"Hormesis was well known by the ancients (and like the color blue was known but not expressed). But it was only in 1888 that it was first "scientifically" described (though still not given a name) by a German toxicologist, Hugo Schulz, who observed that small doses of poison stimulate the growth of yeast while larger doses cause harm. Some researchers hold that the benefits of vegetables may not be so much in what we call the "vitamins" or some other rationalizing theories (that is, ideas that seem to make sense in narrative form but have not been subjected to rigorous empirical testing), but in the following: plants protect themselves from harm and fend off predators with poisonous substances that, ingested by us in the right quantities, may stimulate our organisms--or so goes the story. Again, limited, low-dose poisoning triggers healthy benefits."