Dust and its Analysis

AMONG the latest developments in criminal science the rtanalysis of dusts is one of the most recent and interesting. The more one studies it, the more surprising it is to reflect that we have had to wait until the twentieth century to see such a simple idea applied-the deduction of the movements and environments of a suspected person from the dust collected on his clothes. For. the microscopic dusts which cover our clothes and our bodies are silent yet certain and reliable witnesses of each of our actions and contacts. I should mention that although we have made a particular study, at the Police Laboratory at Lyons, of this question of dusts, we came across the idea first of all in the works of Hans Gross and Sir A. Conan Doyle. In addition, the opportunity of putting it into practice was, if I may so express it, forced upon us. I shall describe presently a certain number of cases in which the analysis of dusts was demanded by the circumstances of the cases themselves. Indeed the study may be considered as an extension of the analysis of stains. A policeman is not like a medico-legist, limited to the examination of blood and tissues. He is called upon every day to determine an astonishing variety of substances which stain the clothes, linen or skin of a suspected person. Among these different stains mud usually takes a high place, and what is mud but congealed dust? Outside Lyons a number of criminologists have been