fil2 CONTKIBUTIONS TO OUR KNOWLEDGE OF SOIL-FERTILITY, iii. 



In conclusion, we have seen that, from soil, there can be 

 obtained a water- soluble, alcohol-insoluble substance which we 

 call a gum, and that this, upon hydrolysis, is converted into a 

 mixture of dextrose, galactose, and another sugar. The presence 

 of galactan is a strong indication that the gum has had a bacte- 

 rial origin, and there is every likelihood of the soil containing 

 bacterial slimes. These are always nitrogenous, and will have an 

 inliuence among the many factors that constitute soil-fertility. 



