the
same substance is smelled outside the mouth, we could not fail to
notice that the "tastes" were largely composed of odor. The obtrusive
thing about a blend is the total effect, not the elementary sensations
that are blended.

The Sense of Smell

The great variety of odors long resisted every attempt at
psychological analysis, largely because the olfactory end-organ is so
secluded in position. You cannot apply stimuli to separate parts of
it, as you can to the skin or tongue. But, recently, good progress has
been made, [Footnote: By Henning.] by assembling almost all possible
odors, and becoming thoroughly acquainted with them, not as
substances, but simply as odors, and noting their likenesses and
differences. It seems possible now to state that there are _six
elementary odors_, as follows:

1. Spicy, found in pepper, cloves, nutmeg, etc.

2. Flowery, found in heliotrope, etc.

3. Fruity, found in apple, orange oil, vinegar, etc.

4. Resinous, found in turpentine, pine needles, etc.

5. Foul, found in hydrogen sulphide, etc.

6. Scorched, found in tarry substances.

These being the elements, there are many compound odors. The odor of
roasted coffee is a compound of resinous and scorched, peppermint a
compound of fruity and spicy.

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Each elementary odor corresponds to a certain characteristic in the
chemical constitution of the stimulus.

The sense of smell is extremely delicate, responding to very minute
quantities of certain substances diffused in the air. It is extremely
useful in warning us against bad air and bad food. It has also
considerable esthetic value.

Organic Sensation

The term "organic sensation" is used to cover a variety of sensations
from the internal organs, such as hunger, thirst, nausea, suffocation
and less definite bodily sensations that color the emotional tone of
any moment, contributing to "euphoria" and also to disagreeable states
of mind. Hunger is a sensation aroused by the rubbing together of the
stomach walls when the stomach, being ready for food, begins its
churning movements. Careful studies of sensations from the internal
organs reveal astonishingly little of sensation arising there, but
there can be little doubt that the sensations just listed really arise
where they seem to arise, in the interior of the trunk.

Little has been done to determine the elementary sensations in this
field; probably the organic sensations that every one is familiar with