I was sure I’d included this story here at some point in the past, but I went looking for it yesterday and couldn’t find it. Therefore, I now pass along the following story from Mark Twain’s autobiography, as edited by Charles Neider, pg. 256:
Doctor John [Brown] was very fond of animals, and particularly of dogs. No one needs to be told this who has read that pathetic and beautiful masterpiece, Rab and His Friends. After his death his son, Jock, published a brief memorial of him which he distributed privately among friends; and in it occurs a little episode which illustrates the relationship that existed between Doctor John and the other animals. It is furnished by an Edinburgh lady whom Doctor John used to pick up and carry to school or back in his carriage frequently at a time when she was twelve years old. She said that they were chatting together tranquilly one day, when he suddenly thrust his head out of the carriage window eagerly—then resumed his place with a disappointed look on his face. The girl said: “Who is it? Some one you know?” He said, “No, a dog I don't know.”
I know exactly how he felt.