In his book Written In Blood, Robert Coleman tells the story of a little boy whose sister needed a blood transfusion. She had a rare blood type which she shared with her little brother. The fact that he had recovered from the same disease two years earlier made the chances of success even greater. The doctor carefully explained all this to the little boy, pointing out that without the transfusion his sister would die.
“Would you be brave and give your blood to your sister?” the doctor asked. Johnny hesitated. His lower lip began to tremble. Then he smiled and said, “Sure, for my sister.” The two children were wheeled into the hospital room – Mary, pale and thin; Johnny, robust and healthy. He smiled at his sister, the watched as the blood travelled out of his body, down the clear plastic tube. Johnny’s smile faded, and as he lay there feeling weak he looked up at the doctor and said, “Doctor, when do I die?’
Johnny thought that giving his blood to his sister meant giving up his life. Yet because of his great love for her he was prepared to pay the price.
Source: quote excerpted from Robert Coleman, Written in Blood.