Yet another example of why we should be careful about accepting all such statements, even ones containing a good source reference.
Not everyone has the time and resources to check such quotes, so let me suggest that the place of greatest danger will be found in a statement that fits neatly with what we already believe -- i.e., we want it to be true.
It's one thing to do what Dr. Mary Lefkowitz did at Wellesley College in the early nineties. For those who are unfamiliar with her efforts to debunk a widely-accepted academic fraud, here's a link --
http://www.historyplace.com/pointsofview/not-out.htm
It's another to examine our own cherished theories and stories that we deeply want to believe to determine what's true and what's not.