“You should deal sternly and despotically with your memory, so that it does not unlearn obedience; if, for example, you cannot call something to mind, a line of poetry or a word perhaps, you should not go and look it up in a book, but periodically plague your memory with it for weeks on end until your memory has done its duty. For the longer you have had to rack your brains for something the more firmly will it stay once you have got it.”