208 HOW CROPS GROW. 
Relative Quantities of Carbon, Hydrogen, Oxygen, , 
and Nitrogen, in dry substance, after deducting the some- 
what variable amount of ash, (per cent). 
TaBLe VII.—Br. 
Carbon. Hydrogen. Ouygen. Nitrogen. 
Ast Period, 50.55 6.81 88.71 3.93 
3d “ 51.85 6.95 38,24 2.86 
4th 50.55 6.96 39.83 2.93 
5th * 49.59 6.21 41,64 2.56 
5.—The Tables V, VI, and VII, 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 nitrogen 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 behind that of Carbon, Hydro- 
gen, and Oxygen. Still otherwise expressed, the plant as it 
approaches maturity organizes relatively more amyloids 
and relatively less albuminoids, 
The relations just indicated appear more plainly when 
we compare the 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. 
Taste VIII.—Br. 
Carbon. Nitrogen. Hydrogen. Oxygen. 
1st Period, 100 18 13.4 73.6 
3d se 100 4.9 13.3 72.5 
4th “ 100 6.1 12.3 100.8 
Sth =“ 100 2.6 10.6 106.5 
From Table VIII we see that the ratio of Hydrogen to 
Carbon regularly diminishes as the plant matures; that of 
Nitrogen falls greatly from the infancy of the plant to the 
period of full bloom, then strikingly increases during the 
