67 



GENERiiL DISCUSSION 



The results of the experiments described in the 

 foregoing pages show that, in certain cases at least, the 

 effect of a toxic salt on the germination of the conidia of 

 Glomerella cingulata may be influenced by the addition of 

 calcivim, magnesium or potassium nitrates .That this effect is 

 not due to depression of ionization of the toxic salt has 

 been demonstrated. That it cannot be due to the formation 

 of xindissociated double salts has been shown for the comb- 

 ination of Cu(NC3)2 with Ca(K03)2 and of ZntNOsJg with cal- 

 cium or magnesium nitrates. The influence of calcii:an upon 

 the toxicity of the salts of the heavy metals here employed 

 must then be related to an effect of the Ca(N03)2 on the 

 spore or to an effect on the contained protoplasm is nade 

 probable from the fact that copper, lead, alximinum and nick- 

 el nitrates sensibly affect the protoplasm in various wajs 

 without producing any apparent changes in the spore wall. 

 If now this antagonistic action of the two salts is to 

 be Belated to the protoplasm of the sppre, the question 

 naturally arises, whether the effect of the salt of the 

 lighter metal, in decreasing the toxicity of the other salt 

 toward the protoplasm may not be related to some 

 specific effect or effects of the salts. 



Loeb^^ has advanced the theory of ion-proteid 

 25. Loeb, J., On ion-proteid compounds and their role in 

 the mechanics of life phenomena. I., The poisonous character 

 of a pure NaCl solution. Am. Journ. of Physiol. 7:327-338. 



