45 



of limo in the ash and dry substance of the plant, and also a marked 

 decrease in the amount of iron in the ash. 



If the plants which have made the best growth have an ash compo- 

 sition nearest the optimum, it would appear from these results as 

 though the diminished growth of the plants most affected on the 

 calcareous soils were due either to (1) an undue increase in the lime 

 content of the plant or plant ash, or (2) an increase in the lime 

 combined with a decrease in the iron in the plant. 



From these results alone it would appear as though the first suppo- 

 sition were correct, but from direct experiments with pineapples the 

 second supposition appears more probable. 



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