230 EVOLUTION OF TO-DAY. 



could be developed by the accumulation of minute 

 variations. The variations of animals under ordi- 

 nary circumstances are very slight, so slight, indeed, 

 that only one long accustomed to breeding animals 

 can distinguish them ; yet it is such minute varia- 

 tions that natural selection is supposed to make use 

 of. Darwin, indeed, believed that natural selection 

 is much more exact than is the artificial selection of 

 breeders, picking out constantly features which the 

 eye cannot detect. But while this may be true in 

 some cases, it is hardly possible to believe that most 

 of these small variations can be of enough import- 

 ance to be selected. When accumulated they may 

 undoubtedly be of importance, but in order that 

 natural selection may accumulate them, it is neces- 

 sary that each one must be of so much importance 

 as to lead its possessor to a great superiority over 

 other animals. To take one or two examples : 

 The potto (a lemur) has the peculiarity of having 

 only three fingers, the forefinger being a mere 

 rudiment. Now whether this peculiarity be of any 

 use to the animal, it is impossible to say ; but grant- 

 ing that it is of use, it must be assumed that at one 

 time in the ancestors of the potto this finger was 

 equal in size to the others, and that it has gradually 

 diminished in size. If variations are minute in ex- 

 tent, this shortening of the finger must have been 

 very slow ; and it is hardly possible to believe the 

 shortening of the finger by a slight fraction of an 

 inch at a time could have been of any use to the 

 animal, even though the completely rudimentary 

 finger is of advantage. When we consider that not 



