COMPOSITIOH IN SUCCESSIVE STAGES. 227 



Relative Quantities of Carbon, Hydrogen, Oxy- 

 gen, Nitrogen (Organic Matter) and Ash in the dry 

 oat-crop, at the end of the several periods (jper cent) : 



Table WL.—Bretachneider. 



Relative Quantities of Carbon, Hydrogen, Oxy- 

 gen, and Nitrogen, in dry substance, after deducting 

 the somewhat variable amount of ash {per cent) : 

 Table 'VlU.—Sretschneider. 



5. The Tables V, VI, VII, aud VIII, demonstrate that 

 ■while the absolute quantities of the elements of the dry 

 oat-plant continually increase to the time of ripening, 

 they do not increase in the same proportion. In other 

 words, the plant requires, so to speak, a change of diet 

 as it advances in growth. They further show that nitro- 

 gen and ash are relatively more abundant in the young 

 than in the mature plant ; in other words, the rate of 

 assimilation of Nitrogen and fixed ingredients falls be- 

 hind that of Carbon, Hydrogen, and Oxygen. Still oth- 

 erwise expressed, the plant as it approaches maturity 

 organizes relatively more carbhydrates and less albu- 

 minoids. 



The relations just indicated appear more plainly when 

 we compare tJie Quantities of Nitrogen, Hydrogen, and 

 Oxygen, assimilated during each period, calculated upon 

 the amount of Carbon assimilated in the same time and 

 assumed at 100. 



