In Baltimore, 1950. A 5-year-old boy named Kenneth “Kenny” H. was dying. He had been born with a hole in his heart — a condition called tetralogy of Fallot. In 1950, it was a death sentence. No child had ever survived the surgery. Most doctors would not even attempt it.

A surgeon named Dr. Alfred Blalock — one of the pioneers of cardiac surgery — decided to try. He had performed this surgery on adults. Never on a child. He was not sure the child’s heart would survive the incision. He was not sure the child would survive the anesthesia. He was not sure of anything.

The surgery was scheduled for 6:00 AM on May 20, 1950. Dr. Blalock asked for a nun — a woman named Sister Mary Bernard — to be in the operating room. He was not a religious man. But he thought: “If this child dies, someone should pray. Someone should be there who believes in something more than scalpels.”

Sister Mary Bernard stood in the corner of the operating room for 9 hours. She held her crucifix. She prayed. She did not stop. Not when the scalpel slipped. Not when the blood pressure dropped. Not when the child’s heart stopped — twice. She prayed.

Dr. Blalock opened Kenny’s chest. He cut through the breastbone. He exposed the heart. The hole was larger than he expected — the size of a dime in a heart the size of a walnut. He had planned to sew it closed. He could not. The tissue was too thin. It would tear.

So Dr. Blalock did something no surgeon had ever done. He took a piece of the lining from Kenny’s own heart — the pericardium — and used it to patch the hole. He sewed it with stitches so fine that he could barely see them without a magnifying glass.

At 3:00 PM, Dr. Blalock closed Kenny’s chest. The heart was beating. Weak. But beating.

Kenny woke up 6 hours later. He looked at his mother. He said: “I saw an angel. She was wearing white. She was praying.”

The surgery was a success. Kenny survived. He grew up. He went to college. He became a doctor — a cardiologist. He saved hundreds of children’s lives. Children who would have died without the surgery that he had been the first to survive.

Dr. Blalock died in 1964. On his deathbed, he said: “The surgery was not my success. It was the child’s. And the nun’s. She never stopped praying. I stopped believing twice. She never did.”

Sister Mary Bernard died in 1998. She was 94 years old. She had prayed in that operating room for thousands of hours over her lifetime. But she always said the 9 hours on May 20, 1950, were the most important hours of her life.

Kenny H. — Dr. Kenneth H. — died in 2019. He was 74 years old. He had outlived everyone who saved him. At his funeral, his daughter read a letter he had written before he died. The letter said:

“I owe my life to a surgeon with a steady hand and a nun with a steady faith. One cut. One prayed. Together, they built a heart. Mine. Now I give it back. Use it. Save someone else.”

The question that Dr. Kenneth H. asked at every medical conference he attended for 40 years: “If science and faith can work together to save a 5-year-old boy, why do we spend so much time pretending they are enemies?”