Eugenics, which had started long before my time, had once been defined as including free love and prevention of conception... Recently it had cropped up again in the form of selective breeding. Margaret Sanger
The problem of defining exactly what is meant by the signal velocity, which cropped up as long ago as 1907, has not been solved. Hans Christian von Baeyer
Jewishness cropped up and has never successfully been put down since. P. J. O'Rourke