Page 20 - The Miracles of Smell and Taste

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ing smell. For instance, water molecules that vaporize after a downpour
of rain raise scent particles up into the air and assist in spreading the scent
of flowers all around.

No one knows how many varieties of odors there are in nature.
Bearing in mind the existence of millions of molecules, we may safely say
that the variety of scents is enormous. Studies have been carried out to
place these aromas into various categories. But due to the extraordinary
variety of smells, no satisfactory classification has ever been achieved. 1
The microscopic variation between molecules gives any one smell its
particular characteristics. (Figure 1) For example, the feature that differ-
entiates a cooked, fresh egg from a rotten one lies in the structures of the
particles the two eggs give off. Differences in the chemical structures be-
tween various molecules are based, in turn, on very delicate variations. 2

Indeed, the addition or subtraction of a single carbon atom can turn an at-
tractive smell into a repellent one!
(Figure 1)
The three deriva-
tive scents of the
chemical sub-
stance whose
structure is shown
in (91) resemble
that of the rose.
Yet each is distin-
guished from the
other two by a dif-
ferent smell. The
scents of lilac and
spices (92), ozone
and fruit (93) and
cinnamon, carna-
tion, spices and li-
lac all smell like
the rose mixed
with these scents.
The Miracles of Smell and
Taste