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Annual Be port of the 
partly through the soil and roots. The remainder is dissolved out 
of mineral matter furnished by the rocks, either in its compound 
condition, or subsequently formed in the soil out of its free ele¬ 
ments. In the relation here established between the soil and the 
plant, nature furnishes us with the following facts that we should 
remember in all our processes of culture. 
1. No plant can live upon the uncompounded elements of nature. 
These elements must be formed into certain definite compounds by 
chemical forces, before they can be used as plant-food. 
2. No plant can live upon solid matter. These compounds must 
be dissolved in a fluid before they are in a condition to be taken up 
by the thread like fibers of the root, and to enter the cellular struc¬ 
ture of the plant. These absolute conditions of matter in the soil 
necessitates certain forms of force there; as do also the germination 
and growth of plants. In confirmation of this, let us look for a 
moment at a growing plant. Here we notice not only form but 
force; that is, we notice not only matter entering into its composi¬ 
tion, but a manipulation of force by which it grows and developes. 
Now inasmuch as a plant cannot create a particle of the matter of 
which it is formed, neither can it create a particle of the force by 
which it grows. We have just seen where the matter comes from. 
Whence the force? Let us turn our attention in this direction for 
a moment. 
At the beginning of this paper I noticed the fact that, no sooner 
is new-made rock lifted up into the atmosphere than the work of 
disentegration commences. That these disintegrating and dissolv¬ 
ing forces are of atmospheric origin, I think there can be no doubt. 
And in the fully developed soil, it is to the free circulation of at¬ 
mospheric air more than to any other cause that we are indebted 
for those physical and chemical forces, without which soil and plant 
formation cannot be-carried on. It acts not only upon the rocks, 
the mineral matter upon which the soil rests, and of which it is 
partly formed, but upon the decaying animal and vegetable remains 
with which it is continually replenished. 
I have stated that near nine-tenths of the matter entering into 
plant-formation, enters as carbonic acid and water. But before tak¬ 
ing their places in the structure of the plant, these compounds are 
decomposed in the leaves by the action of sunlight, the carbon of 
the acid and the hydrogen of the water only are used in building 
