7 6 



U. SUZUKI. 



2) RUBUS IDAEUS L. VAR. STRIGASUS MAXIM. 



The experiment was carried on exactlj' in the same way as 

 with Phlox paniculata. But in this case, control experiment was 

 also made with distilled water. The result was almost the same 

 as in the former experiment, the only difference was that the Sr 

 plants suffered most. They died already on the 24th and no leaf 

 remained alive until the 27th, all having turned brownish black. 

 The Ba plants also died, and nothing remained until the 24th. 

 The Ca and control plants were quite healthy until the end of 

 the experiment and no difference was observed between them. 

 The Ca + Sr and Ca + Ba plants also remained alive until the 

 end of the experiment (1st May), but by this time the edges of 

 the leaves turned brownish black. 



3) Coreopsis tinctoria Nutl. 



The same experiment was repeated with the young plants 

 of this species having roots, and the same result as above was 

 obtained. The Ca and control plants were the best; the Ca + Sr 

 and Ca + Ba plants were also very good ; but toward the end of 

 the experiment (1st May) they began to show signs of suffering. 

 The Sr and Ba plants, on the contrary, began to suffer already 

 on the 24th, being unable to stand upright, and the leaves, with 

 the exception of those on the upper part of the stems, nearly all 

 dying off by the end of the experiment. 



The above five experiments are enough to prove that 

 strontium and barium salts are strongly poisonous to the higher 

 plants and can never replace calcium salts. Their poisonous 

 action can, however, be neutralized to a large extent in the 

 presence of lime salts. In the experiment with Rubus and 

 Coreopsis we observe that control plants, kept in distilled water, 

 were equally healthy ; so it is quite evident that the bad 

 condition of the Sr and Ba plants in these species was due not to 

 deficiency of the necessary lime salts, but to the poisonous action 

 of strontium and barium salts. If the principal function of lime 

 salts consists merely in neutralizing the oxalic acid formed 

 during metabolism in the plant cells, and if it never enters into 

 closer combination with the protoplasm, then we must have 

 naturally quite different results from those above obtained ! 



