In modern pharmacology it's so clear that even if you have a fixed dose of a drug, the individuals respond very differently to one and the same dose.
“But, gentlemen, can any of us say that as a result of such overwhelming sacrifices of money, of men, of ideals, and of civil dignity the sense of security has indeed been attained?”
“The groundhogs are pretty good at eluding. If somebody is trying to come after a ground hog, they go and they burrow.”