“Heresy” until a very short time ago was regarded as a disease. Nowadays when we see a man neglecting the personal cleanliness of his body and his home and exposing himself and his children to the dangers of typhoid fever or another preventable disease, we send for the board-of-health and the health officer calls upon the police to aid him in removing this person who is a danger to the safety of the entire community. In the sixteenth and seventeenth centuries, a heretic, a man or a woman who openly doubted the fundamental principles upon which his Protestant or Catholic religion had been founded, was considered a more terrible menace than a typhoid carrier. Typhoid fever might (very likely would) destroy the body. But heresy, according to them, would positively destroy the immortal soul. It was therefore the duty of all good and logical citizens to warn the police against the enemies of the established order of things and those who failed to do so were as culpable as a modern man who does not telephone to the nearest doctor when he discovers that his fellow-tenants are suffering from cholera or small-pox. In the years to come you will hear a great deal about preventive medicine. Preventive medicine simply means that our doctors do not wait until their patients are sick, then step forward and cure them. On the contrary, they study the patient and the conditions under which he lives when he (the patient) is perfectly well and they remove every possible cause of illness by cleaning up rubbish, by teaching him what to eat and what to avoid, and by giving him a few simple ideas of personal hygiene. They go even further than that, and these good doctors enter the schools and teach the children how to use tooth-brushes and how to avoid catching colds. The sixteenth century which regarded (as I have tried to show you) bodily illness as much less important than sickness which threatened the soul, organised a system of spiritual preventive medicine. As soon as a child was old enough to spell his first words, he was educated in the true (and the “only true”) principles of the Faith. Indirectly this proved to be a good thing for the general progress of the people of Europe. The Protestant lands were soon dotted with schools. They used a great deal of very valuable time to explain the Catechism, but they gave instruction in other things besides theology. They encouraged reading and they were responsible for the great prosperity of the printing trade.