Physical and histological investigation of the embalmed skin: application to some Egyptian mummy heads from the Marro collection (Turin)

The work will discuss the materials employed in the mummification of some Egyptian Dynastic embalmed heads (VI – XI Dynasty) and is the summary of a lot of studies performed in this framework in the last two years. The samples are skin fragments removed from mummified heads belonging to the “Giovanni Marro” collection, developed by Professor G. Marro between 1907 and 1913, at the necropolises of Asiut (the old Lycopolis), 380 km south of Cairo, and of Gebelein 28 km south of Luxor (the ancient Thebes), during three of the archaeological campaigns of the Italian Archaeological Mission. The collection is curated at the Museum of Anthropology and Ethnography of the University of Turin. The present work takes part in the number of activities promoted by the Museum for management and conservation of the stored ancient remains [1]. Several physical techniques were employed to detect and analyze the traces of the embalming materials on the mummified remains. FTIR spectroscopy was applied on samples prepared as KBr pellets and allowed to gain information both on the embalming substances spread on the skin and on the preservation state of the skin from the analysis of the characteristic bands of the cutaneous tissue. Micro-FTIR spectroscopy (beam light area about 0.4×0.4 mm2) was employed to identify the chemical nature of the materials on the skin surface and to measure the embalming substance penetration in the skin by focusing the IR beam on tissue layers at different depth. The results were compared with the histological measurements. Skin fragments were Mayer’s hemalum and eosine stained and revealed some brownish-yellow bands inserted among the bluish collagen fibers which may be attributed to the embalming substances soaked through the skin surface. ATR spectroscopy was applied to water and ethanol extracts of one of the embalmed skin samples. Several embalming substances were tested by matching the IR spectra against a library of diagnostic markers and the excellent superposition of the propolis spectrum supports the hypothesis that one of the embalming substances could have been beeswax (Fig. 1) [2], [3]. Finally, SEM images of some skin fragments showing Natron encrustations will be shown, supplied by XRD analyses.[1]R. Boano, D. Meaglia, G. Dutto, E. Costa, and E. Rabino Massa (2011): The biological archive of the Museum of Anthropology and Ethnography of Turin: microscopic analysis to assess the preservation of ancient human hair, in Yearbook of Mummy Study, Vol. 1, eds. H. Gill-Frerking, W. Rosendahl & A. Zink and D. Piombino Mascali, pp. 29-32. [2] S. A Buckley, K. A. Clark, and R. P. Evershed (2004): Complex organic chemical balms of Pharaonic animal mummies. Nature 431: 294-299. [3] C. Stani, A. Baraldi, R. Boano, R. Cinquetti, and M. G. Bridelli (2014) Study of skin degradation in ancient Egyptian mummies: complementarity of Fourier Transform Infrared Spectroscopy and histological analysis. J. Biol. Res. 87: 2133, 26-28.