20 ARE THE EFFECTS OF USE INHERITED? 



being able to reach otherwise inaccessible stores of 

 foliage. The continual variability of all parts of 

 the higher animals gives scope for innumerable 

 changes, and Nature is not in a hurry. Mr. 

 Spencer, however, says that "the chances against 

 any adequate readjustments fortuitously arising 

 must be infinity to one." But he has also shown 

 that altered degree of use does not cause the 

 needed concomitant variation of co-operative 

 parts. So the chances against a beneficial change 

 in an animal must be, at a liberal estimate, infinity 

 to two. Mr. Spencer, if he has proved anything, 

 has proved that it is practically impossible that 

 the giraffe can have acquired a long neck, or the 

 elk its huge horns, or that any species has ever 

 acquired any important modification. 



Mr. Wallace, in his Darwinism, answers Mr. 

 Spencer by a collection of facts showing that 

 " variation is the rule," that the range of varia- 

 tion in wild animals and plants is much greater 



