Faraday's habit of testing opinions by experiment, and the frequent disillusions which he encountered with regard to things of which he thought he knew something definite, served to make him extremely careful as regards expressions of opinion. Some of his thoughts on this subject are worth while recalling because they remain perennially true, and anyone in any generation will find that, as his experience grows, he gets more and more into this Faraday mood of doubting his own opinion and listening with more readiness to that of others. As a rule, this is said not to be true of those who are in advancing years, but the greater minds among the older men do not get set in their ways. Flourens might have said that because of constant exercise the connective tissue in the brains of such men does not form to the same extent as in others, and does not make them case-hardened. As a consequence, they retain far on in years their sympathy for others' opinions and their openness of mind. Comparatively, they are so few, however, that this expression of Faraday's becomes a striking commentary on his large-mindedness. "For proper self-education, it is necessary that a man examine himself, and that not carelessly either.... A first result of this habit of mind will be an internal conviction of ignorance in many things respecting which his neighbors are taught, and that his opinions and conclusions on such matters ought to be advanced with reservation. A mind so disciplined will be open to correction upon good grounds in all things, even in those it is best acquainted with, and should familiarize itself with the idea of such being the case." Perhaps it is even more interesting, because more humanly sympathetic, to find that Faraday distrusted his opinions of people even more than his opinions of things, and that he himself tried to be very slow to take offence at what was said to him, and counselled greatest discretion to others in judging of the significance of supposed slights. "Let me, as an old man who ought by this time to have profited by experience, say that when I was younger, I found I often misinterpreted the intentions of people, and found that they did not mean what at the time I supposed they meant; and further, that, as a general rule, it was better to be a little dull of apprehension when phrases seemed to imply pique and quick in perception, when, on the contrary, they seemed to imply kindly feeling. The real truth never fails ultimately to appear, and opposing parties, if wrong, are sooner convinced when replied to forbearingly than when overwhelmed."