A pre-historic blood stain that is believed to be over 6000 years old was found by a team of archaeologists led by Prof.Raj Somadeva who is trailing the prehistoric civilisation that existed in Sri Lanka thousands of years ago.
The Sunday Observer interviewed Prof.Somadeva on the importance of this discovery and the progress of their research including what interesting conclusions they might make based on this latest discovery.
Excerpts of the interview
Q. There has been a discovery of prehistoric blood stains in Lunugalge cave excavations. What is the importance of this discovery?
A. We have recovered a small quartz flake (6x4cm) on which was observed a stain on one of its surfaces. It was at the excavation conducted by me and my students in a cave situated in the Village Illukkumbura of Balangoda. This stone flake was identified as a prehistoric stone implement. We were curious about the stain and separated the flake quickly from the other artefacts excavated, for further investigations. Initially we thought it was a colour stain as a result of a certain mineralization process which had occurred on the surface of this stone over a long period. But we were lucky at that time because when this object was noticed on the excavated soil, one of our students, Dr.Sankha Randeni Kumara (MBBS) was with me and I asked him to handle the packing and storing of it carefully. When I returned from the field I asked one of my colleagues in the Sri Lanka Institute of Nano Technology, Dr.Gamini Piyadasa to help me to make a few high resolution micrographs of this colour stain. I knew at that time he was closely working with high resolution microscopes. On my request Dr.Piyadasa introduced me to Keerthi Wickramarathne in the Medical Research Institute, Borella and finally the Director of the MRI was generous to help me. Following these communications, Wickramarathne has taken 21 photographs of the colour stain through the Scanning Electron Microscope (SEM). The photographs suggest that the colour stain was not a representation of a mineral pigment. It shows a close resemblance with microscopic structure of a bodily fluid. The cytomorphological characteristics found in the colour stain are explicit in the SEM image suggested that it is a remnant blood stain.
Q. How did you decide it represented a blood stain of human origin?
A. No I am not in a position to make such a professional decision independently. It should be identified by the professionals of the respective disciplines. Our sample is a very old specimen. The date we obtained to the charcoal collected from the soil layer where the stained stone implement was found, through the AMS method, goes 4500 years back in time. Most of our professionals in haematology were trained in handling modern specimens but not the samples of such an early date. I suppose that this is a new experience for them also. The comparative analysis of the SEM images of our sample with the published SEM images of prehistoric human blood stains reported from the other sites in the world proposes close similarities in their cytomorphology.
For instance, according to Mary Louise Turgeon (2004), atypical human red blood cell has a disk diameter of approximately 6.2–8.2 µm. The disk diameter of the two erythrocytes identified in the SEM image of our sample is 5.9 µm. This size reduction might have resulted by the contraction of the cell due to the prevailing dryness.
But this is not adequate to scientifically confirm the authenticity of its human origin. Therefore we need more rigorous analysis to meet such standards; the work is still in-progress. We are planning to obtain several Atomic-force Scanning Electron micrographs to test the chemical properties of the composition of the stain.
Perhaps it also may not be successful due to the extreme dry condition of the sample. The most successful method recently developed in the world to analyse the ancient blood stains is called radioimmunoassay. It was introduced by Dr. Jerold M. Lowenstein, a Clinical Professor of Medicine at the University of California at San Francisco. I do not think that we have a technical facility to such a modern test in Sri Lanka.
Q: Do we have the technology to test and analyse these samples here or are you planning to send them overseas?
A. I have no idea about whether we have other appropriate techniques available in Sri Lanka to analyse such an old sample. Even abroad, experts on ancient blood studies are extremely rare.
The only authoritative person I know is Professor Policarp Hortolà Rovira of Virgili University & Catalan Institute of Human Palaeoecology and Social Evolution in Spain. He is working on a sub-discipline called Haemotaphonomy and has extensively published his findings. If I failed to find a suitable place and a person to analyse our present sample I have to look for another alternative.
Q: Is the stone instrument on which the blood was discovered, a weapon? what may have been the circumstances of his/ or her death, is it possible that he had been killed?
A. I don't know. The blood stain is visible only on one surface of the implement. This observation suggests that the implement had not penetrated into a bodily fluid. If it had penetrated into such a medium blood should be on both surfaces. What we could hypothesize is that someone had purposefully smeared blood on the implement. Any argument raised on the underline purpose of such an act is mere imagination. Prehistoric stone implements are a kind of utility objects which the hunter-gatherer communities used to meet their daily needs such as cutting, chopping drilling etc. There is a possibility of the use of such an implement as a weapon to harm someone. In this case I do not think something like that could have happened in that cave, especially with reference to the stone implement under study.
Q:What are the important findings of recent excavations at Lunugala and other sites? How long will it take you to wrap up the research?
A. We found a considerably rich assemblage of charred floral remains representing several different floral species. More interesting is a few seeds in the assemblage that could be identified as wild rice (Oriza sp.).This is the findings of wild rice from such an old date which has been reported for the first time. I asked the help of the Plant Genetic Resource Centre(PGRC) in Gannoruva to carry out a research on the sample. I am greatly indebted to Dr. W.L.G. Samarasinghe, Additional Director of the PGRC to show his generous support to conduct the analysis on our sample. We are expecting the results soon.
We are seeking to address an important question pertaining to the development of the early history in Sri Lanka. It is the question of the continuity of the traditional hunter-gatherers towards the historical period. I believed that there was a transition and it would have been a complex process than we think. We are interested to understand how the prolonged occupation of the prehistoric-hunter-gatherers has interacted with the iron using communities at the dawn of the historical period.
We initiated this research program in 2007 and initially planned for 15 years. Now we are at the halfway. More scientific dates are needed to test our hypothesis. The existing material database should be expanded to outline the continuities and changes of the complex process that I mentioned. It is my duty to mention the funding agencies of this research program. Postgraduate Institute of Archaeology of the Kelaniya University and the National Science Foundation in Sri Lanka are the major contributors and also the Yuga Vimasuma organization in Colombo.