Relatives of modern humans may have created and used a sticky substance both as a glue and to treat their wounds, preempting modern medicine by as much as 200,000 years, a new study suggests. Researchers have known that Neanderthals used birch tar, a viscous substance derived from birch bark, to glue spear points onto handles in a process known as hafting. This substance has been found across Europe, and it served multiple purposes, including as some of history's oldest water sealant and Hubba