The diagnosis of drowning by quantitative and qualitative diatom analysis.

The reliability and applicability of quantitative and qualitative diatom analysis in the diagnosis of drowning has been evaluated. Water and organ samples of immersion cases reported in the area covered by the Department of Forensic Medicine of the London Hospital Medical College, were analysed using both light and scanning electron microscopy. Controls included organ samples of the bodies of people who died from natural causes and exclusion of contamination. Organ samples of both immersion and control cases were prepared by chemical digestion with concentrated nitric acid. Diatoms were present in the majority of samples of organs of both immersion and control cases but there was a significant quantitative difference between the number of diatoms in control and immersion cases. Qualitative analysis of water and organ samples of immersion cases supported the diagnosis of death due to aspiration of water in approximately a third of the total of bodies found in water. It has been suggested that the present analysis can be used as basic criteria for standardization of the diatom method.