214 THE PROBLEMS OF EVOLUTION 



part undergoes change, adjustments must be made 

 elsewhere in the body. It is conceivable that 

 through gradual development a character might 

 ultimately attain a condition of sufficient impor- 

 tance, or a condition sufficiently different from 

 that in which it existed at an earlier stage, that 

 the body, in spite of the cessation of the original 

 stimulus, could not return the character suddenly 

 to its original condition, but must gradually work 

 out an adjustment according to the importance of 

 the internal relationships involved. 



It is not necessary to limit our analysis of ac- 

 quired characters to this one possible method of 

 perpetuation. While it is conceivable that an 

 organ may attain a degree of importance which 

 would guarantee its persistence beyond its period 

 of active usefulness and make its loss impossible 

 save through the gradual reduction which we 

 ascribe to our own vestigial structures, its develop- 

 ment may also give rise to new environmental 

 associations. Any association with an additional 

 environmental condition would bring new stimuli 

 to bear on its further development, and would also 

 open the possibility of perpetuation of the charac- 

 ter through selection. The latter point is the essen- 

 tial feature of Cuenot's idea of preadaptation, 

 although he does not extend his theory to the 

 origin of the character in the beginning. Any such 

 shift in environmental relations must certainly add 



