I was reading about the myth of the Hydra, and I read the part about how Hercules calls up his pal Iolaus, who uses a hot iron or torch to stop the Hydra's heads from growing back after Hercules cut them off. I did some basic research on Google and found that in the Middle Ages and possibly earlier, doctors would pour boiling oil onto wounds to stop the bleeding, but could not find much else. However, the mention of a "hot iron" being used to stop the Hydra's head from growing back would imply that the Greeks or Romans had some knowledge of using tools to cauterize wounds. Was this true? If so, to what extent did Greek or Roman doctors (or whatever the equivalent is) know about cauterization and how often was it used?