I love a good mystery story, especially one that reveals real-life secrets of the natural world. One of my favorite examples is a story I first encountered almost a decade ago. Driving home through Sullivan County one afternoon, I tuned the radio to WJFF midway through an episode of Ira Flatow’s great NPR program “Science Friday.” The guests were Neil Theise, a professor of pathology at New York University School of Medicine, and Rebecca Wells, a professor of medicine and bioengineering at the University of Pennsylvania in Philadelphia. They were describing their revelatory research about interstitial tissue, which is found throughout the human body. Perhaps because I only knew the word interstitial in the context of buildings as a term for the volume of space between walls and above ceilings—the space where insulation, plumbing and electrical stuff live—my ears pricked up.

Anatomists have known about interstitial tissue for more than 150 years, and accepted wisdom described the interstitium as a flat, dense wall of tissue that wraps and cushions the organs because that’s what it looks like in processed samples removed from the body.  Using state-of-the-art optical imaging tools and techniques, Theise and Wells and their interdisciplinary team were able to observe the living tissue in place.  They saw the true nature and function of this tissue: not flat at all, but a continuous three-dimensional, honeycomb-like circulatory system filled with fluid in which “bundles” of collagen float. This system plays a role in numerous functions of tissues and organs, and helps explain a number of mysterious phenomena such as signal cells, edema, autoimmune disease, how scar tissue forms, how immune cells are circulated through the body, and how cancer cells metastasize. It may also help explain the efficacy of acupuncture and osteopathic medicine. 

For weeks I bored my friends and co-workers with my awestruck but distinctly non-medical understanding of this important story. Even now it fills me with delight to know that scientists who dare to ask “what if” can upend centuries-old assumptions. I also take pleasure from the juxtaposition of another figurative use of the term “interstitial” to describe a transitional space outside formal confines—the hallways, lobbies and breakrooms where informal conversations can lead to new connections and discoveries.    

Another such story came my way this past summer, through a thought-provoking piece by science writer Rivka Galchen in the New Yorker.  What if there are colors on the spectrum that we can’t see or imagine? In April 2025, researchers at the University of California, Berkeley published a paper describing their experiments with color perception beyond the range of normal human vision. The researchers—Ren Ng, a professor of computer science, and Austin Roorda, a professor of vision science and optometry—created a device that delivers tiny doses of laser light to individually control up to 1,000 photoreceptors in the eye. Those photoreceptors include the cone cells that enable us to perceive color. Short-wave (S) cone cells perceive the blue wavelength, medium-wave (M) cone cells perceive green, and long-wave (L) cone cells perceive red; the mix of these three colors in normal vision creates our everyday visual perception of the world. 

In the laboratory, Ng and Roorda’s device was able to tune laser light to stimulate M cones only, something that never happens in natural vision where the action of S, M and L cone cells overlap. Test subjects reported seeing an intense green color beyond anything they had ever experienced, which the researchers named “olo,” a color they proclaimed to be completely new and impossible to replicate, existing only through the action of their device. It was interesting to note that each of the seven test subjects who had seen olo described it differently, from “the greenest green” to “iridescent peacock” to “teal,” reflecting the very personal and subjective nature of color perception. One commented that, since the experience could not be repeated and the memory of it was ephemeral, she was no longer sure what she had seen.

The Berkeley experiments highlight the elusive nature of vision itself. In her article, Rivka Galchen also cited the work of Dr. Gabriele Jordan of Newcastle University in England, who studies women born with a fourth retinal cone cell, a phenomenon that also occurs in certain species of birds, amphibians, fish, reptiles, as well as mammals like reindeer. The human genetic variation occurs on the X chromosome, and scientists estimate that about 12 percent of women have fourth cone cells that are more sensitive to the yellow-green range of the color spectrum. Only a much smaller subset of these women are able to process the information to perceive colors outside the range most of us experience. Most are unaware that they possess a color perception variation, since none of us has an objective means of comparing how we see things to how another individual does. Coincidentally, Dr. Jordan has also discovered that many individuals with so-called “color deficiencies” can perceive hues that are not visible to “color-normal” study participants.  

Nature’s benevolent compensation?  Other mysteries await.