THE THEORY OF MUTATIONS 101 



postulated had not been found to exist. And the 

 equally common rejoinder was that our imper- 

 fection of knowledge as to the geological record 

 was the complete and sufficing explanation of 

 this apparent discrepancy between theory and 

 fact. A number of years have now passed by, years 

 during which unremitting labour has been carried 

 on in the geological field, with, one must admit, 

 surprisingly little effect from the point of view 

 now under consideration. The pedigree of the 

 horse, which, as has been already pointed out in 

 a previous article, is far less clearly demonstrative 

 of the facts which it has been brought forward to 

 prove than it was originally supposed to be, still 

 remains the commonplace of popular books and 

 essays on evolution. It would certainly not occupy 

 its proud position if any more striking examples 

 of the same kind had come to light during the 

 time that has elapsed since this history was first 

 brought forward as proof positive of the truth of 

 evolution. It still remains true indeed, the truth 

 becomes more obvious the more the crust of the 

 earth is examined that the geological record of 

 life is as discontinuous as the discontinuous picture 

 of living nature presented to our eyes to-day. Now 

 this is just what one would not have expected 

 under the Darwinian hypothesis, whilst, on the 

 other hand, it is just what one would have ex- 

 pected had the course of development proceeded 

 by sudden leaps and not by minute accretions of 

 changes. 



Such then are some of the important bearings 

 which de Vries' views have upon the Darwinian 



