COLLOIDAL BEHAVIOR OF PLANT PROTOPLASM. 



163 



metais are not definitely known, and further complications may arise 

 in the different solubility and behavior of the carbonates which nat- 

 urally are always formed in spite of frequent renewals of the solu- 

 tions. The series of tests which were made to secure information 

 on this matter yielded the following results : 



TABLE IX. 



Swelling of Agar in Alkaline Hydroxides in Percentages of Original 



Thickness. 



The conversion of the data in Table IX. to terms of swelling in 

 water results in the following data : 



TABLE X. 



Swelung of Dried Agar Plates at 15° C. in Solutions of x\lkaline Earth 

 Hydroxides which were Renewed Every 12 Hours. 



Thickness of dried plates in Ba(0H)o and Ca(OH). series 0.14 mm., 

 in Sr(OH)n series 0.16 mm. Total swelling in water 3,03S per cent. 



It is seen that even at the greater attenuations, barium and stron- 

 tium hydroxides limited hydration. As it appeared important to 

 test the favorable effect of calcium solutions of various concentra- 

 tions, a detailed series of tests was carried out. The actual in- 

 creases in percentages of original thickness are given in the upper 

 line of the table below and the values as compared with water as 100 

 in the line below. 



