332 THE THEORIES OF EVOLUTION 



burned to death, few animals are able to detect poi- 

 son in their food, rabbits often devour their young or 

 abandon them, birds set on their nests although there 

 may not be one egg left, etc., etc. 



Thus far we have only mentioned injurious organs 

 and instincts; many more cases could be instanced of 

 indifferent organs and instincts. And, as the injuri- 

 ous and indifferent organs and instincts, put together, 

 are probably more numerous than the useful ones, we 

 must not judge too severely the phylogenetic theories 

 which fail to solve the problem of adaptation. 



Certain adaptations being taken for granted, there 

 remains to be seen not only whether the results of 

 adaptation can be transmitted to the offspring, but 

 whether adaptation originates in the function or in 

 the structure. This is the line of cleavage between 

 Darwinians and Lamarckians. Does the mole pos- 

 sess paws adapted to burrowing because it had to 

 burrow, or does the mole burrow because it has paws 

 whose conformation makes that sort of work espe- 

 cially easy? No direct experimental proof is obtain- 

 able ; the answer to this question must be subordinated 

 to whatever system we adopt. Our knowledge con- 

 cerning the insufficiency of natural selection (which 

 by the way is based on structure) leads us to seek 

 an explanation in functional stimulation whose action 

 lasts during the entire life of the organism and also 



