INORGANIC CONSTITUENTS. 



11 



This procedure, which prevented the absorption of most of the 

 readily soluble salts of the ungerminated seeds by the growing seed- 

 lings, was followed in the subsequent work. Not only were the seeds 

 given a previous steeping but the solutions in which the seedlings 

 grew were changed more frequently. 



AMOUNTS QP PLANT FOOD REMAINING IN THE SEED. 



Figure 2 shows the amounts of nitrogen, phosphoric acid, and potash 

 left in the seed at intervals during a period of 12 days and the dry 

 weight of the seed at the corresponding dates. It emphasizes how 



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Fig. 2.— Graph showing decreasing weight of seed and loss of inorganic plant constituents therein. 



fast the potash of the aeed is depleted, the amount left in the seed 

 at the end of 12 days being only 4 per cent of the original quantity, 

 while in the case of nitrogen and phosphoric acid 17 and 20 per cent, 

 respectively, remain. 



At the end of 17 days the seeds contained only about 4 per cent of 

 the original amounts of nitrogen, of phosphoric acid, and of potash; 

 the report of the Microchemical Laboratory stated that the residual 

 seed consisted of a mass of disorganized aleurone layers and bran, 

 the cells appearing to be empty except for globules of oil. If platted 

 at this period, and subsequently thereto, the curve would have 



