816 CONTRIBUTIONS TO OUR KNOWLKDGB OF SOIL-FERTILITY,. 



The Solubility of Toxin in Saline Solutions. 

 Experiment vii. 



Experiment viii. 



Soil No.4. 



1,000 bacteria became 



Extracted with 0-5%NaCl(dist. water) 

 KoSO^,, 



boiled 1 hour 



MsSO 



i " 



Control (NaCl in distilled water) 



88 



9,375 











211,000 



In (vii.) it is seen tliat dilute saline extracts more toxin tlian 

 water, while (viii.) indicates that sodium chloride falls short of 

 potassium and magnesium sulphate. That the lessened bacterial 

 growth was due to toxin, is shown in the following,which was made 

 with the unheated extracts, two days later. The plates smeaied 

 at the start of the experiment were spoilt, and the numbers aie 

 based upon 2o0 cells being in ^^^jcc; this was the average of 

 several experiments made before and after. 



Experiment ix. 



