For instance, who, in 1911, could have predicted all the consequences
of the pistol-shot at Sarajevo? Who, even today, can guess what the
history of the world would have been had Zangarra not missed Franklin
Roosevelt in 1932? There's always that if."

He went on talking safe generalities as he glanced covertly at his
watch. Only five minutes to the end of the period; thank heaven he
hadn't made that slip at the beginning of the class. "For instance,
tomorrow, when we take up the events in India from the First World War
to the end of British rule, we will be largely concerned with another
victim of the assassin's bullet, Mohandas K. Gandhi. You may ask
yourselves, then, by how much that bullet altered the history of the
Indian sub-continent. A word of warning, however: The events we will
be discussing will be either contemporary with or prior to what was
discussed today. I hope that you're all keeping your notes properly
dated. It's always easy to become confused in matters of chronology."

He wished, too late, that he hadn't said that. It pointed up the very
thing he was trying to play down, and raised a general laugh.

As soon as the room was empty, he hastened to his desk, snatched
pencil and notepad. This had been a bad one, the worst yet; he hadn't
heard the end of it by any means. He couldn't waste thought on that
now, though. This was all new and important; it had welled up suddenly
and without warning into his conscious mind, and he must get it down
in notes before the "memory"--even mentally, he always put that word
into quotes--was lost. He was still scribbling furiously when the
instructor who would use the room for the next period entered,
followed by a few of his students. Chalmers finished, crammed the
notes into his pocket, and went out into the hall.