242 RECAPITULATION 



type in classification exhibits a combination of the 

 two. To assert that all characters are adaptive is as 

 erroneous as to state that all characters are blasto- 

 genic mutations, and therefore in their origin non- 

 adaptive. 



9. Finally it may be urged, although the question 

 has not been directly discussed in this volume, that 

 no biologist is justified in the present state of know- 

 ledge in dogmatically teaching the lay public that 

 gametogenic characters are alone worthy of attention 

 in questions of eugenics and sociology. Hereditary 

 or constitutional factors are of course of the highest 

 importance, but there exists very good evidence that 

 modifications due to external stimulus do not perish 

 with the individual, but are in some degree handed 

 on to succeeding generations, and that good qualities 

 and improvement of the race are not exclusively 

 due to mutations which are entirely independent of 

 external stimuli and functional activity. It is 

 important to produce good stock, but it is also 

 necessary to exercise and develop the moral, mental, 

 and physical qualities of that stock, not merely for 

 the benefit of the individual, but for the benefit of 

 succeeding generations and to prevent degeneration. 



