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. 



