James Harrison, an Australian blood donor known as “The Man with the Golden Arm”, died this week aged 88. Harrison’s plasma contained a rare and precious antibody called anti-D, which is used to prevent a potentially fatal condition in newborns called rhesus disease. He began giving blood as soon as he turned 18 and didn’t miss a single fortnightly session until he hit the maximum donation age of 81. Doctors say he likely saved the lives of 2.4 million babies.