32 
that the characteristic marks of plants are to be found. 
The veins of leaves are to them what the muscles 
and veins are to the animal structure. In both cases 
they are hidden below the surface. We do not actu¬ 
ally see them, but we perceive the result of their 
presence in the elevations, depressions, and undula¬ 
tions of the structure to which they belong. And as 
we know that in the human figure it is of the first 
importance to attend to these circumstances, so is it 
equally necessary in representing plants; for the veins 
hidden below the leaves have a different management 
in different species, and that arrangement mainly deter¬ 
mines the appearance presented by the leaves to the eye. 
72. Generally, the veins are arranged with exact 
symmetry ; they regularly divide into arms, which sub¬ 
divide into other arms, and eventually lose themselves 
in minute capillaries, which last produce no particular 
effect upon the surface. The way in which the veins 
are arranged is different in different plants, however 
much they may look like each other, and any substi¬ 
tution of one kind of arrangement for another is fatal 
to resemblance. 
73. For example, take the leaves of the Vine and 
the Plane tree, in which there 
is the same general form, so that 
one might be almost mistaken 
for the other. The veins of 
both proceed from the base to 
the points of the divisions of 
the leaf. Each division is stiff¬ 
ened by a rib passing from the 
insertion of the stalk to its 
point. But some difference in 
their appearance catches the 
VINE LEAF. 
eye, and gives each a peculiar character, which ren- 
