212 
HOW CROPS GROW. 
hand, examined all the plants of a given plot, large and 
small, perfect and inju 
has been already insi 
of the plant is greatly 
red. The differences illustrate what 
sted on, viz., that the development 
modified by the circumstances of its 
growth, not only in reference to its external figure, but also 
as regards its chemical composition. 
The relative distribution of nitrogen in the parts of the 
plant at the end of the several periods is exhibited by the 
following table, simple inspection of which shows the fluc- 
tuations, (relative,) in 
the content of this element. The 
percentages are arranged for each period separately, pro- 
ceeding from the high 
est to the lowest: 
PERIODS. 
I. II. IIL. IV. Vv. 
Upper leaves. Lower leaves. Upper leaves. Ears. Ears. 
3.74 2.39 2.27 2.85 3.04 
Lower leaves. Upper leaves. Lower leaves. Upper leaves. Upper leaves. 
3.38 2.19 2.18 LOL 1,74 
Lower leaves, Ears. Ears. Lower leaves. Upper stem, 
2.15 2.06 1.85 1.62 1.56 
Middle stem. Upper stem. Upper stem. Lower leaves, 
1.52 1.34 1.60 1.43 
Upper stem. Middle stem. Middle stem. Middle stem. 
0.87 0.98 1.20 1.17 
Lower stem. Lower stem. Lower stem. Lower stem. 
0.80 0.88 0.83 0.79 
5. Ash.—The agreem 
ent of the percentages of ash in the 
entire plant, in corresponding periods of the growth of the 
oat, in the independen 
Arendt is remarkably 
below. 
t examinations of Bretschneider and 
close, as appears from the figures 
\ 
PERIODS, 
L IL. III. IV. Ves 
Bretschneider...... 8.57 5.96 5.33 5.40 
Arendt...,.........8.03 5.24 5.44 5.20 5.17 
The diminution at the 2d, increase at the 3d, and sub- 
sequent diminution at 
parallel in both cases, 
the 4th period, are observed to run 
As regards the several parts of the plant, it was found 
