238 THE HISTORY OF CREATION. 



perceive that every apparently free action of the will is 

 the result of previous ideas, which are based on notions 

 inherited or otherwise acquired, and are therefore, in the 

 end, dependent on the laws of Adaptation and Inheritance. 

 The same also applies to the action of the will in all animals. 

 As soon as their will is considered in connection with their 

 mode of life, in its relation to the changes which the mode 

 of life is subject to from external conditions, we are at once 

 convinced that no other view is possible. Hence the changes 

 of the will which follow the changes of nutrition, and 

 which, in the form of practice, habit, etc., produce variations 

 in structure, must be reckoned among the other material 

 processes of cumulative adaptation. 



Whilst an animal's will is adapting itself to changed 

 conditions of existence by the acquisition of new habits, 

 practices, etc., it not unfrequently effects the most remark- 

 able transformations of the organic form. Numerous 

 instances of this may be found everywhere in animal life. 

 Thus, for example, many organs in domestic animals are 

 suppressed, when in consequence of a changed mode of life 

 they cease to act. Ducks and fowls in a wild state fly 

 exceedingly well, but lose this facility more or less in a 

 cultivated state. They accustom themselves to use their 

 legs more than their wings, and in consequence the muscles 

 and skeleton used in flying are essentially changed in their 

 development and form. Darwin has proved this by a very 

 careful comparative measurement and weighing of the 

 respective parts of the skeleton in the different races of 

 domestic ducks, which are all descended from the wild duck 

 {Anas hoschas). The bones of the wings in tame ducks are 

 weaker, the bones of the legs, on the other hand, are more 



