388 Ever-sporting Varieties 



parent abnormalities, which may occur in the 

 experiments. 



We now may take a broader view of the pe- 

 riod of sensibility. Evidently the response to 

 external influences will be greater the younger 

 the organ. Sensibility will gradually diminish, 

 and the phenomena observed in the last part 

 of this period may be considered as the last re- 

 mainder of a reaction which previously must 

 have been much stronger and much readier, pro- 

 viding that it would be possible to isolate them 

 from, and contrast them with, the other re- 

 sponses of the same plant. 



With the light thus cast upon the question, 

 we may conclude that the sensitive period com- 

 mences not only at the beginning of the germi- 

 nation, but must also be considered to include 

 the life of the seed itself. From the moment 

 of fertilization and the formation of the 

 young embryo the development must be sub- 

 jected to the influence of external agencies 

 which determine the direction it will take and 

 the degree of development it will finally be able 

 to acquire. Probably the time of growth of 

 the embryo and of the ripening of the seed 

 correspond exactly to the period of highest 

 sensibility. This period is only interrupted 

 during the resting stage of the seed, to be re- 

 peated in germination. Afterwards the sensi- 



