Getting under the skin

Press, 27 September 1986, Page 20

Getting under the skin

From “The Economist,” London

Egyptian mummies preserve within their wrappings intimate details of life 3000 years ago. (Older ones fell apart; younger ones suffered from cut-priCe embalming.) Problem: unwrapping the embalmed body is destructive — and there are only so many mummies left to dismember. Solution: use medicine’s non-des-tructive techniques to “look” inside the bandages.

Computer-aided tomography (C.A.T.) scanners — the machines that are used to find tumours in patients — are being used on mummies. By rotating an X-ray source and an image receiver in opposite directions around the body, the archaeologist can home in on single layers of tissue. By continuously recording the images of one full rotation on film, they get a threedimensional image.

Using the X-ray image for navigation, scientists can then explore any interesting objects or organs inside the body using an endoscope. This is a narrow illuminated tube that is inserted through the body’s natural cavities. It can be pointed in any direction and any obstructions, such as fluid, can be sucked out through the tube. Tiny samples of tissue can be gathered along the endoscope’s path using forceps. Once out of the confines of the fragile body, the tissue can be explored in a number of ways. Stains which change colour according to the chemical make-up of tissues add details to the external picture of cells painted by an electron microscope. Dehydrated fluids are reconstituted in much the same way as packet soups, and the cells suspended in the fluid to be examined at leisure. The mummy’s face can be reconstructed by preparing plaster casts of the two halves of a skull. These are moulded together, and covered with standard thicknesses of “flesh” to pad out the face. Details of facial hair gathered by electron' microscopy complete the model. Forensic scientists have used this technique, plus one devised to finger-print mummies (by a rubber mould of available digits covered with eight layers of acrylic paint) to identify, more recent corpses made tinonymous by decay. The value of non-destructive techniques is that the secrets of the mummies no longer, hqve to be taken by force. Though many mummies are still .’ in Cairo’s museums, an international data base has been set up at the Manchester Museum in Britain to keep a permanent record of every mum’s secret. < Copyright, “The Economist.”