One morning in London I was eating potted tunny-fish at breakfast, and I soon felt that it was having an effect on me. My brain was clearer than it has ever been before or since. I understood things that had always puzzled me; and nothing was obscure. In fact, for about two hours I was a Man of Genius; and then I dropped down to my usual level. I made many inquiries about it afterwards, but without result until I came upon a man who had spent a couple of years at the Laboratory of Marine Zoology at Naples. He had himself felt odd after eating tunny-fish one day, and he knew of other cases. In his own case there was increased blood-pressure, especially in the brain, such as might arise from eating putrid meat. But he thought his fish was sound, and ascribed the effect to some unknown substance in a tunny. This tempts me to suggest a problem. The ancient Greeks were the cleverest people ever known, and they were always eating pickled tunny. Were they quite so clever before they reached the Mediterranean, and got this particular food?--Common trout were put into some of the New Zealand streams, and they became great fish, quite unlike their ancestors. Did something of the same sort happen to the ancient Greeks, in intellect though not in body? There is no denying the cleverness of the ancient Greeks; but I am sceptical about their beauty. They would never have talked so much of beauty, unless it had been rare. When people now-a-days go talking of the beauty of Greek Gods, they are thinking of the works of Pheidias and his successors. There is much charm in works of earlier date; but nobody can say quite honestly that the people in them are good-looking, much less that they are beautiful. Yet the nation cannot suddenly have changed its looks. I think it was that artists were getting more fastidious in their choice of models. This notion struck me forcibly in the spring of 1888. I rode over a great part of Greece; and I did it comfortably, taking a dragoman and cook, with mules to carry the baggage, and muleteers to tend the mules. When my little cavalcade went through a village, the people all came out to have a look at it; and I had a look at them. Most of them were very plain indeed; but at every second or third village there would be one or two people who looked like ancient statues come to life. If I had brought home pictures of these people, and said nothing of the rest, I should have given quite a wrong impression of the modern Greeks.