I remember hearing an interview with James Lovelock years ago. He did research during WWII on the treatment of burns. His work required him to develop salves and then test them on burnt skin. To obtain a sample of burnt skin he was told to take a Bunsun burner to a live rabbit which he did, once – he didn't have the stomach to inflict such suffering twice. So instead he burnt his own arm and tested the salves on that. “Didn't it hurt?” asked the incredulous interviewer. “Only the first time,” he cheerfully replied. There's heart for you.