OBJECTIONS AGAINST EVOLUTION. 161 



familiar, to-wit, that some types, both of animals 

 and plants, are more plastic than others. Those 

 which are the most plastic most readily undergo 

 specific transformation, whilst, on the contrary, 

 those which are rigid experience little or no change, 

 even when exposed to very considerable mutations 

 of environment. 



Existence and Cause of Variations. 



Of the existence of variations, numerous and im- 

 portant, there can then be no reasonable doubt. This 

 fact, long known, is daily corroborated by evidence 

 which cannot be gainsaid. But the existence of 

 variations must not be confounded with the cause 

 which originates them, for this, as yet, is shrouded 

 in mystery. Huxley admits this without hesitation 

 and refers to it as follows : " The cause of the pro- 

 duction of variations is a matter not at all properly 

 understood at present. Whether variation depends 

 upon some intricate machinery, if I may use the 

 phrase, of the living organism itself, or whether 

 it arises through the influence of conditions upon 

 that form, is not certain, and the question for the 

 present may be left open. But the important point 

 is that, granting the existence of the tendency to the 

 production of variations, then, whether the varia- 

 tions which are produced shall survive and supplant 

 the parent, or whether the parent form shall survive 

 and supplant the variations, is a matter which de- 

 pends entirely on those conditions which give rise 

 to the struggle for existence. If the surrounding 

 conditions are such that the parent form is more 



