Scientific Article for Students

Introduction Have you ever been to a museum and seen a sarcophagus? Sometimes they have mummified bodies inside! Mummified bodies from ancient Egypt are fascinating. They can show us what ancient civilizations were like. They can tell us things about people’s health and their religious practices. ***** Explainer box: ‘Mummified bodies’ are also known as ‘mummies’. We used this term in our title! However, researchers prefer to use the term ‘mummified bodies’. This is to show that a mummy was a person and helps us remember to treat them with respect. **** The transition into the afterlife was very important in ancient Egypt. This required preservation of the person’s body. This process is called mummification. The process uses a lot of natural materials. For example, they used resin and oils from pine, cedar, and juniper trees. They also used bitumen, spices, herbs, and waxes. These materials can have strong smells. And it was important to smell good for the afterlife! Unfortunately, studying mummified bodies is hard. They are old and many are in bad condition. Scientists also need to be aware of ethical and cultural concerns for dead bodies. Ideally, we should study mummified bodies non-invasively, without even touching the body. One way to do this is by exploring what mummified bodies smell like. Smells can give us lots of information about museum artifacts. They can help identify what artifacts are made from. They can help track how materials break down over time. They can even help discover what was done to conserve and restore artifacts. We had several questions. What do ancient Egyptian mummified bodies smell like? Can we tell what materials were used in the mummification process? How much have the bodies broken down? How were they preserved? So, we explored the smells of mummified bodies from Egyptian museum collections. Methods We examined nine mummified bodies from the Egyptian Museum in Cairo. Four were in display cases and five were in storage. They were from different time periods. They were also made of different materials. And they had different preservation histories. We did two analyses: Smell analysis – We created a set of 13 descriptions of smells. These were things like “woody”, “sweet”, and “floral”. Then we trained five volunteers and, along with three trained panelists, we assessed these smells and their intensity. They also rated if the smell was pleasant or not. We collected air from around the mummified bodies or from their display sarcophagi (Fig. 1a). Then we had the volunteers sniff the air and identify what they smelled. Compound analysis – We used gas chromatography-olfactometry-mass spectrometry instruments (Fig. 1b) to help us. First, gas chromatography separates an air sample into individual compounds. Air that contains each compound is then split into two streams. One stream goes to the mass spectrometer. This helps identify the compounds. At the same time, the other stream goes to a trained human “sniffer”. They describe the smell, intensity, and pleasantness of each compound. We can then match the compound with what it smells like! We used this process for air collected from all nine of our mummified bodies. Results We found that mummified bodies mostly smelled pleasant. The most common smells volunteers identified were “woody” (78%), “spicy” (67%), and “sweet” (56%). They also sensed big differences in smell intensity (see Figure 2 on p.3). We found that the overall smell of the mummified bodies wasn’t always the same as the individual compounds. Using our instruments we found that smells were more intense from mummified bodies in display cases. We also saw that mummified bodies from the Late Period (664-332 BCE) had similar smells. We found that smells came from four different things: materials used during mummification and when bodies broke down, microbes, oils to prevent pests, and synthetic pesticides. Discussion We can learn a lot by smelling mummified bodies! Our compound analysis gave us extra insights. For example, we found a lot of terpenoid compounds. These come from plants used during mummification. Mummified bodies from the same time period also have similar smells. More samples might let us use smells to figure out how old mummified bodies are. We were surprised to find synthetic pesticides. Their use wasn’t recorded in any conservation reports! Examining the smells of museum artifacts is not very common. But it can help us be safe when we work with artifacts. Smells caused by fats breaking down or by microbes can tell us when mummified bodies decompose. This could help scientists better store and wrap mummified bodies. We can also protect museum workers by identifying pesticides or other toxic compounds. And our methods ensure that we can do this non-invasively! Smell is an important part of human sensory perception. Smelling something can make interactions with ancient artifacts more significant. This can make museums more interesting and informative. In the future, we would like to make smells closely resembling those of ancient Egyptian mummified bodies. Future museum-goers will be able to experience the smells of mummification! Conclusion Do you have a favorite smell? For humans, we use sight and touch more than smell. But smell is an important part of our sensory perception. It can tell us that dinner is ready or if there is a fire. The next time you go somewhere new, try to use your sense of smell. What do you smell? Are there strong smells? How do the smells make you feel? You might be surprised at what you notice!