Chapter VIII 



GROWTH MEASUREMENTS AND THEIR 

 INTERPRETATION 



The chief aims of plant tissue cultures are, of 

 course, first, the setting up of a group of condi- 

 tions which shall adequately duplicate those under 

 which the organ, tissue, or cell lives in nature, in 

 such a manner that its behavior therein is quanti- 

 tatively and qualitatively "normal," that is simi- 

 lar to what it would have been in its native 

 environment ; and, second, the study of the quanti- 

 tative and qualitative changes which take place 

 in its behavior when single elements of these con- 

 ditions are altered. This gives us a measure of 

 the importance and function of each character- 

 istic of the environment in the economy of the 

 organ, tissue, or cell under investigation, permits 

 us to sort out the significant from the merely for- 

 tuitous elements of behavior, thus simplifying our 

 picture of the real organism, and should lead to 

 a better understanding of behavior itself. 



Qualitative differences cannot easily be repre- 

 sented except by descriptive — hence subjective — 

 means. These must inevitably fall short of the 



