I am not prepared to accept these or any other limitations as to the books I shall possess and read, and yet I do want to urge the principle involved in them upon my readers. Learn to do your own thinking rather than take your thoughts at second hand from what some one else has written. At the same time I would urge upon you the reading of the writings of our great poets that you may absorb from them their love of Nature. In this way it may be that you will be won to the love and appreciation of that which you have never before known or enjoyed. Just as the artist on his canvas sets forth for us a beautiful scene out of the great world that surrounds us and thus focalizes our attention upon it, and teaches us to see the beauty which hitherto we had passed unobserved, so does the poet focalize our attention upon that which hitherto we had passed by and neglected. Let us read, therefore, by all means, but not as an end in itself. Let us read that thereby we may be stimulated to go out into Nature to see, feel, and absorb for ourselves. Many of the books that are "worth while" were written by men and women who have been close observers of Nature. It is by observation that we absorb the facts and lessons of Nature. Some of the most helpful and beautiful books have been written as the result of the exercise of this faculty combined with the reflection that always comes to the truly thoughtful. The sciences are based upon observation, and as soon as one becomes interested in any particular line of study it is amazing how many fascinating things begin to crowd upon his attention. The great scientist, Agassiz, said that he could find enough to thoroughly and completely fill the whole of a life of eighty years in as much as he could cover with his one hand. I have spent night after night with astronomers whose whole vocation was to study the heavens and learn the wonderful lessons revealed thereby. One of the happiest epochs of my life was to spend two months in the High Sierras of California with Joseph Le Conte, the great geologist, and his keen and trained eyes revealed to me things in Nature that I had never seen before, and life has ever since been richer and fuller because of the experience. Darwin studied the facts of development of plant and animal life until he wrote a book which has completely revolutionized the thought of the world. He spent years in studying the movements and influences upon the ground of the common earth-worm and showed us how great a friend to humanity is this apparently insignificant and useless creature. Sir John Lubbock, the eminent statesman and philosopher, busy with the affairs of city and nation, spent years in studying the actions and life of the tiny ant and has given us most fascinating accounts of what he saw with philosophical deductions therefrom.