My wish to go to Berlin arose partly from a desire to hear Bopp, but yet more from a desire to make the acquaintance of Schelling. My inclination towards philosophy had become stronger and stronger; I had my own ideas about the mythological as a necessary form of ancient philosophy, and when I saw that the old philosopher had advertised his lectures or lecture on mythology, I could not resist, and went to Berlin in 1844. I must say at once that Professor Bopp, though he was extremely kind to me, was at that time, if not old—he was only fifty-three—very infirm. In his lectures he simply read his _Comparative Grammar_ with a magnifying glass, and added very little that was new. He lent me some manuscripts which he had copied in Latin in his younger days, but I could not get much help from him when I came to really difficult passages. This, I confess, puzzled me at the time, for I looked on every professor as omniscient. The time comes, however, when we learn that even at fifty-three a man may have forgotten certain things, nay, may have let many books and new discoveries even in his own subject pass by, because he has plenty to do with his own particular studies. We remember the old story of the professor who, when charged by a young and rather impertinent student with not knowing this or that, replied: “Sir, I have forgotten more than you ever knew.” And so it is indeed. Human nature and human memory are very strong during youth and manhood, but even at fifty there is with many people a certain decline of mental vigour that tells chiefly on the memory. Things are not exactly forgotten, but they do not turn up at the right time. They just leave a certain knowledge of where the missing information can be found; they leave also a kind of feeling that the ground is not quite safe and that we must no longer trust entirely to our memory. In one respect this feeling is very useful, for instead of writing down anything, trusting to our memory as we used to do, we feel it necessary to verify many things which formerly were perfectly clear and certain in our memory without such reference to books.