58 
THE FOLIAGE— AND ITS FUNCTIONS. 
condensed water, the dry plant will continue to flag, till its soil receive and imbibe 
to its centre that quantity of water which its specific temperament requires. 
Herein also, the real skill and discrimination of the gardener are brought to the 
test ; for, as plants differ much in their requirings, a great degree of knowledge and 
judgment are called for, otherwise, one subject may be swamped, while another is 
scarcely kept alive. 
One more quotation, and then, having adduced evidences of the possible fallacy 
of modern theorists, we will, in fairness, give them every advantage which our own 
observation enables us to bring forward. 
In proof, as it is supposed, that carbon is derived from the atmosphere, we read, 
that, " It is now pretty certain that plants generally derive their carbon from the 
air. A forest in Scotland, which was planted fifty years since, now contains more 
charcoal than it did at the commencement of the period." — (Have not all the leaves 
fallen yearly, and by decay produced a blackened earth?) — " Nitrogen, in the form 
of ammonia, is also derived from the air to a great extent, being brought down by 
means of rain. It (ammonia) has been detected in rain-water, when sought for, and 
likewise in snow, and is thus known to exist in the air. Whether all plants derive 
all the nitrogen they want from the ammonia of the air, is another question ; it is 
not a well settled point, and we want agricultural experiments to decide it." 
This closing and modest addition, is conclusive : — an hypothesis exists — it is of 
recent date — proofs are wanting ; therefore the whole rests upon a conjectural basis. 
The lecturer, as we have seen, asserts that ammonia exists in the air ; and that rain 
and snow conduct it to the earth. Direct experiment has, really, proved this fact ; 
but, what then ? Admit that every shower shall so convey a portion of that ammonia, 
which had been received into the atmospheric volume, during the decomposition of 
animal matter, and the exhalation of ammoniacal gas from heaps of manure, and the 
like fermenting substances ; yet, if it fall to the ground, and soak into the soil with 
the rain or snow, which had been its solvents, does the theory of absorption by the 
leaves receive any support from the admission? On the contrary, the ground 
becoming the recipient, we should rather be inclined to think that the fluid ammonia, 
so situated, must enter the organism through the channels of the roots. 
Thus far, doubt has been maintained, on the ground of what appears to be 
fallacious experiments, conducted upon artificial principles. But, if we recur to pure 
nature, free from the experimentum crusis of the laboratory, and its death-dealing 
gases, facts may be appealed to, that, to say the least of them, will confer probability 
upon the modern theory. First, then, there are numbers of plants, wild weeds of 
the field, uninterfered with by man ; and others, cultivated as food or fruit, which 
produce a system of foliage, so vast, so infinitely extended, when compared with the 
stems, that it is scarcely possible to refer to any other channels of nutriment than 
those of the leaf-pores or stomates. Take, as one example, the common Chickweed, 
and compare its hair-like, slender stem with the numerous thicker branch-stalks 
and their thousands of appendant leaves. As another example, look at the Cucumber, 
