Abnormal Growth 299 



about abnormal growth but that students of morphogenesis have not as 

 yet made very much use of it for their purposes. Three facts, however, 

 which emerge from a study of this subject have already proved to be 

 of much morphogenetic significance: 



1. The actual developmental potencies of most plant cells are far 

 wider than ever come to expression in normal development. 



2. It is possible to break down the organization of the plant body into a 

 series of successively lower levels and then to restore normal organiza- 

 tion again. 



3. This can be done without modifying the genetic character of the 



cells. 



A continued study of these facts, and of others in this field, will cer- 

 tainly prove very fruitful. Abnormal development is only development 

 under unusual conditions, and the wider spectrum of morphogenetic 

 information thus made available provides the student of development 

 with a powerful tool for the study of some of his most difficult problems. 



