【明報專訊】Mr Moon couldn't understand it at all. At his animal clinic, he had treated dogs and cats, and sometimes hamsters and guinea pigs, but never a mouse. It was a common house mouse rather than a special mouse. It was the sort of mouse people would try to catch with a trap or kill with poison. Mr Moon studied it closely. It was certainly more than three years old - very old for a mouse. It didn't try to escape from Mr Moon's hand, not because it wasn't afraid, but because it was very weak. "Listen," Mr Moon said to the woman who owned the mouse. "Let me end its life. It's old and weak." The visitor cried out, "No, no! You must keep it alive. I'll pay you as much money as you want. Please try!"