James Harrison is an Australian man who has made a significant impact on the field of medicine. He has a rare blood type known as Rhnull, which makes his blood extremely valuable for medical research and treatment. Harrison's blood is considered to be one of the most precious and unique in the world. His plasma has been used to develop life-saving medications for Rh-negative mothers and their babies, as well as for patients with hemolytic disease of the newborn. Harrison has been donating blood regularly since he was 18 years old, and his donations have saved an estimated 2.4 million babies from the risk of Rh incompatibility. His selfless contributions have earned him numerous awards and honors, including the Medal of the Order of Australia.

In addition to his blood donations, Harrison has also been an advocate for blood donation and has helped raise awareness about the importance of donating blood to save lives. Overall, James Harrison's golden arm has had a profound impact on the field of medicine and has saved countless lives around the world. His generosity and dedication to helping others have made him a true hero in the medical community.