22 



Hydration and Growth. 



The greatest capacities for hydration encountered were those in 

 which plant proteins, such as those of oats, were added to agar in the 

 proportion of about 1 in 10, a ratio which finds its equivalent in the 

 constitution of many of the higher plants. The maxima exhibited by 

 such mixtures are not duphcated by the plant, in which the presence of 

 salts in the colloids and the morphological structure operate to limit 

 the amplitude of the swelling. 



Table 3. 



The method of admixture of the carbohydrate-protein-saline con- 

 stituents of the biocoUoids consisted mainly in the use of temperatures 

 which would bring all of the substances into a liquid condition in which 

 they might be as intimately united as possible, and the plates formed 

 appeared translucent but uniform throughout, although it is not to be 

 assumed that the components in this case or in any preparation, or in 

 protoplasm, are mutually interdiffused. It seemed desirable to attempt 

 to make mixtures in which the carbohydrate-protein elements would 

 be less intimately united, and to that end some simple experiments 

 with powdered agar and powdered gelatine were carried out. 



Powdered gelatine and agar which would pass the millimeter mesh 

 of a screen were used to ascertain what degree of expansion would be 

 registered on the auxograph when these were simply placed in a layer 

 in the dish and subjected to the action of solutions. Whatever the 

 arrangement of the material in these particles, their separate action 

 in swelling and in dispersion or solution would be free from the action 

 resulting from structures such as those presented by plates held rigidly 



