CHAP. I. 
CELLULAR TISSUE. 
11 
been described ; for in that case colours would necessarily 
run together. 
Cellular tissue is generally transparent and colourless, or at 
most only slightly tinged with green. The brilliant colours 
of vegetable matter, the white, blue, yellow, scarlet, and other 
hues of the corolla, and the green of the bark and leaves, is 
not owing to any difference in the colour of the cells, but 
to colouring matter of different kinds which they contain. 
In the stem of the Garden Balsam (Impatiens Balsamina), a 
single cell is frequently red in the midst of others that are 
colourless. Examine the red bladder, and you will find it 
filled with a colouring matter of which the rest are destitute. 
The bright satiny appearance of many richly coloured flowers 
depends upon the colourless quality of the tissue. Thus, in 
Thysanotus fascicularis, the flowers of which are of a deep 
brilliant violet, with a remarkable satiny lustre, that appear- 
ance will be found to arise from each particular cell contain- 
ing a single drop of coloured fluid, which gleams through the 
white shining membrane of the tissue, and produces the 
flickering lustre that is perceived. The cause of colour in 
plants will be spoken of hereafter in the second book. 
The manner in which cellular tissue is generated and grows, 
would appear to differ in different' plants. Amici says that 
the new tubes of Chara appear like young buds, from the 
points or axils of pre-existing tubes, an observation which has 
been confirmed by Slack. It has been stated by Mirbel that 
the same thing occurs in the case of Marchantia polymorpha. 
That learned botanist, in the course of his inquiries into the 
structure of this plant, found that in all cases one tube or 
utricle generated another externally, so that sometimes the 
membranes of newly-formed tissue had the appearance of 
knotted or branched cords. He satisfied himself that new 
parts are formed by the generative power of the first utricle, 
which spontaneously engenders on its surface others endowed 
with the same property. The amylaceous vesicles of malt in 
a state of fermentation manifestly produce new vesicles from 
their sides externally ; and Turpin asserts that they also con- 
tain molecules, which are the rudiments of other cells. 
This subject has lately engaged the attention of Professor 
