Scientists have discovered a way to study original specimens from Charles Darwin’s famous Beagle voyage to the Galapagos Islands (1831-1836).
What’s even more remarkable is that they were able to test the samples without opening the nearly 200-year-old jars in which they were stored.
Study Darwin’s historical specimens
The study focused on 46 historical specimens held at London’s Natural History Museum. These included mammals, reptiles, fish, jellyfish, and shrimp that Darwin and other naturalists collected during early scientific expeditions.
The analysis revealed that preservation methods varied depending on both the type of organism and the length of time the specimen was stored.
For example, mammals and reptiles are often treated with formalin before being preserved in ethanol. However, invertebrates were preserved using a wider range of liquids, including formalin, buffers, or mixtures with additives such as glycerol.
Identification of storage solution
The researchers were able to accurately measure the presence of preservative fluid in about 80% of the specimens tested. In a further 15% of cases, this technology allowed partial identification.
This method also revealed whether the container was made of glass or plastic. This information helps scientists better understand how storage practices have changed over time.
This project was a collaboration between:
- Science and Technology Facilities Council (STFC)
- natural history museum
- Agilent Technologies
Scanning specimen bottles with portable laser technology
To perform the analysis, the researchers used a portable laser spectroscopy method called spatially offset Raman spectroscopy (SORS). This technique allows scientists to examine the chemical composition of storage solutions through the walls of sealed containers.
SORS works by shining laser light onto a bottle and measuring how the light changes as it is scattered and reflected. These subtle changes in wavelength reveal the chemical signature of the material within the container.
Originally developed at STFC’s Central Laser Facility, SORS is also used in airport security scanners around the world through Agilent Technologies.
Dr. Sarah Mosca of the STFC Central Laser Facility said:
“Until now, understanding what preservation solution was inside each bottle required opening the bottles, risking evaporation, contamination, and exposing specimens to environmental damage.
“This technology allows us to monitor and care for these precious specimens without compromising their integrity.”
New tools for museum collections
Museums around the world house more than 100 million specimens preserved in liquid.
For curators, knowing the exact chemical composition of preservation fluids is essential to monitoring the condition of these collections. Over time, the liquid can degrade or evaporate, potentially damaging the specimen.
The ability to analyze these liquids without opening the containers gives museum professionals a powerful new way to track the health of their collections and intervene before problems occur.
Transforming natural history research
Len Montgomery, Research Technician at the Natural History Museum, said:
“As part of NHM Unlocked, here at the museum we are able to analyze jars containing specimens without opening them or compromising their integrity.
“This research is the next step in the museum’s commitment to transforming the study of natural history.
“Analyzing the storage conditions of precious specimens and understanding the fluids in which they are stored can have a huge impact on how we manage our collections and preserve them for future research for years to come.”
This study ACS Omega Featured as an ACS Editors’ Choice on January 13, 2026.
