A French doctor has completed the first-ever artificial blood transfusion after extracting stem cells from a patient's bone marrow, which were then used to grow the red blood cells under laboratory settings. "After five days, 94 to 100 percent of the blood cells remained circulating in the body. After 26 days, 41 to 63 percent remained, which is a normal survival rate for naturally produced blood cells." The cells carried oxygen throughout the patient's body, just as normal red blood cells would.