"What a child he was!" Glance, in the first place, at that famous temperament of his. Perhaps the best impression we have of it is one written by his friend Joseph Twitchell in a letter from Switzerland where they were tramping together in 1878. Mark Twain was forty-three at the time. "Mark is a queer fellow," says Twitchell. "There is nothing that he so delights in as a swift, strong stream. You can hardly get him to leave one when once he is within the influence of its fascinations. To throw in stones and sticks seems to afford him rapture. To-night, as we were on our way back to the hotel, seeing a lot of driftwood by the torrent side below the path, I climbed down and threw it in. When I got back to the path Mark was running down-stream after it as hard as he could go, throwing up his hands and shouting in the wildest ecstacy, and when a piece went over a fall and emerged to view in the foam below he would jump up and down and yell. He said afterward that he hadn't been so excited in three months. He acted just like a boy." And observe what he said of himself in "The Turning-Point of My Life": "By temperament I was the kind of person that _does_ things. Does them and reflects afterward. So I started for the Amazon without reflecting and without asking any questions. That was more than fifty years ago. In all that time my temperament has not changed, by even a shade. I have been punished many and many a time, and bitterly, for doing things and reflecting afterward, but these tortures have been of no value to me: I still do the thing commanded by Circumstance and Temperament, and reflect afterward." One could hardly ask for a more perfect definition of immaturity.