In 1868, while re-examining a preserved sample of mud he had collected several years earlier from the Atlantic seafloor, biologist Thomas Henry Huxley noticed that it now contained a transparent, gelatinous slime surrounding the remains of algae. Huxley thought he had discovered a new organic substance, which he named Bathybius haeckelii in honour of German biologist Ernst Haeckel, known for his theory of Urschleim (“primordial slime”), a protoplasm from which all life had presumably originated. Huxley believed Bathybius could be that protoplasm, a missing link between inorganic matter and organic life. He went on to assume that the substance formed a mat of living protoplasm covering the ocean floor for thousands of square miles, probably in a continuous sheet around the Earth. However, the marine research of 1872 discovered no such thing and soon after, Bathybius haeckelii was unequivocally proven to be nothing more than a reaction between calcium sulphate from the seawater and the alcohol used to preserve the original mud sample. The theory of primordial slime remains a scientific curiosity, yet was one of the early strong cases in support of an evolutionary origin of life from non-living chemistry to biology.
Meanwhile in the caves around the Earth, tiny droplets give rise to strange forms, organic in nature, but seemingly deliberate in design, reminiscent of insect dwellings and shells, or even human-made architecture. A liquid solution typically composed of mud, calcium carbonate, lava, tar or sand has the power to grow enormous rock formations known as stalactites and stalagmites. In its liquid state, the substance is an animator; in its hardened state, it is a surprisingly accurate record of past environmental conditions. In 2015, an accidental discovery by a young scientist Chris Myers, who was initially studying earthquakes in Tibet, saw him using the ratios of heavy to light isotopes of oxygen present in layers of stalagmite growth to track changes in temperature at which water originally condensed into droplets and in this way estimate prehistoric climates. A study of a cave in central India published the same year took the research further to show how it could provide a record of global climate warming that occurred between six to nine thousand years ago, as well as a model of how temperature anomalies might behave in the future. The material becomes a data carrier, increasingly more readable as the tools evolve—an archive of the evolution of life.
Under a gentle push of a finger, the surface of a laptop screen reveals the consistency of viscous crystalline slime. Liquid Crystal Display (LCD) technology can be traced back to physicist Otto Lehman and botanist Friedrich Reinitzer, the latter of whom having discovered the liquid crystalline nature of cholesterol extracted from carrots in 1888. As Reinitzer had no explanation for this aggregate state between liquid and solid, he involved Lehman, who at the time was studying properties of the iodide of silver. Lehman used a device of his own creation—a polarised light microscope—to establish that the deformation of crystal lattice structure is possible without using its crystalline properties. It means that in a mesophase, the substance can flow like a liquid, but its molecules have an order as in the crystal phase. Otto Lehman took over the research after Reinitzer’s initial discovery and was also the first one to refer to the new substance as liquid crystals. He was fascinated by Bathybius haeckelii and even speculated about characteristics of these liquid crystals as indicators of life. However, it wasn’t until the 1970s that the patents for using liquid crystal technology for controlling light were filed, dramatically shaping digital devices till the present.
In February 2021, an unusual type of Egyptian mummy was discovered—the remains of a woman had been encased in a mud shell, a cheaper and more easily available material than the embalming resin used on other mummified bodies. Ancient Egyptian embalming method was a lengthy, expensive process, only available to those with substantial wealth. Although Egyptians of moderate means undoubtedly had their own embalming practices, none of them survived the test of time—until now. According to Karin Sowada, the lead author of the research paper, the mixture of mud, sand and straw placed between the linen wrappings was most likely a later repair job on the damaged mummy. Nevertheless, it shows that the practice had been in use and possibly widespread. Bodily integrity was essential to ancient Egyptian beliefs about the afterlife, so the unattainability of efficient embalming practices for the general population effectively proclaimed that immortality was reserved for those of the upper class. With this discovery, mud plays a role in not just bodily but also cultural preservation, offering a wider, more inclusive picture of a long-gone human society.