200 



THE BOTANICAL MAGAZINE. 



Vol. xx'vn. n 



From the above table, it is clear that in a mixture of 

 calcium and magnesium ions the toxic effects of these cations 

 were mutually counteracted. The amount of calcium required 

 to antagonize the toxic effect of mngnesium was less than that 

 of the latter to the former, that is to say, as we observed that 

 the highest development of the plants was attained in the 

 mixture of 1/10 N. CaCL 5 cc. + 1/10 N. MgCl 25 cc, con- 

 sequently the antagonizing power of calcium is strong and that 

 of magnesium is weak. 



V. Experiment with NaCl and Wa^SO^ 



In the above four experiments, we examined the antagon- 

 ismus between the metallic ions in regard to their toxic effects 

 upon the growth of rice seedlings. We then undertook to 

 investigate the question of the mutual power of counteracting 

 injurious effects of anion upon the development of rice plants. 

 Hence, sodium chloride and sulphate were selected as salts to 

 be tested and examined in a manner similar to that followed 

 in the case of the experiment with sodium and magnesium 

 chloride. The plants were measured as follows : 



Solutions used 



Length 

 of leaf 



Length 

 of root 



Number 

 of roots 



1/10 N. NaCl 30 cc. 



mm. 



42 



mm. 



30 



1 



1/10 N. NaCl 25 cc. + l/10 N. Na,S(\ 5 cc. 



60 



40 



1 



1/10 K. NaCl 20cc. + l/lO$.Na. 2 S0 4 10 cc. 



53 



30 



1 



1/10 N. NaCl 15cc, + l/10K.Na. 2 SO 4 15 cc. 



42 



30 



1 



1/10 N. NaCl 10 cc. + 1/10 N. Na 2 S0 4 20 cc. 



52 



30 



1 



1/10 N. NaCl 5 cc+1/10 N. Na 2 S0 4 25 cc. 



55 



30 



1 



l/ln N. Na 2 80 4 30 cc. 



45 



35 



1 



Distilled water 30 cc. 



80 



50 



7 



The counteraction observed in this experiment is doubtless 

 due to the actions between the anions (CI' and SO") present 

 in the culture mediums since the cations in both salts are the 



