Cleanliness of mind and body has been taught for thousands of years, yet cleanliness of body is a new discovery, for which we are greatly indebted to the great bacteriologist, Pasteur. It has been found that germs thrive best in filth; this has been taught so thoroughly that the public is somewhat afraid of the germs and as a measure of self-protection they are cleaning up. Of old, cleanliness meant a clean skin, but this is the least important part. It is far more necessary to have a clean alimentary tract and clean blood, with a resultant sweet, healthy body, and this is what cleanliness is beginning to mean. Internal cleanliness necessitates moderation, for an overworked alimentary tract becomes foul and some of the poisons are taken into the blood. Asepsis and antisepsis simply mean cleanliness. The benefits of moderation have been known for thousands of years. Louis Cornaro, who died in 1566, wrote a delightful book on the subject. People know that it is necessary to be moderate, but they do not seem to realize the meaning of moderation nor is its value well enough implanted in the human mind to produce satisfactory results. Right thinking seemed as important to the thinkers of old as it does to the New Thought people today. "As a man thinketh in his heart, so is he." For the better knowledge of the composition of food we have to thank the chemists. Laymen are referred to frequently in this book because their work has been so helpful and important. Herbert Spencer and Alfred Russel Wallace had very clear conceptions regarding health. See their opinions regarding vaccination. There is no difference in the mental processes of physicians and laymen. Anyone can know about health, though it takes considerable experience and observation to get acquainted with the less important subject of disease. One indictment against medical men is that they have dwelled almost entirely on disease and paid no attention to health. A group of modern men deserve great credit for popularizing health knowledge, which generally results in the loss of professional standing of the teacher. R. H. Trall, M. D., insisted that drugs are useless and harmful, that the only rational and safe way of healing ordinary ills is to use nature's means. "Strictly speaking, fever and food are antagonistic ideas," he wrote. In his Hydropathic Encyclopedia, copyrighted in 1851, he puts great stress on natural remedies, such as food and water. He met with much opposition, but he has left a deep impression on the minds of men who are now having some influence in shaping public opinion on health and healing.