THE LIFE CYCLE 367 



turned to profit their ability to call forth plant growths in 

 excess of the normal. We have already noted how often 

 galls are fruit -like in form (fig. 214). The cone gall of the 

 willow (fig. 203) is not a deformed shoot, but an overgrowth 

 (hypertrophy) of tissue superadded to the normal growth 

 of the shoot. 



Organic harmony. Whether an organism develop out of 

 an egg under normal or under artificially altered circum- 

 stances, whether out of a piece of a pre-existing organisms or 

 out of pieces of two put together, if it develop at all it is 

 pretty sure to develop with organic unity, with symmetry 

 and proportion. Its dominant tendency is toward organic 

 wholeness. 



FIG. 214. A pod -like bud gallon Pistachia (after Kerner and Olivier) show- 

 ing response to external stimulus. 



