53 
LECTURE III. 
ON THE ORGANIZATION OF PLANTS. OF THE ROOTS, 
TRUNK, AND BRANCHES. OF THEIR STRUCTURE. OF 
THE EPIDERMIS. OF THE CORTICAL AND ALBURNOUS 
PARTS OF LEAVES, FLOWERS, AND SEEDS. OF THE 
CHEMICAL CONSTITUTION OF THE ORGANS OF PLANTS, 
AND THE SUBSTANCES FOUND IN THEM. OF MUCIL- 
AGINOUS, SACCHARINE, EXTRACTIVE, RESINOUS, AND 
OILY SUBSTANCES, AND OTHER VEGETABLE COMPOUNDS, 
THEIR ARRANGEMENTS IN THE ORGANS OF PLANTS, 
THEIR COMPOSITION, CHANGES, AND USES. 
V ariety characterises the vegetable kingdom, yet 
there is an analogy between the forms and the 
functions of all the different classes of plants, and 
on this analogy the scientific principles relating to 
their organization depend. 
Vegetables are living structures distinguished 
from animals by exhibiting no signs of perception, 
or of voluntary motion ; and their organs are either 
organs of nourishment or of reproduction ; organs 
for the preservation and increase of the individual, 
or for the multiplication of the species. 
In the living vegetable system there are to be 
considered, the exterior form, and the interior 
constitution. 
Every plant examined as to external structure, 
displays at least four systems of organs — or some 
analogous parts. First, the Root . Secondly, the 
e 3 
