The mamaillian olfactory system is the least well understood of the senses. A particular
difficulty is that smells are subjective and difficult to define compaired with, say, a
colour. The physical components of the system are known but the exact mode of operation of
the 'sensors' is still subject to debate.
The Olfactory System
It is known that the region of the brain responsible for the sense of smell is also
responsible for emotions and quite distinct from the other senses.