A poor boy who was selling clothes door-to-door to pay for his education was hungry and asked a woman for food. She brought him a large glass of milk instead of just water. Years later, when the woman fell gravely ill, the doctor who was called in to help, Doctor Howard Kelly, recognized her as the woman who had shown him kindness in the past. Although she survived, when she received the bill for her treatment, Doctor Kelly had written "Paid in full with a glass of milk" on it, showing how one small act of kindness can come back to help someone in the future.