The object of this book is, primarily, to assist in placing mental therapeutics on a firmly scientific basis, and incidentally to place within the reach of the humblest intellect the most effective methods of healing the sick by mental processes. Part I. contains nothing new to the scientific world, except, perhaps, the method of treatment. It pertains solely to the psychological principles of mental medicine. In Part II. the fact is for the first time recognized that no hypothesis can possibly embrace a complete science of mental therapeutics that fails to take cognizance of those facts of physiology and histology which pertain to the subject-matter.