384 



GRACE MEDES 



explained by the presence of a greater proportion of the sodium 

 in the molecule added. 



The specific effect of the carbonate must be considered to 

 increase the bulk of the skeleton, combined with a strong 

 tendency toward regularity and symmetry. This latter quality 

 is so pronounced that it inhibits completely the opposite tend- 

 ency produced by alkalinity, that is, irregularity and asym- 

 metry. In the stronger carbonate solutions, even in the earliest 

 stages, the retarding and inhibiting effect of the carbonates sup- 

 presses completely any tendency for increased rate of develop- 

 ment that would otherwise occur. 



In the preceding set of experiments, the one in which Na2C03 

 was employed gave some indication of the specific effect of the 

 sodium; but since this is an alkaline salt, the modifications pro- 

 duced by its cation were complicated or completely masked 

 by the greater effects of the anion and of the increasing alkalinity. 



In the following series, neutral salts were employed, NaCl, 

 in a series of iso- and hyper-tonic solutions. 



Experiment H. Plot 13. July 16, 1915 



a ■ Sea-water 



h 90 cc. S. W. + 10 cc. 0.52M NaCl 



c 80 cc. S. W. + 20 cc. 0.52M NaCl 



d 70 cc. S. W. + 30 cc. 0.52M NaCl 



e 60 cc. S. W. + 40 cc. 0.52M NaCl 



/ ; 50 cc. S. W. + 50 cc. 0.52M NaCl 



g 40 cc. S. W. + 60 cc. 0.52M NaCl 



