30 MACDOUGAL— ACTION OF BASES AND SALTS 



10. Different ecological types of roots of maize show different 

 hydration reactions to the solutions used in hydration tests of col- 

 loids as noted in the foregoing paragraphs. 



11. Roots of strawberry show differing hydration reactions when 

 grown in saline soils and in sand. 



12. Roots of orange seedlings show lessened hydration in acid 

 solutions and their hydration was lessened in all solutions except 

 balanced solutions of sea-water and of sodium and calcium chloride. 



13. Swellings of sections of joints of Opuntia were greatest in 

 KOH at o.oi A^, HCl at o.ooi N and KCl at o.oooi M, all produc- 

 ing effects in excess of the swelling in water. 



14. The changes in volume of living cell-masses in hydrating 

 solutions include osmotic-plasmolytic eft"ects in the alterations of 

 the volume of the included cells. The hydration of dead cell-masses 

 includes possible osmotic action of cell-walls. 



15. The hydration reactions described in this paper may include 

 coagulation effects when the higher concentrations were applied to 

 the biocolloids, similar to those of the plasmatic colloids. Actual 

 effects of balanced solutions are clearly defined in the hydration of 

 agar, and some suggestions of similar action in the biocolloids arise 

 from the measurements of swelling of the biocolloids described. 



