THE AMERICAN BOTANIST. 
73 
^^egetation of past ages, of the sunshine of their time. 
Directly or indirectly, therefore, we always come at last 
to the sun as the impelling vital force, and in connection 
therewith we equally invariabl3' find that this force can 
only find vital expression through the vegetation which 
clothes the world with verdure; naturally, therefore, we 
find a certain synchronism to exist between cause and 
effect; that is, between vital vegetative activit3%and solar 
influence, especially as solar light and solar heat are so 
intimately associated, and the heat is also a factor in leaf 
development. 
The next thing to consider is how the sunshine is 
enabled to do its vital work within the leaves, and 
although it is impossible for us to define the actual '^how" 
we absolutely know that the work is entirely done by the 
green coloring matter itself, the so-called chlorophyll, 
which is really the simple Greek of leaf color. Within the 
partially transparent cells w^hich form the fabric of all 
leaves this coloring matter exists as an infinite number of 
tiny green grains, which, tinder the influence of light are 
enabled not only to multiply, but in some subtle way to 
break up or decompose the carbonic acid gas of the air 
which is absorbed by the leaves through their pores, and 
such salts as may be contributed from the soil through 
the roots; and also to recombine their elements in infinite 
ways to form woody and leafy tissue, and, in short, build 
up the plant on wider and wider lines. 
If we pause a moment to consider the infinite variety 
of flavors, odors, and chemical products which exist in 
the plant world, and remember that all of these, nutriti- 
ous, noxious, or even deadly poisonous, are fashioned by 
these little green grains, and that every leaf in the fair 
prospect we may be enjoying is an actual and busy labo- 
ratory engaged in this varied work, our conception of the 
wonders of Nature, and especially of the wonders of 
chloroph^dl, cannot fail to be immensely widened. There 
is, indeed, absolutely nothing else in creation, nothing so 
pervasive and so essential to life, which can be compared 
