THH INFLUiNC3 OF CALCIUM, I.IAGNESI UI.'. aND P0TASSIUI4 NITRATES 

 UPON TH2 TOXICITY OF CERTAIN EEA^TY I'.ETALS 

 TOWARD FUNGUS SPORES. 



ABSTRACT 



This study has to do with the influence of one salt 

 upon the toxic effect of another upon fungus spores. It is 

 shown that the toxic effect of Cu(N03)2 on the germination 

 of Gloeosporium spores can be inhibited or modified by the 

 addition to the medium of Ca(N03)2 and that the molecular 

 ratio of the quantity of Ca(NC2)2 thus required to the am- 

 ount of CuCNCgjg present increases with the concentration 

 of the latter. This effect is apparently the result of a 

 simultaneous action of the two salts upon the organism and 

 cannot in cases here considered be related either to form- 

 ation of an undissociated double salt or to depression of 

 the ionization of the toxic salt because of the ion common 

 to the two salts. Potassium nitrate is also effective in 

 inhibiting or modifying the toxicity of Cu(NC3)2. I'he in- 

 fluence of calcium upon the toxicity of copper is of inter- 

 est in the problem of fungicides and fungicidal action. 



The toxicity of Pb(NC3)2 is similarly influenced 

 by the presence of Ca(NC3)2 and the ratio of the calcium 

 salt to that of lead was found to be constant fot the three 

 different concentrations of the toxic salt that were employed. 

 The toxicity of this lead salt is likewise influenced by 

 proper concentrations of l.:g(NC3)2. goth Ca(N03)2 and 



