302 ACTIONS OF AKTIFICIAL MANURES 



changed. To verify these observations various water cultures 

 were started in which vigorous growth was maintained for 

 some months, at the end of which time analyses were made 

 both of the plants and of the liquid. The results all confirmed 

 the older observations and the deductions that can be made 

 from the composition of the crops from the field : the culture 

 solution, which represents the soil, become more alkaline as 

 growth proceeds (or in the majority of cases less acid, because 

 for the success of the water culture it is desirable to start with 



TABLE CI. Acids and Bases in Crops reduced to Equivalents. 



the solution somewhat acid), and the greater the growth the 

 greater the amount of base left in the solution. In one 

 example, details of which are quoted in the original paper 

 (loc. cit.), wheat was grown in the same jar of solution from 

 3rd March until llth June, until grain was fully formed and 

 the plants had reached the weight of $37 grams ; by this time 

 the solution had acquired an excess of bases equal to about 

 25 per cent, of the total present, while the plant contained a 

 corresponding excess of acids. Thus two distinct lines of 

 evidence agreed in assigning the production of alkali in the 



