ACQUIRED VARIATIONS 141 



with, the environmental force or cause at work. The effect 

 must be harmonious with the cause. 



The acquired variation is a "character " in the organism 

 manifesting it ; it is the proper response for existence in 

 the conditions producing it, or a response whose " pur- 

 pose " is to be the true effect of the cause. Every 

 acquired variation must be adaptive. It must be useful, 

 it cannot be useless, for the organism which manifests it ; 

 that is, it cannot be useless for life in the environmental 

 conditions which produced it. 



The dwarfed and stunted plant's deformity is specially 

 useful for life in the hostile environment which produced 

 the deformed habit, and there is as much " purposive adap- 

 tation " exhibited here, in our opinion, as in the growth 

 of an aerial plant-root towards a small localised collection 

 of water. Naturally, it is only occasionally that we can 

 recognise the cause which is at work, and this is no doubt 

 largely due to the fact that the modifying force begins its 

 action during the early development of the affected organism, 

 when we cannot detect change at all. There is " purpose " 

 in the movements of a molecule ; these are adaptive in 

 response to surrounding environmental influences ; they 

 are the effect of such causes. 



The acquisition of a variation implies sudden environ- 

 mental action or change. This might act directly on the 

 organism or part concerned, or indirectly by allowing- sudden 

 response to modifying forces previously held in check. 

 Theoretically, one organism out of a collection enjoying an 

 absolutely uniform environment could not acquire variation, 

 for all would develop in harmony with the common environ- 

 ment. When one organism out of a number exhibits an 

 acquired variation, special forces must have acted on the 

 organism during its development. 



If we could only trace them back, we should find that 

 all natural characters of living organisms were based on, 

 or in a sense were originally acquired variations ; and our 

 reason for saying so is this : that the evolution of life 

 into being was itself Acquired Variation ; it was variation 

 from the previously existing Inorganic at the call of en- 

 vironmental forces, which were the influences from outside 



