Wallace Delois Wattles 
The science of being well 

Health is the result of thinking and acting in a Certain Way; and if a sick manbegins to think and act in this Way, the Principle of Health within him will come into constructive activity and heal all his diseases. This Principle of Health is the same in all, and is related to the Life Principle of the universe; it is able to heal every disease, and will come into activity whenever man thinks and acts in accordance with the Science of Being Well. Therefore, every man can attain to perfect health