When he was 14, James Harrison needed surgery. And as he would come to find out, he would also need a significant amount ofstrangers’ blood to survive it.After he had recovered and as soon as he became an adult, Harrison felt compelled to pay it forward, he said. For the next 60 years he suppressed his strong distaste for needles — he says he has never watched one go into his arm — and gave blood every few weeks at locations across Australia.Along the way, medical professionals made a stunning discovery: Harrison’s blood contained a rare antibody necessary to make a pioneering medication that officials at the Australian Red Cross Blood Service said had helped save more than 2 million babies from a potentially fatal disease.They said more than 3 million doses of Anti-D, as the medication containing Harrison’s blood is called, have been issued to mothers since 1967.On Friday, Harrison took his seat at Town Hall Blood Donor Center in Sydney for what would be his last donation. Medical officials at the Red Cross decided that at 81, their valued donor should stop giving to protect his own health.Video recordings of the episode show Harrison — known to some as "the man with the golden arm" — grasping a stress ball as four silver balloons danced above him. The balloons were shaped in the numerals 1 1 7 3 — representing the total number of times Harrison has given blood."The end of an era," Harrison, a retired railway administrator, said on Sunday from his home in New South Wales. "It was sad because I felt like I could keep going."The value of his contributions is hard to overstate.The Red Cross estimates that around 17 percent of Australian women who become pregnant need Anti-D injections to keep their babies healthy, and the injections can be made only from donated plasma, which, in Australia, comes from what officials describe as "a tiny pool" of around 160 donors who have the special antibody in their blood.Without the injections, babies with certain blood types that are different from their mothers’ can develop hemolytic disease of the fetusand newborn, a potentially fatal condition. Officials estimated that as of last month, Harrison’s blood had helped more than 2.4 million babies."I cry just thinking about it," Robyn Barlow, the program coordinator who recruited Harrison, told The Sydney Morning Herald.Harrison had been donating blood for more than a decade when researchers found him in the 1960s and asked him to become the first donor in what would eventually come to be known as the Anti-D program.His blood was exactly what they were looking for. His body naturally produces the antibody that prevents the hemolytic disease. Harrison said he was still not sure exactly why, but believes it might have something to do with theblood he received as a teenager."The Red Cross and Australia can never thank a man like James enough," said Jemma Falkenmire, a spokeswoman for the Australian Red Cross Blood Service. "It’s unlikely we will ever have another blood donor willing to make this commitment."Harrison has been widely praised and has received the Medal of the Order of Australia for his longtime support of the Australian Red Cross Blood Service and the Anti-D program. Falkenmire said researchers were even working on what they have called a "James in a Jar project," with the goal of synthetically creating a mixture of antibodies that matches what Harrison produces naturally.According to Falkenmire, medical professionals are able to stimulate production of the antibody in donors, but the process can lead to a flulike reaction. Complicating matters, she said, not every potential donor — even those with the right blood type — are able to create the antibody as Harrison can.On Sunday, Harrison said he had enjoyed meeting the mothers, nurses and others who had gone out of their way over the years to find and thank him.Even his daughter, Tracey Mellowship, was one of those to benefit from his blood."Thank you dad for giving me the chance to have two healthy children — your grandchildren," Mellowship wrote in a comment on a Facebook post about her father.Harrison deflected most of the praise with humor and humility."Blame me for the increase in population," he said.As for how he processes the idea that he has saved millions of babies, he said: "Saving one baby is good. Saving 2 million is hard to get your head around, but if they claim that’s what it is, I’m glad to have done it."