UN THE FOOD OF PLANTS. 
309 
cation of the food of plants, and the manner in which the subject has 
been discussed appearing to me to be calculated rather to lead a prac¬ 
tical man astray, than to establish such demonstrative truths as will 
lead to improved methods of cultivating the eaith, 1 take the liberty of 
offering a few axioms for the consideration of your readers. 
1st. Plants require food to sustain them, as much as animals. 
2nd. From the peculiar formation of plants, they cannot take up any 
thing into the system as food, but in a state of solution in water. 
3rd. The quantity and quality of the food supplied to plants, deter¬ 
mine their growth and produce. 
As to the first, we need not attempt to offer proofs that plants cannot 
grow without water. And as to the second, although many of the 
most ingenious experiments have been made, it never has been proved 
that plants imbibe or take up any substance, except in a state of 
solution. And as to the third, the two first being admitted, that must 
follow as a matter of course. Although it is proved that plants may be 
sustained alive, and will acquire some extension of bulk when supplied 
with no other matter than what is contained in pure water; yet it is 
proved, that in water alone, plants will never attain any thing like the 
size and proportions as when supplied with carbonaceous matter, nor 
will they ever fructify when grown in water alone. And if it be 
proved that plants will grow to their utmost extent, and fructify in 
perfection, when duly supplied with carbonaceous matter, it must be 
just to infer, that such carbonaceous matter as is necessary to sustain 
plants, is absorbed by them from the soil or substance in which they 
grow, and, consequently, that in course of time, plants, by growing in a 
soil must exhaust its carbonaceous matter, and that by such abstraction 
the soil must become more or less sterile. To suppose, then, that 
simple earth and water can, by being simply stirred and exposed to the 
atmosphere, be rendered capable, and kept in a state of capability, to 
sustain vegetables in their production of fruit and seeds, must be con¬ 
trary to common sense as well as to experience. But although the 
professed advocates of Jethro Tull seem to indulge in visionary conclu¬ 
sions, I do not mean to assert that he himself was a mere visionary ^ 
nor that his estimations of the effect of horse-hoeing were groundless: 
the following facts will show how such operations may be profitably 
productive. If a quantity of the leaves of trees be collected, and 
immersed in a cistern or pool of stagnant water, and permitted to remain 
undisturbed for three years, they will be decomposed, and in appear¬ 
ance will be in that state which, placed on the surface of the earth, 
should form a fertilising substance; yet it will be found so sterile that 
no plant will grow in it. But, if the same quantity and kind of leaves 
