“I consider that a man’s brain is like a little empty attic, and you have to stock it with as much furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best jumbled up with a lot of other things so that he has a difficulty laying his hands on it… It is a mistake that that little room has elastic walls and can distend to any extent. Depend upon it there comes a time when for every addition of knowledge, you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.”