Lettuce and several other vegetables began as weeds. So did penecillin, in a sense. Until Fleming, or the people who we have to thank for lettuce, many had already rejected these well-disguised blessings, and comfortably labelled them

INSIDIOUS INVADER

.
The genius of Fleming, as my godfather loves to tell me: Fleming encountered the same insidious invader on his petri dish that many intelligent scientists before him had seen and discarded immediately, mourning their ruined cultures. But Fleming saw something different. Something powerful. Something important.
We must work hard to bring lettuce out of the weeds.

Most importantly, we must look sharply. With new eyes.