Imagine peering into the past without ever lifting a finger—or, in this case, a jar lid. Scientists have unlocked a groundbreaking way to analyze centuries-old specimens sealed in glass jars, all without risking damage to these irreplaceable treasures. But here’s where it gets even more fascinating: they’re using lasers to do it, achieving a staggering 95% accuracy in identifying the chemicals inside. This isn’t just a cool tech trick—it’s a game-changer for preserving history and protecting both science and people.
For centuries, natural history museums have housed millions of specimens preserved in fluids, some dating back nearly 200 years. Many of these jars contain mysterious or poorly documented chemical mixtures that could be toxic or harmful if disturbed. And this is the part most people miss: among these treasures are specimens collected by Charles Darwin himself during his voyage on the HMS Beagle—artifacts that continue to shape our understanding of evolution. Until now, identifying the preservation fluids meant opening the jars, risking evaporation, contamination, or irreversible damage. But a new laser-based technique is changing the game.
Researchers have developed a method called spatially offset Raman spectroscopy (SORS), which uses lasers to analyze the chemical makeup of fluids through the glass itself. By studying how light scatters after passing through the container and liquid, scientists can determine the composition of preservation fluids without ever breaking the seal. This approach has already been tested on 46 sealed specimens, including fish collected by Darwin, mammals, and invertebrates, with remarkable success.
Here’s the kicker: the technique not only identified the preservation fluids in nearly 80% of cases but also provided partial identification in 95% of them. But here’s where it gets controversial: the study revealed that preservation methods varied widely across species, with mammals and reptiles often treated with formalin before being stored in alcohol, while invertebrates were preserved in formaldehyde or mixed solutions containing additives like glycerol. This raises questions about the long-term stability of these chemicals and the potential risks to both specimens and conservation staff.
The implications are huge. For curators, knowing what’s inside these jars helps them make informed decisions about preservation and reduces risks to their teams. For historians and scientists, it means maintaining the integrity of specimens that have shaped our understanding of the natural world. And this is the part that should spark debate: as we uncover more about these historic preservation methods, should we reevaluate how we handle and store aging collections? Are we doing enough to protect both the science and the people who study it?
Sara Mosca, from the Science and Technology Facilities Council’s Central Laser Facility, puts it bluntly: “This technique allows us to monitor and care for these invaluable specimens without compromising their integrity.” Chelsea McKibbin, a senior conservator, adds, “These specimens represent 200 years of scientific collecting, including Darwin’s original samples. Being able to analyze them without opening their containers ensures they remain available for future generations.”
Beyond Darwin’s collection, this approach could revolutionize how museums worldwide manage their wet collections, offering a safer, non-invasive way to preserve irreplaceable biological records. The study, published in ACS Omega, is just the beginning. But here’s the question we’re left with: as technology advances, how far should we go to protect the past? And what responsibilities do we have to ensure these treasures—and the people who study them—are safeguarded for generations to come?
Let us know what you think in the comments. Are we doing enough to preserve history, or is there more we could—and should—be doing?
