2 BOOK OF THE SCENTED GARDEN 
I have said enough to show that we need not neces- 
sarily go to the flowers or blossoms alone for the sweet 
odours that bring fragrance and health in their train. 
The fragrance of leaves, as of flowers, is mainly due to 
the presence and secretion of essential and often volatile 
oils of various kinds. Such common examples as Rue, 
Rosemary, Lavender, Ladslove, Wormwood, Euca- 
lyptus, Myrtle, Sweet Bay Laurel, Diosma, Scented 
Pelargonium, Allspice, Cinnamon, Patchouli, Orange and 
Lemon leaves, Thyme, Balm, Mint, Sage, and Marjoram, 
are all pretty well known, but in the world’s great wild 
garden the variety is enormous, and the economic im- 
portance of the essential oils secreted by green leaves 
has as yet not been told. Next to the dynamics of plant 
growth, there is no unworked field of original research 
so attractive and that promises to be so productive as 
does this question of odorous leaves. 
Apart from the chemist and the physiologist, even the 
physicist may learn much from the odorous leafage of 
the desert and the prairie. It is not for nothing that 
some leaves are filled with oil cells while others do not 
produce them, for we now know that nothing, however 
seemingly trifling, nothing is useless, nothing is created 
in vain. Even in prosaic practical matters, scents and 
flavours have to be dealt with by the doctor and the 
cook, and our food as well as our medicines would not 
please us so well, were it not for the subtle scents and 
delicate flavours we can impart to them by the aid and 
ministration of ‘“‘ nothing but leaves.” ‘‘ Nothing but 
leaves ” indeed, when without green leaves our life here 
would be impossible. 
The green leaf is the greatest and most perfect of all 
chemists. It can take up or absorb earth-salts in water, 
and carbonic dioxide in air, and form starch or sugar 
interchangeably. Our wisest chemists of to-day can 
form sugar out of starch, but no chemist (except a green 
