248 



BOTANICAL GAZETTE 



[SEPTEMBER 



cultures, that is, into the groups mainly phosphatic, mainly nitroge- 

 nous, and mainly potassic. 



TABLE II 



Showing the effect of the mainly phosphatic, mainly nitrogenous, and mainly 



potassic fertilizers on cumarin 



Phosphate as disodium phosphate 



Fertilizers composed of 50 to 



ioo per cent op 



Green weight 



Normal 



With 10 p.p.ra. 

 cumarin 



Phosphate 

 Nitrate . . , 

 Potash. . . 



grams 

 36.3 



45- 8 

 445 



grams 



34- 1 



403 

 38.2 



Relative growth (normal 



= 100) 



94 

 88 



86 



Here again the effect of the mainly phosphatic fertilizers is 

 the same as with the monobasic salts already discussed, although 

 this effect is not as marked in this experiment. There remains 

 the trisodium phosphate of alkaline reaction to be studied in this 

 regard. 



Effect of trisodium phosphate 



The plants in this experiment grew from November 29 to 

 December 10 and the results are given in table III. 



TABLE III 



Showing the effect of the mainly phosphatic, mainly nitrogenous, and mainly 



potassic fertilizers on cumarin 



Phosphate as trisodium phosphate 





Fertilizers composed of 50 to 



100 per cent of 



Green weight 





Normal 



With iopp.m 

 cumarin 



Relative growth (normal 



= 100) 



Phosphate 

 Nitrate. . . 

 Potash . . . 



grams 

 37-0 



42.4 

 42-9 



grams 



33-9 

 34-6 



3 l 7 





91 

 81 



74 



These figures show that the effect of this alkaline reacting 

 tribasic phosphate has the same effect in overcoming the toxic 

 action of the cumarin as had the calcium acid phosphate, the 



