You see, I consider that a man's brain originally is like a little emptyattic, and you have to stock it with such furniture as you choose. A fooltakes in all the lumber of every sort he comes across, so that the knowledgewhich might be useful to him gets crowded out, or at best is jumbled up witha lot of other things, so that he has difficulty in laying his hands upon it.Now the skilful workman is very careful indeed as to what he takes into hisbrain-attic. He will have nothing but the tools which may help him in doinghis work, but of these he has a large assortment, and all in the most perfectorder. It is a mistake to think that that little room has elastic walls andcan distend to any extent. Depend upon it there comes a time when for everyaddition of knowledge you forget something that you knew before. It is ofthe highest importance, therefore, not to have useless facts elbowing outthe useful ones.
-- Sir Arthur Conan Doyle, "A Study in Scarlet"
