f each, and arrive at the lowest forms of animals and
plants, we there meet with bodies of the simplest structure, sometimes a
mere cell, whose organization, modes of development and reproduction,
are so anomalous, and partake so much of the character of both, that we
cannot distinguish whether they are plants or whether they are animals."

1070. WHILST IT IS DIFFICULT TO DETERMINE where the animal begins and
the vegetable ends, it is as difficult to account for many of the
singularities by which numbers of plants are characterized. This,
however, can hardly be regarded as a matter of surprise, when we
recollect that, so far as it is at present known, the vegetable kingdom
is composed of upwards of 92,000 species of plants. Of this amazing
number the lichens and the mosses are of the simplest and hardiest
kinds. These, indeed, may be considered as the very creators of the
soil: they thrive in the coldest and most sterile regions, many of them
commencing the operations of nature in the growth of vegetables on the
barest rocks, and receiving no other nourishment than such as may be
supplied to them by the simple elements of air and rain. When they have
exhausted their period in such situations as have been assigned them,
they pass into a state of decay, and become changed into a very fine
mould, which, in the active spontaneity of nature, immediately begins to
produce other species, which in their turn become food for various
mosses, and also rot. This process of growth and decay, being, from time
to time, continued, by-and-by forms a soil sufficient for the
maintenance of larger plants, which also die and decay, and so increase
the soil, until it becomes deep enough to sustain an oak, or even the
weight of a tropical forest. To create soil amongst rocks, however, must
not be considered as the only end of the lichen; different kinds of it
minister to the elegant arts, in the form of beautiful dyes; thus the
_lichen rocella_ is used to communicate to silk and wool, various shades
of purple and crimson, which greatly enhance the value of these
materials. This species is chiefly imported from the Canary Islands,
and, when scarce, as an article of commerce has brought as much as L1000
per ton.

1071. IN THE VICINITY OF LICHENS, THE MUSCI, OR MOSSES, are generally to
be found. Indeed, wherever vegetation can be sustained, there they are,
affording protection to the roots and seeds of more delicate vegetables,
and, by their sp