The Past Doesn't Smell Like It Used To

Scientists find ways to study and reconstruct past scents

Apr 2022, phys.org

https://phys.org/news/2022-03-scientists-ways-reconstruct-scents.html

They're trying to develop "an archaeology of scent," which is hard because smells are ephemeral, and last only as long as their source. But because of advances in chromatography, mass spectrometry, sequencing technologies and modern bioinformatics, which include metabolomics, proteomics and genomics; they can identify the organic remains preserved on surfaces like walls, ceramic vessels, incense burners, perfume flasks, cooking pots, dental calculus, mummies, and entire streets:

Advanced biomolecular and ‘omics’ sciences enable more direct insights into past scents, offering new options to explore critical aspects of ancient society and lifeways as well as the historical meanings of smell.

The whole paper is very interesting, and although I encourage anyone interested in ancient history to read it, for those who don't, I bring back only this -- palaeofaeces -- it's a thing in archaeology, and now in olfactory archaeology too: "in an Iron Age roundhouse in Scotland, chemical characterization of floor sediments provided insight into living conditions, hygiene practices and the temporary sheltering of animals in human living areas during this period."

-Mackay, H. et al. J. Archaeol. Sci. 121, 105202 (2020). [pdf]

via the Department of Archaeology at the Max Planck Institute for the Science of Human History in Jena, Germany: Huber, B., Larsen, T., Spengler, R.N. et al. How to use modern science to reconstruct ancient scents. Nat Hum Behav 6, 611–614 (2022). https://doi.org/10.1038/s41562-022-01325-7

https://doi.org/10.1038/s41562-022-01325-7

Image credit: AI Art - Animals in Jars - 2022

via James Gilleard and Justin Gerard

Post Script:

Speaking of human history, the Odeuropa project is taking a completely different angle -- they use computer science to identify, scrape, and coordinate pictures that contain smells in them, either by visually recognizing objects tagged as related to smells, or by reading the text captioned with the image. Sensory mining they call it:

Odeuropa is a European research project which bundles expertise in sensory mining and olfactory heritage. We develop novel methods to collect information about smell from (digital) text and image collections.

https://odeuropa.eu/

Olfactory Clues To Disease Discovery

Smells can be a great sign of danger, even when it comes from our own bodies. We've got here a story about a woman who smelled Parkinson's on her husband a good ten years before he was diagnosed. This spurred research into the subject, and we now have an idea of what the smell is and how it fits into the effects of the disease.

Tldr, it comes from the production of excess sebum, which contains chemicals known to be related to altered neurobiology associated with Parkinson's. The scent-sensitive woman who noticed it on her husband described it as earthy and musky.

Then there's the nick-of-time test for Maple Syrup Urine Disease. Although the disease can be verified with a blood test, symptoms could get so bad so fast that the time required for this testing becomes prohibitive. Luckily, it can also be identified by sweet-smelling urine, sweat and earwax.

Maple Syrup Urine Disease is a condition where the body can't break things down properly. If our body's natural defense system is inhibited so much that it can't break down the maple-syrup-molecule, for example, then we've got serious problems.

I am not a doctor so I don't know if this is the same smell/molecule, but Sotolon is the "maple syrup molecule." Other things could be exuding from the body, but this is a potent aroma compound, so it's easy to detect.

As a general rule, if you notice that you smell funny, it's something that should be checked out immediately. For example, fishy odor in the urine could be a sign of a urinary tract infection, and the smell comes from the bacteria living there (as opposed to the improper biotransformation of ingested molecules).

Image source

Post Script:

Then there's the cancer-smelling dogs, surely we've all heard of that. And for the record, if we interfaced with the world the way dogs do, with smell being way more important, and if we spent lots of time smelling all the things around us, including our own bodies, or those of our loved ones, we might notice these things too. But dogs get the credit, because honestly when was the last time you gave your partner a full body sniff-check?

Notes:

A 'Super Smeller' Sniffed Parkinson's Disease Before Symptoms Even Appeared

Mar 2019, Inverse

Doctor saved baby's life by sniffing her earwax to diagnose potentially fatal illness

Mar 2019, The Sun

Study about the smell of Parkinson's:

https://pubs.acs.org/doi/10.1021/acscentsci.8b00879