The olfactory memory is associative and the sense of smell never sleeps. This is a good thing indeed! This connection is wired in our survivor brain since ancient times. A smell of buring wood will awaken us from the deepest slumber and bring us to the alert in a jiffy.
Saint-Denys preferred techniques were based on conditioning, i.e., he repeatedly paired, during his waking hours, a particular situation with a simple stimulus which he then arranged to have presented to him while he was asleep in order to evoke images from the waking situation in his dream. For example, he took a certain perfume with him on a vacation in the Country and used it constantly. Upon his return, he had someone place a few drops of the scent on his pillow while he was asleep, and thereby succeeded, not just once but in repeated experiments, in stimulating dream images linked with impressions from the vacations. He found that he was able to use up to seven or eight different fragrances as stimuli to evoke associated ideas in his dreams, using this procedure. He even speculated that if one wishes to have pleasant dreams, one should take care to intersperse one’s daily activities with pleasant impressions, which would then naturally occur in dreams due to their associative linkages!
See also: Bibliography, Booze and dreams, Dream cycles, Dream glossary, Dream hacking, Dream recall, Dreams and brain disorders, Dreams as a source of inspiration, Essential oils, Food and dreams, Herbs for dreaming, Hypnagogic state, Lucid dreaming, Neuroprotective agents, Precognitive dreams, Psychic dreams, Recurring dreams, Shamanic dreaming, Sleeping brain, Sleep deprivation, Weed and dreams, WILD, Yoga Nidra