The not-so-glamorous skill of examining bodies (mainly of the dead) to determine their medical history. Most often used in grim settings to determinethe cause of death and to reveal murder.
If you take the time to perform an autopsy, you can automatically identify the source of death and tell a lot about the dead person's last hours - level of activity, things he ate, if any violence was made upon him, if he had sex, things like that.
Identifying strange and/or unknown things may require a Medicine roll, but even a poor result will generally give you good clues.