Origin of Different Kinds of Adaptations 371 



out discussion, and that in some cases the length of life and 

 the coming to maturity of the germ-cell may be, in some way, 

 physiologically connected seems not improbable ; but that this 

 relation has been regulated by the competition of species 

 with each other can scarcely be seriously maintained. I will 

 not pretend to say whether the mutation theory can or can- 

 not be made to appear to give the semblance of an explana- 

 tion of the length of life in each species, but it seems to me 

 fairly certain that this is one of the questions which we are 

 not yet in a position to attempt to consider on any theory of 

 evolution. 



Organs of Extreme Perfection 



It has often been pointed out that certain organs may be 

 more perfectly developed than the requirements of the sur- 

 roundings strictly demand. At least we have no good reasons 

 to suppose in some cases that constant selection is keeping 

 certain organs at the highest possible point of development, 

 yet, on the Darwinian theory, as soon as selection ceases 

 to be operative the level of perfection must sink to that 

 which the exigencies of the situation demand. The prob- 

 lem may be expressed in a different way. Does the animal 

 or plant ever possess organs that are more perfectly adapted 

 than the absolute requirements demand ? If such organs 

 are the result of fluctuating variations, they will be unable 

 to maintain themselves in subsequent generations without 

 a constant process of selection going on. If, on the other 

 hand, the organs have arisen as mutations, they may be- 

 come permanently established without respect to the degree 

 of perfection of their adaptation. We can see, therefore, 

 that cases of extreme perfection meet with no difficulty on 

 the mutation theory, while they have proven one of the 

 stumbling-blocks to the selection theory. 



There are, in fact, many structures in the animal and plant 

 kingdoms that appear to be more perfect than the require- 



