THE ROOT. . 9 
is not difficult to understand. In the bosom of the earth they 
meet with obstacles which leaves and branches never meet with in 
the air. The latter consequently spread freely in every direction, 
whilst roots are incessantly stopped by all sorts of obstacles. 
They are constantly cramped in their lengthening or thickening, 
and are forced to turn aside from the course which they ought 
naturally to follow, and obliged to twist round to surmount the 
impediments opposed to them by the unequal hardness of the soil, 
the presence of walls, rocks, or of other roots. From these causes 
arise the deformities which we notice in their outward structure, 
and the numerous windings observable in their branches. 
The manner in which roots succeed in overcoming obstacles has 
always been a subject of surprise to the observer. The roots of 
trees and shrubs, when cramped or hindered in their progress, 
have been observed to exhibit considerable mechanical force, 
throwing down walls or splitting rocks; and in other cases 
clinging together in bunches, or spreading out their fibres over 
a prodigious space, in order to follow the course of a rivulet with 
its friendly moisture. Who has not seen with admiration how 
roots will adapt themselves to the special circumstances of the soil, 
dividing their filaments in a soil fit for them almost to infinity, 
- elsewhere abandoning a sterile soil to seek one farther off, which 
is favourable to them; and as the ground was more or less hard, 
wet or dry, heavy or light, sandy or stony, varying their shapes 
accordingly ? We are compelled to acknowledge that there is in 
these selections made by roots a true manifestation of vital 
instinct. 
Duhamel, a botanist of the last century, relates, that, wishing 
to preserve a field of rich soil from the roots of a row of elms 
which would soon have exhausted it, he had a ditch dug between 
the field and the trees, in order to cut the roots off from it. But 
he saw, with surprise, that those roots which had not been severed 
in the operation had made their way down the slope so as to avoid 
meeting the light, had passed under the ditch, and were again 
spreading themselves over the field. It was in reference to an 
occurrence of this kind that Bonnet, the Swiss naturalist, said 
that it was sometimes difficult to distinguish “a cat from a rose 
tree ;” a quaint, if not a witty remark. 
