The Science of Smell
The human sense of smell is 10,000 times more sensitive than the sense of taste.
It is possible to detect thousands of different smells.
A few fragrance molecules are enough to activate the extremely sensitive olfactory receptors within the nasal cavity.
Of the 5 human senses smell is ranked as the middle one and of more significance than taste and touch.

Linked to Memories
When fragrance molecules stimulate the olfactory receptors, they transmit impulses to the brain. This pathway is directly connected to the limbic system, the part of the brain that deals with emotions.
That is why reactions to smell are rarely neutral.
Smells also leave long-lasting impressions and are strongly linked to memories.
The sense of smell can create immediate and total recall of long forgotten memories.