Of all the conventional five senses (as distinguished from the less-considered senses like orientation in space or internal distention, or non-ocular light sensitivity) smell is the most primal, since it is the earliest sense, present even in a one-celled animal, for it is the detection of molecules in dispersal, either in fluid or gas. Those without this perception cannot find substances nor avoid substances, nor distinguish whether they are good or bad.
In mammals the sense of smell is directly connected to the brain, even more so than the eyes, and linked neurally directly to the hippocampus which is the locus of memory sorting for preservation. Smells and information or incidents linked with smells are more memorable -- remembered longer and more vividly. Memories connected to “unpleasant” odors (subjective as that may be) are remembered better than those associated with “pleasant” odors. This makes sense in two ways: toxins and rot should be remembered so as to avoid them, and the funky smells of intimate bodies associated with intense stimulation (not just pheromones) should not be forgotten for positive reasons. But unless you’re a bee, the smells of flowers don’t matter that much -- they are decorations.
Octavian Coifan, on his blog called 1000fragrances.blogspot.com, is often eloquent about the primal connection between perfumes and religion. Consider this review of Aesop Mystra, which comes in a small brown bottle as though it were medicine.
“. . . Taking inspiration from religion or past is a hard work but Aesop succeeds at it in all ways. It's not the opulent sexy Byzantine perfume that would make you feel attractive .... but a mysterious mixture like a formula from the past that would transport you in other world. The main ingredients are incense, labdanum and mastic, and a lot of other naturals that would make it dark and uneasy to explore. There is an unusual quality I found inside - it’s profoundly animalic and dirty like a sinful woman. It has the combination of jasmin-amber-musk of the old world. . . a whisper of death in a decadent universe. “
Unafraid of being offensive because he’s in pursuit of deep truths, he traces the associations of perfume to the preservation of the dead, the attempt to prevent corruption, the need to disinfect, and the original substances used by the Egyptians for mummification. “Natron” (which is merely sodium bicarbonate to dry the tissues), minerals, bark derivatives, alcohol, acids, salts, resins, oils were all used and became associated with the hope for an afterlife. Frankincense and myrrh. All aromatics.
Another source of memorable smells is fire and burning. Smudges. Incense. For those people who maintained household fires, the collection and uses of different kinds of wood became a vocabulary in themselves: what burns hot, what makes smoke, what holds embers -- each with a distinctive smell. Through the long period when religious offerings were creatures, burnt flesh in the temple sent messages to Heaven. Add burnt feathers, bone and hair. Ritual cremations of humans at death. As soon as people understood how to make a fire hot enough to smelt metal, those pungent smells also became associated with acts so powerful and mysterious as to amount to magic.
Tanning is a messy process, fairly odorous. First, some means of removing the water in the new skin with salt or other dessicant is necessary; then working out the sub-cutaneous fat, perhaps by diluting it with the fat of brains, well rubbed in; and then removing the glue with a mild acid, maybe vinegar or urine. Native Americans used smoke to preserve. In Europe elegant leather gloves, still retaining a whiff of tanning methods, were all the rage in some historical periods, and traditionally scented by keeping them in a sandalwood box. Shawls being shipped from India were packed with patchouli, an aromatic plant that repels insects. Tobacco and sweetgrass did that, too. Maybe camphor or menthol. Where there is wealth, there are preservatives.
The smells of the pest house and various corruptions were fought with vapors of sulphur and solutions of iodine, all the disinfectants like ammonia or pine-sol and lye. Garlic and mustard were used as poultices. Even so came creeping the reeks of excrement, vomit and rot. Skilled doctors used their noses as much as their eyes to understand what was happening. Not many of us know the smell of blood as well as they did. (I’ve never understood why it smells coppery when it is in fact mostly iron.)
Then the smells of food preservation: pepper, chili, vinegar, char, cinnamon, dill, various dried substances both animal and vegetable, sometimes mineral. The smells of distillation and fermentation, baking and roasting, fresh torn greens and newly shucked peas or corn. These are life-sustaining odors, associated with contentment and energy. The Christian tradition has chosen bread and wine to celebrate, when they could have chosen dried fish or even burnt flesh, but those were about earlier times before households had the time and stability to grind flour or ferment grapes.
The smells of the city and of the industrial age are with us now, but not so associated with religion though they certainly saturate our understanding of reality. Hot asphalt, new tires, WD40, gasoline fumes, hot metal, a passing cigar smoked in the rain on a cold day. Perhaps churches have smells of their own: lemon oil rubbed into the pews, beeswax candles.
Years ago when I was in the ministry I attended the UUA General Assembly back east. It was pretty miserable, too hot and humid. When I got back, I stepped into the dry wind of the little Helena airport and found that all the sweet clover had just bloomed, billowing in a yellow cloud everywhere. When the burnt jet fuel blew off, which didn’t take long in a stiff Montana breeze, I was saturated by the honeyed smell of those weeds. It was so healing that I sat down on the curb instead of going to my pickup and on home. I sat there a long time. Sure, I know that the “sweet” smell of sweetgrass and sweetclover and even sweetpine (balsam fir) is coumadin, which is the blood thinner many people take as medicine. It’s the effective ingredient in rat poison (renamed Warfarin). But my blood needed thinning.
Something similar happened again on another occasion except that I was flying in and out of Portland and got back on a warm spring evening when the frogs had just burst into song in the slough next to the airport parking lot. I stayed there a while, too, watching the full moon rise over the Columbia River. These two threshold experiences are so deeply embedded in my sense memory bank that when I grow very old and can’t smell anymore, I’ll still be able to summon at least one Holy smell and one Sacred sound.