324 HOW CROPS GROW. 
Of the elements that assume the gaseous condition, ca: 
bon does so to the greatest extent. It unites with atmos- 
pheric oxygen (partly with the oxygen of the seed, ac- 
cording to Oudemans) producing carbonic acid gas (CO,,.) 
Hydrogen is likewise separated, partly in union with 
oxygen, as water (H,O), but tu some degree in the free 
state. ree nitrogen appears in considerable amount, 
(Schulz, Jour. fiir Prukt. Chem., 87, p. 163,) while very 
minute quantities of Hydrogen and of Nitrogen combine 
to gaseous ammonia (NH,.) 
Heat developed in Germination. — These chemical 
changes, like all processes of oxidation, are accompanied 
with the production of heat. The elevation of tempera- 
ture may be imperceptible in the germination of a single 
seed, but it nevertheless occurs, and is doubtless of much 
importance in favoring the life of the young plant. The 
heaps of sprouting grain seen in the malt-house warm so 
rapidly and to such an extent, that much care is requisite 
to regulate the process; otherwise the malt is damaged by 
over-heating. 
2. The Transfer of the Nutriment of the Seedling 
from the cotyledons or endosperm where it has undergone 
solution, takes place through the medium of the water 
which the seed absorbs so largely at first. This water 
fills the cells of the seed, and, dissolving their contents, 
carries them into the young plant as rapidly as they are 
required. The path of their transfer lies through the 
point where the embryo is attached to the cotyledons ; 
thence they are distributed at first chiefly downwards inte 
the extending radicles, after a little while both down- 
wards and upwards toward the extremities of the seedling, 
Sachs has observed that the carbohydrates (sugar and 
dextrin) occupy. the cellular tissue of the rind and pith, 
which are penetrated by numerous air-passages; while at 
first the albuminoids chiefly diffuse themselves through — 
