Probably no one would have cared very much a couple of hundred years ago if toads were constantly present in the centre of solid stones. Toads were regarded as queer, dangerous things connected with witchcraft, and there was no accounting for their behaviour. The view taken by the well-to-do class would have been in those days (as perhaps it would be less generally to-day) similar to that of the Chicago millionaire when shown, by means of the spectroscopic examination of light, the proof of the existence of the metal sodium in the sun. The professor who took the millionaire round his laboratory wished to interest him in the discoveries of science, and hoped that he might contribute to the funds necessary to pay for the elaborate and delicate instruments by which such discoveries are made. He showed many remarkable experiments to his visitor, and wound up by showing him the two narrow lines of yellow light caused by incandescent sodium. He showed him how exactly their position in the spectrum could be fixed and measured; how they caused two black lines in the spectrum of light, which was made to traverse a flame in which incandescent sodium was present. And then he showed him that in the spectrum of the sun's light there were two black lines (besides thousands of others) which exactly coincide with the two sodium lines; whilst others of the black lines in the solar spectrum coincide with bright lines given out by incandescent hydrogen, iron, magnesium, etc. The millionaire followed it all and understood the completeness of the demonstration. The professor was delighted and hopeful. Then the millionaire said, "Who the hell cares if there is sodium in the sun?" I was not told by the disappointed professor (it was Professor Michelson, and he related this little episode at a dinner of the Royal Society) what reply he made to this inquiry or whether he was eventually successful in his attempt to secure funds from the millionaire. The attitude which the millionaire took towards scientific discovery is not a natural one, but the result of the stifling of natural interest and curiosity by long concentration on the art and practice of money-making. So, too--owing to other mental pre-occupations and concentrations--though a boy or a savage might have been puzzled and deeply interested in the occurrence of a live toad in the middle of an apparently solid piece of rock, the "country gentleman" of the eighteenth century would have said, if the matter had been pressed on his attention, "Who the hell cares if there are live toads in the rocks?" And a large but decreasing number of his representatives to-day would make the same remark.