To collect something or another, stamps, coins or butterflies, is a universal pastime, and it needs no explanation or excuse save the satisfaction which it brings. One may play the same game in another way, by collecting information; but the facts which one accumulates must be remote from one's duty and avocation. An old scholar taught me the game more than fifty years ago and I have never stopped playing it; it is such an easy and so engrossing a game. You choose some subject or other which takes your fancy; you buy a note-book and label it with the title of your theme; and you keep jotting down therein whatsoever bears upon the subject, as it comes your way, in all your reading, observation and reflection. I have had many such note-books, and some I have soon grown tired of; but others have lasted long and served me well. One of these is called De Ludis Antiquorum; it is grown old and shabby, for I played with it during many years. Your subject opens out wonderfully as time goes on; it tempts you into by-ways, it carries you afield; if you play the game aright it never comes to an end. It grows in interest continually, for things are interesting only in so far as they relate themselves to other things; only then can you put two and two together and tell stories about them. Such is science itself and such is all the knowledge that interests mankind.