26 



MACDOUGAL— ACTION OF BASES AND SALTS 



obtained from the salted biocolloid, disregarding- possible osmotic 

 effects, it will be seen that hydration in both potassium and sodium 

 is greater than in water, magnesium equivalent, the swelling less in 

 calcium and acid, indicating that the cell-colloids are dominantly 



TABLE IX. 

 Hydration of Roots of Zca ma'is, Living and Dried, at 15° C. 



pentosans. The dried and dead material showed increased hydra- 

 tion capacity over water in all solutions except that of calcium, 

 measurements which may be taken to be free from the major part 

 of the errors introduced by the osmotic and plasmolytic effects in 

 the living material. It is notable also that when calcium was bal- 

 anced with sodium the swelling was at a minimum in the living 

 material but it rose above that in water in the dried cell-masses, but 

 did not attain the maximum value for the series which was shown 

 by the calcium solution at 0.0002 M. The dried material presents a 

 series of hydration reactions which suggest those of an agar-gelatine 

 mixture. 



The smaller actively growing roots of the same maize plants 

 were subjected to comparative tests in a living condition only. 

 Swelling was most in acid and least in water, the series being water 

 = NaCl, balanced solution, CaClo = KCl, HCl, as contrasted with 

 the larger roots in which the series was CaCl.,, balanced solution, 

 HCl, KCl, and NaCl as given in Table X. 



Seeds furnished by Dr. Fawcett, of the Citrus Experiment Sta- 

 tion at Riverside, California, were sprouted in a chamber at 23° to 

 25° C, by being placed in a moist sand bed. When the roots had 

 attained a length of i to 3 cm. the apical portions 3 or 4 mm. in 



