I had, also, during many years followed a golden rule, namely, that whenever a published fact, a new observation or thought came across me, which was opposed to my general results, to make a memorandum of it without fail and at once; for I had found by experience that such facts and thoughts were far more apt to escape from the memory than favourable ones. Owing to this habit, very few objections were raised against my views which I had not at least noticed and attempted to answer.

-From his Autobiography, 1902.

A wonderful quote indeed. Found by guessing that it was biographical or autobiographical (it seemed a little too personal for a scientific treatise) and searching for the word "fact" in the online text of the (very readable) autobiography.