V8 PLANT LIFE ON THE FARM. 
first season of growth, the leaves collect and form the 
nutritive matters which are subsequently transferred to 
the “root,” and the store so accumulated is utilized the 
following season in the formation of flowers and seeds, as 
before explained. 
Growth, then, in a chemical sense, may be said to con- 
sist in the absorption of the raw materials for the food of 
plants—development, in a chemical sense, may be taken 
as including the various transformations which those 
raw materials undergo to fit them for the nutrition of 
the plant, or the formation of reserve-materials to be 
stored up for future use. The history of these develop- 
mental changes is a matter for the chemist to clear up 
with the aid of chemical re-agents, used both with and 
without the help of the microscope. It is in this de- 
partment of physiology that our knowledge is at present 
most imperfect. 
Maturation.—The foregoing facts and phenomena have 
been brought to light principally by chemical analysis of 
the same kind of plant at different times and in different 
stages of its growth, and particularly by the analysis of 
different parts of the same plant, some young, some old. 
In the case gf wheat, it was ascertained by Messrs. Lawes 
and Gilbert that during the five weeks beginning with 
June 21, there was but little accumulation of nitrogen in 
the plant, while during the same period more than half 
the total carbon was accumulated. The building-up 
process was thus going on more quickly than that of 
maturation. In this manner it has also been found, not 
only that the starchy and the albuminous matters under-- 
go changes and disappear from the leaves, but that 
mineral matters and salts, such as phosphates and salts 
of potash, which at one stage of growth abound in the 
leaves, at; another time are almost entirely absent from 
them, but are found in abundance elsewhere, The mi- 
