Discovered more about the circulation of blood , could get blood to move around a lump to reduce the need for amputations , worked on cancer, 1767- experimented on himself with gonorrhea , and demanded careful observation , he tried radical surgery in 1785 he saved a man’s leg with a throbbing lump (aneurysm) on his knee join, instead of removing the whole leg, found out ways of preventing amputations and proved importance of experiments observation and recording , encouraged other surgeons to complete experiments to find new info and spread his ideas through his books