270 HOW CROPS GRuW. 
The following statement exhibits the Average Daily In- 
crease of Carbon, Hydrogen, Oxygen, Nitrogen, and Ash, 
(in Ibs. per acre) during the several periods, 
TABLE X.—Br. 
Carbon. Hydrogen. Oxygen. Nitrogen. Ash. 
{st Period, 8.438 1.18 6.30 0.65 1.56 
3d + 66.95 8.94 48.06 3.30 6.55 
4th “ 23.84 2.95 24.06 147 1.44 
apitie C8 39.85 3.89 42.44 1.04 5.23 
Turning now to Arendt’s results, which are carried more 
‘nto detail than those of Bretschneider, we will notice 
A.—The Relative (percentage) Composition of the 
Entire Plant and of its Parts* during the several periods 
of vegetation. 
1, Fiber + is found in greatest relative quantity—40° |,— 
in the lower joints of the stem, and from the time when 
the grain “ heads out,” to the period of bloom. Relatively 
considered, there occur great variations in the same part 
of the plant at different stages of growth. Thus, in the 
ear, which contains the least fiber, the quantity of this 
substance regularly diminishes, not absolutely, but only 
relatively, as the plant becomes older, sinking from 27°|,, 
at heading, to 12°|,, at maturity. In the leaves, which, as 
regards fiber, stand intermediate between the stem and 
ear, this substance ranges from 22°|, to 38°|, Previous 
to blossom, the upper leaves, afterwards the lower leaves, 
are the richest in fiber. In the lower leaves the maximum, 
* Arendt selected large and well-developed plants, divided them into six parts. 
und analyzed each part separately. His divisions of the plants were 1, the three 
lowest joints of the stem; 2, the two middle joints; 8, the upper joint; 4, the 
three lowest leaves; 5, the two upper leaves; 6, the ear. The stems were cut 
just above the nodes, the leaves included the sheaths, the ears were stripped from 
the stem. Arendt rejected all plants which were not perfect when gathered. 
When neariy ripe, the cereals, as is well known, often lose one or more of their 
lower leaves. For the numerous analyses on which these conclusions are based 
we must refer to the original. 
1 i. e., Crude cellulose ; see p. 60. 
