230 
GARDENING AS A SCIENCE, 
It has always been supposed that the decay of vegetable matter within the 
soil was the precursor of vegetable nutriment ; in a word, that it prepared the 
crude sap, and contained all the elements of the vegetable structure. It has, 
however, been the glory of modern science to prove that not a particle of decaying 
matter is taken from the soil: on the contrary, that vegetable substances — humus 
and the base of carbon^ are constantly added to, and accumulated in, ground under 
eroj). 
A writer, (Dr. Fownes,) author of the Prize Essay on the Food of Plants — 
in the Journal of the Eoyal Agricultural Society — thus expresses himself: the 
quotation is substantially the theory of Liebig : — 
" Examine the soil in which trees grow from year to year,^** (as, for instance, in 
a pine forest of barren sand, like that of the Landes of Bordeaux,) " and note its 
constantly increasing richness in humus — in vegetable matter. Far from 
exhausting the soil in this respect, these trees pour out constantly from their 
rootlets matter containing carbon, which, by decay in the soil, becomes humus. 
The dead leaves, and small branches accidentally broken by the wind, accumulate 
beneath and add to this store of humus" — whence did these trees obtain their 
carbon ? The earth did not yield it : it must have been the air. 
" To ascribe the origin of the carbon of plants in a state of nature to the 
absorption of humus from the soil in which they grow, is about as reasonable as to 
suppose the possibility of a race of animals subsisting on their own offspring. 
That substance is a product of the decay of previously existing plants^ and which 
must have got their carbon from some other source. Its quantity, moreover, 
increases every year ; and if this latter fact is not true with respect to some 
cultivated soils, it is easy to see the reason in the greatly accelerated destruction of 
the substance by the oxygen of the air, brought about by the constant loosening 
of the soil ; add to this the slight degree of solubility possessed by humus itself, 
or of the so-called ' humate of lime,' and it is easy to see its total inadequacy to 
supply even a small part of the carbon fixed in a growing plant," 
Enough of quotation to prove the advance of science ; but our authorities yet 
lack an active operating first cause ; they neglect, or do not perceive, the boundless 
energy of the elementary fluid, termed electricity, the bond of all chemical union — 
the agent of all attraction, and of gravitation itself. We shall show this more 
clearly in our closing article on Manures : but in our present position it may 
suffice to state that the crude sap contains all those substances which are directly 
soluble in water — that is to say, the salts of all kinds which are found, either 
simple or compounded, with acids, having alkaline or earthy bases. 
Carbon can only enter the roots in the form of carbonic acid, or of some hydro- 
carbon ; but as these combinations are always gaseous — the direct result of electric 
divellent agencies — we incline to believe that they pass ofi" into the atmosphere 
and then enter (according to the nature and wants of the individual i^lant) the 
stomates of the leaves. 
