Analysing the smell of corpses may help to find the dead—and the living

IT IS morbid, but true, that one of the ways survivors of natural disasters are found is by bringing out bloodhounds that have been trained to find the dead. Often, when these dogs reveal corpses under rubble, rescuers also find previously undetected air pockets with living people in them. Dogs are useful when police officers are looking for the buried corpses of murder victims, too. Such animals, however, require feeding and housing when they are not being used, and expert handling when they are. It might be better, therefore, if they could be replaced by machines—and that is what Sarah Jones and Dan Sykes of Pennsylvania State University propose to do. As they outlined to this week’s meeting of the American Chemical Society, in Washington, DC, they have been analysing the smell of corpses, with a view to automating the process of detecting them.

The idea of doing this is not entirely new, but when Ms Jones and Dr Sykes looked at the previous studies they found that the corpses used were usually at least three days old. That is an almost inevitable delay if human cadavers are employed, since permission must be sought and forms filled in. But the two researchers wanted to know which chemicals emanate from freshly dead bodies, as well as from those that have been around for a few days. So they decided to compromise and work on pigs instead of people. Pigs are often used as substitutes for humans in early-stage medical experiments, as they are about the same size. For that reason, too, they decay at the same rate and go through the same phases of decomposition. …