Synesthesia is the fascinating neurological phenomenon whereby stimulation of one sense involuntarily triggers another sensory pathway. A synesthete might taste sounds or hear colors. Now, computer scientist Jas Brooks and colleagues from the University of Chicago are creating a kind of digital synesthesia by using odors to trick your brain into experiencing different temperatures in virtual reality. For example, capsaicin, the chemical in hot peppers, triggers a warm feeling while eucalyptol elicits a cool sensation. Evan Ackerman explains in IEEE Spectrum:

The trigeminal nerve [in your nose] connects your brain to most of your face, and it carries a bunch of sensory information, including both smell and temperature. The actual temperature-sensing mechanism comes from transient receptor potential (TRP) ion channels, and while we can skip over exactly how these work, the important thing to understand is that some of these TRP channels can get triggered by either skin temperature or certain kinds of aerosolized chemicals. You’ve almost certainly experienced this for yourself: When you smell peppermint, it feels cold, because the menthol in the peppermint is triggering a receptor in your trigeminal nerve called TRPM8 that responds to both the menthol and temperatures under 25 °C. On the other end of things, capsaicin (which you can find in hot peppers) triggers the TRPV1 receptor, which also responds to temperatures above 42 °C. That’s the key: One receptor that can be triggered by temperature or a chemical, but sends the same temperature sensory message to your brain. The researchers describe this as “a perceptual duality,” and if you aerosolize one of these chemicals and puff it up your nose, you’ll feel a temperature change.[...]

Smell is perhaps more closely intertwined with memory than sight, sound, or any other of our senses. Indeed, scents are an incredibly important part of history and culture. That's why Cecilia Bembibre and her colleagues at the UCL Institute for Sustainable Heritage are working to preserve certain smells for the ages. After all, smells are "the olfactory heritage of humanity," she says. ”From the BBC:

But how do you capture something as intangible as a historical scent? One method involves exposing a polymer fibre to the odour, so that the smell-causing chemical compounds in the air can stick to it. Then Bembibre analyses the sample in the laboratory, dissolving the compounds stuck to the fibre, separating them and identifying them. The resulting list of chemicals is effectively a recipe for the scent.

Another method separates and identifies the compounds directly from the gas sample – an approach commonly used in the perfume, food and beverages industry, as it allows volatile odour-active compounds to be identified. A third way is to use the nose itself, either by asking panels of people to describe certain smells, or by asking expert “noses”, who may be perfumers or scent designers.

“We characterise the smell from the human point of view,” adds Bembibre. “This is important because if we want to preserve it for the future, it depends on many factors. Not only the chemical composition but also our experience.”

Bembibre has chemically extracted the smells of old leather gloves, ancient books and mould Bembibre has chemically extracted the smells of old leather gloves, ancient books and mould, among other things.

Physicians removed a balloon packed with marijuana from a fellow's nasal cavity 18 years after he smuggled it into prison. The 48-year-old man is now just fine. Physicians from Westmead Hospital in New South Wales, Australia, reported on the unusual case in the British Medical Journal. Apparently the man's girlfriend handed him the package that he shoved up his nose for safekeeping. The package made its way into his nasal cavity where he lost track of it. From CNN:

"A 48-year-old man was referred to the Westmead ENT Department after a CT of the brain, originally performed for headaches, demonstrated an incidental 19x11mm calcified lesion in the right nasal cavity," the report states.

"On questioning, the patient confirmed a long history of unilateral right nasal obstruction and recurrent sinonasal infections."

The rhinolith was removed from the man's nose under general anesthetic, and a subsequent study revealed that it contained a "rubber capsule containing degenerate vegetable/plant matter."

"On follow-up and specific questioning, the patient was able to recall an incident that occurred 18 years prior, while he was incarcerated," the report states. "He remained unaware of the package's presence until presented with the unusual histopathology report."

image: Patrick J. Lynch, medical illustrator (CC BY 2.5) Read the rest

In the early 20th century, James "Smelly" Kelly used his legendary sense of smell and DIY inventions to find hazards, leaks, elephant poop, and eels that were causing problems in the New York City subway system. Atlas Obscura's Eric Grundhauser profiles the the man known as The Sniffer:

In addition to finding water leaks and plumbing issues, Kelly was also responsible for detecting dangerous gas and chemical leaks. From invisible gas fumes that could be ignited by a random spark, to gasoline draining into the system from above-ground garages, Kelly was there to find them out using his allegedly hypersensitive nose.

The most sensational tale of Kelly’s sense of smell was the time he was called to a 42nd Street station to suss out a stench that had overtaken the platforms. According to Kelly’s own account, the smell was so bad it almost bowled him over, but as he got his head back in the game, he pinpointed the source of the reek as… elephants. Amazingly, he was correct. The station in question had been built beneath the location of the old New York Hippodrome, which had been torn down in 1939. The Hippodrome had often featured a circus, and layers of elephant dung had ended up buried at the site. A broken water main had rehydrated the fossilized dung and subsequently leaked into the subway. Until, that is, Smelly Kelly was able to identify it.

"The Man Who Used His Nose to Keep New York’s Subways Safe" (Atlas Obscura) Read the rest