Such abuses occur chiefly in connexion with fabulous stories and are sometimes carried to ludicrous or even scandalous extremes: for in such cases the more unscrupulous commentator has such full scope for invention, that he can tell lies to his heart's content about whole books and authors without fear of detection: for what never existed can obviously never be found, whereas if the subject is familiar the careful investigator will often detect the fraud. Consequently I shall count it a merit in a teacher of literature that there should be some things which he does not know.