1918] 



161 



Tabic 27 was computed from the results giveD in table 2. Mag- 

 nesium chloride was present in uniform concentration of .24 M. with 

 varying concentrations of calcium chloride. 



It will be noted that the dry weights with a ratio of magnesium in 

 calcium of 16:1, 8: 1, and 1 : 18 are nearly the same. The ratios of 

 these two elements found in the plants grown in these solutions were 

 2:1. 1:1. 1 : 1.2 for the roots, and 1 : 4.6. 1 : 1.6. 1 : 1.2 for the tops. 

 Further, the dry weight of plants grown in a solution in which the 

 ratio was 41:1 and with a ratio of 1:1 are nearly the same. It is 

 evident that the same ratio for the roots may not hold for the tops. 



Table 28 gives the ratios in the solutions used in series 4. in which 

 the ratios of magnesium to calcium varied from 20.2:1 to 1.7:1. 

 Growth is nearly the same in solutions in which the ratio was L0.5: 1 

 as in those in which the ratio is 3.4:1 or 2.5:1. The plants grown 

 in these cultures gave the following values for the tops: 5.4: 1. 3.4: 1. 

 2.5: 1. and for the roots, 4.7: 1. 4.1:1, and 2.8: 1. There is a tendency 

 for the ratio of calcium to magnesium in the plants to become narrower 



