My favorite author, James Herriott, wrote a series of books detailing his life as a veterinarian in the Yorkshire dales of England during the 30's through the 60's. These are true stories. I remember at least two stories in which a cat was brought in, nearly fatally wounded, and Mr. Herriott was struck by the nearly dying cat's ability to continue purring loudly. Both these cats survived. Maybe this explains why!