2(58 ON THE DEVELOPMENT OF VEGETABLE ORGANISATION. 
granules of the Lepraria viridis, that green powdery incrustation which 
is found in such abundance on trees, old posts or rails, walls, &c., in 
damp shady situations. This green crust is in fact one of the most 
simple forms of vegetable being with which we are acquainted, and 
when examined with the aid of a powerful microscope, will be found 
to consist of innumerable small granules of a spherical shape, very 
loosely connected together in fours. That these granules are vesicular 
is evident, for by touching them with the point of a small needle, when 
viewed in water under the microscope, their filmy coats will be rup¬ 
tured, and will be observed to present irregular torn edges. 
It is not meant to be asserted that these granules, cells, or vesicles are 
perfectly simple — that they are the ultimate organic elements of 
the plant; for it is not at all probable that we should here have 
arrived at the real elementary composition. On the contrary, there is 
much reason to believe that the external filmy coating of these filmy 
vesicles, though of such extreme tenuity, is itself compounded of nume¬ 
rous other cells,—that it, in fact, consists of a congeries of vesicles 
of inconceivable minuteness so united together as to form a continuous 
surface ; each of which secondary vesicles, as they may be termed, may 
possibly also be compounded in like manner, and so on to an extent 
which it is utterly beyond our powers to comprehend. To the limits of 
minute division in the works of the Great Creator, there appears 
no bound. Were it not that all the parts of His creation clearly prove 
that magnitude and number present no restraint to his operations— 
that the vast and the minute are equally the object of his attention— 
w T e should often be tempted to throw aside many of the sublime truths 
of natural science as the wild reveries of a heated imagination. But 
every department of scientific research leads to the same conclusions, 
overwhelming as they are to the pow r ers of the human intellect, and 
every mode of investigation teaches the same results; and while 
we make the vain attempt to conceive the wonders of creation, we can 
only pause and admire when the faint glimmering perception, which 
alone we are able to obtain, arises in our minds. 
But to proceed, without entering further into a question which 
is quite beyond our powers, this green powdery crust in its elementary 
composition—elementary, as it appears to our eyes, may represent what 
is to us the ultimate forms of vegetable organisation. A simple vesicle 
connected in this instance with similar vesicles by quaternary arrange¬ 
ment; in others, as in some of the Conferva and various plants of the 
Alga tribes, by a binary, ternary, or linear mode of arrangement. 
If a number of these elementary vesicles be so arranged in simple 
contact as to take up the smallest possible space, a section of them will 
