But, like a true philosopher, he was anxious, first, to subject his theories to the test of keen criticism. Free discussion was, he knew, the best friend to the true interests of science, and he resolved, therefore to invite about him the most learned persons then resident in the capital, and to meet them in his lecture room to state to them his opinions, and to hear their arguments in reply. He set about doing this in a peculiar manner, which he describes. “Thus debating in my mind, I decided to cause notices to be affixed to the street corners in Paris, in order to assemble the most learned doctors, and others, to whom I would promise to demonstrate, in three lessons, all I have learned concerning fountains, stones, metals, and other natures. And, in order that none might come but the most learned and curious, I put in my placards that none should have admission without payment of a dollar. I did this partly to see whether I could extract from my hearers some contradiction which might have more assurance of truth than the arguments I should propound; knowing well that, if I spoke falsely, there would be Greeks and Latins who would resist me to my face, and who would not spare me, as well on account of the dollar I should have taken from each, as on account of the time I should have caused them to misspend. For there were very few of my hearers who could not elsewhere have extracted profit out of something during the time spent by them at my lessons. Also, I put in my placards that if the things therein promised did not prove trustworthy, I would restore the quadruple.” The result of this experimental course was most successful. “Thanks be to God,” says the triumphant lecturer, “never man contradicted me a single word.” Of the character of the audience whom Palissy attracted around him in his museum (as he called his cabinet of natural history), on this occasion, we are fully informed. He has given a list of more than thirty of them, including many skilful physicians, celebrated surgeons, grand seigneurs, gentlemen, and titled ecclesiastics, also some of the legal profession, and others, who were drawn together by a common love of scientific research. These were no idlers, but an assemblage of the choicest students—a sort of Royal Society, instituted for the occasion—who sat listening to the self-taught philosopher, the wise and vigorous old man, who, illustrating his cases as he went on, by specimens of the things about which he spoke, turned his cabinet into a lecture-room, where he delivered the first course of lectures upon natural history ever given in the French metropolis, held in the first natural history museum ever thrown open to the public there. Supported by the favourable opinion of such judges—than whom he could not have “more faithful witnesses, nor men more assured in knowledge,” Bernard “took courage to discourse” of various matters concerning which he had attained a surprising degree of knowledge.