40 EXPEKIMEXT STATTOX. [Jan. 



the point of view of Y)]i\ut food containcMJ it is more expensive 

 than most chemical fertilizers. Still, we believe that no chem- 

 ical fertilizer can take its place on lawns. The nniiihcr of weed 

 seeds it contains is its worst feature, but this iniiiht possiltly ])e 

 overcome by some system of sterilization.^ The ap[)lication of 

 steam v.'ould have a tendency to increase the ammonification 

 and wonld be a troublesome prcx^ess, but if the weed seeds conld 

 ])e kille(l by an a])])lication of formaldehyde and potassium per- 

 manganate it would V)e a practical method. Fumigation with 

 this substance will kill onion seed very quickly, l)Ut whether it 

 would have the same effect on weed seeds we do not know. 



» Some brands of pulverized sheep manure are said to be sterilized. 



