10 Hydration and Growth. 



vary widely, but still absorb water. A correct delineation of the man- 

 ner in which osmosis and imbibition interlock in growth is one of the 

 tasks demanding the immediate attention of the physiologist. 



It has been assumed in the present work that when the chief con- 

 stituents of protoplasm are brought together in a colloidal condition, 

 approximating that of hving matter, the behavior of this material would 

 furnish data fundamental to the physics of growth. The justification 

 for this assumption is to be found in the following pages, in which are 

 described the reactions of biocoUoids, of dead sections, and of organs 

 of living plants in hydration and growth as affected by solutions, cul- 

 ture media, the products of metabolism, and environmental agencies, 

 especially temperature. 



