DIFFERENTIAL GROWTH 183 



data and then proceed to mix into their description and interpretation 

 such vague terminology as this. The mixture can be no more precise 

 than its vaguest ingredient. To deal with growth as an entity, which can 

 be "activated," "stimulated," "retarded," or "suppressed," is only part 

 science, and for the other part, fiction. The less we let our work and 

 thoughts be misled by the delusion that "growth" is basically but a 

 simple elementary process, like a "bimolecular reaction," the faster will 

 be our progress toward true insight into the real mechanisms of devel- 

 opment. To promote this more factual approach to the problem of 

 growth, I have tried in this sketchy survey to portray the problem in its 

 natural complexity. If the discussion has helped to make clear what the 

 problems are, it will have served its purpose, even if some of the special 

 interpretations and hypotheses presented may not stand the test of time. 



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