Development of Roots of Agricultural Plants. 423 
for the infant growth.* In those cases in which there is no albumen 
whatever, some little soluble matter may be derived from the in- 
teguments which may conduce to the change from a state of perfect 
rest to one of active growth ; and by means of this, chemical 
change may take place in matters stored up in the cotyledons 
themselves, which may aid in the primary development of the 
embryo. 
Supposing, then, moisture, warmth, and air to be ready in their 
proper measure, the water is absorbed by the integuments, from 
thence by the albumen if present, and finally by the substance of the 
embryo. The water converts soluble fibrine into diastase, which 
in its turn acts upon the starch, converting it into sugar, which is 
also supplied by the oil globules, which are sometimes abundant, 
while other portions are converted into dextrine, and the cellulose 
itself undergoes chemical changes which in the end tend to the 
evolution of the embryo, or to its nourishment during the early 
stages of growth ; and sometimes one nitrogenous matter acts upon 
another, and so induces change. The oxygen of the air which is 
in contact with the seed combines with part of the carbon, and 
carbonic acid is evolved, and at the same time a notable quantity 
of acetic acid. In fact, the seed is a miniature laboratory, in 
which numerous chemical actions are taking place, many of 
which would defy our powers of manipulation. 
Where these conditions are not combined, either germination 
is suspended, or the seed finally rots or withers. Each seed has 
its own range of temperature, within which alone germination 
can take place, and a limited period beyond which its vitality 
cannot be preserved. Carefully conducted experiments do not 
confirm the marvellous accounts which are from time to time 
brought forward respecting the suspension of germination for 
many centuries. Such accurate observers as the late Professor 
Henslow, without any proclivity to the marvellous, have effec- 
tually dissipated numerous histories in this direction which have 
too unguardedly been received as true. 
As the radicle is the first to break its bonds, it will be nourished 
after a short time directly from matters either traversing the 
pores of the soil, or combined with it, and will profit only indi- 
rectly by any nutritive matter which may yet remain in the 
albumen or cotyledons, its own efforts being now indeed mainly 
* Plants grown in pure water without any addition to it of mineral substances 
acquire no increase in weight beyond that of the seed from whence they are 
derived, and can bring no fruit to perfection, even if they form flowers. It 
appears from Boussingault's experiments, that where mineral substances are ex- 
cluded, the organs will absorb water, but neither carbonic acid nor ammonia ; or at 
least, even though they be introduced into the plant by means of the water, they 
exert no influence upon the internal process : they sutler no decomposition, and 
no vegetable matter is formed from their element. — Liebig, 1. c. p. 44. 
