Last autumn I fell off a horse and on to a rock, and, in one of those millisecond moments that feels like a small eternity, cleverly managed to break my right arm. No great calamity, to be sure, nor in ordinary circumstances anything really remarkable, except for the fact that this was not the first time, nor even the second, that I had broken it. This was the third time that fate had chosen to smite my bone asunder, and by this time the evident vulnerability of my right humerus was getting to be, if I can be permitted a lame pun, distinctly unfunny.