating variations 
