Feb. 17. I9I9 Effect of Barium and Strontium on Plant Growth 191 



were up, but maintained a struggling existence during the greater part 

 of the time other plants in the series were making a normal growth, thus 

 indicating that strontium carbonate is less toxic in the absence of cal- 

 cium carbonate than barium carbonate. 



Table VIII. — Percentage of nitrogen, protein, phosphorus, and potassium in the grain 

 grown in the pots in the fifth series of experiments 



CORN 



In a sixth series of experiments com plants {Zea mays) were grown in 

 pots of sand containing the usual basal plant-food ration. To these pots 

 were added var^dng amounts of barium and strontium compounds as 

 shown in Table IX. Three com plants were allowed to grow in each pot 

 until the plants had tasseled and bloomed. As was to be expected, the 

 corn plants were dwarfed on account of greenhouse conditions, the plants 

 reaching a height of about 3 feet. After making their maximum growth 

 the stalks were cut from the roots at the top of the sand. The fodder 

 was stripped from the stalks. The roots were taken up and washed as 

 free from adhering sand as possible. The dififerent parts into which the 

 plants were divided were kept separate, and after thoroughly air-drying, 

 the weight of each of the parts determined and from thence the air-dry 

 weights of the entire plants were computed. These results are given in 

 Table IX. 



The results in this series of experiments agree in a general way with 

 those obtained in previous experiments with wheat and oats, where the 

 same compounds of barium and strontium have been applied in equal 

 quantities and under similar conditions. 



