24 



TOXICITY OF SALT CCMBINATICN3 

 CalcJTm , magnesium and potassium * It requires a 

 relatively high concentration of calcium, magnesium or pot- 

 assium nitrate to inhibit the germination of the spores. 

 With Ca(TTC3)2 normal germination was found in C.5m solut- 

 ions and swollen tubes were abundant in C.6m. At a concen- 

 tration of 0.7m, however, none of the spores germinated in 

 any of the fovir series of duplicate cultures which were 

 carried out. The concentration of 03(^03)2 which just pre- 

 vents germination appears then to lie between C.6m and C.7m. 

 Magnesium nitrate is similar to that of calcium in its effect 

 The spores germinated normally at a concentration of C.4m 

 and local swellings of the spore wall and swollen tubes were 

 produced in a 0.5rasolution, while no germination was evident 

 when a 0.6m solution was employed. The concentration at 

 which IvIg(II0J2 just inhibited germination thus seems to lie 

 between 0.5m and 0.6m . In solutions of KNO3 the spores 

 germinated normally in a concentration of 0.9m and germin- 

 ated with local swellings of the spore wall in molecular 

 concentration. As this was the highest concentration used, 

 the point at which KNO3 inhibits germination was not deter- 

 mined. 



The exceedingly high concentrations of these salts 

 which were found nesessary to inhibit germination made it 

 seem possible that they might be without toxic effect upon 

 these spores; the inhibition of germination which was ob- 

 served in high concentrations might have been the result 



