The primary object of this book is to assist in bringing Psychology within the domain of the exact sciences. It has long been felt by the ablest thinkers of our time that all psychic manifestations of the human intellect, normal or abnormal, whether designated by the name of mesmerism, hypnotism, somnambulism, trance, spiritism, demonology, miracle, mental therapeutics, genius, or insanity, are in some way related ; and consequently, that they are to be referred to some general principle or law, which, once understood, will simplify and correlate the whole subject-matter, and possibly remove it from the domain of the supernatural.
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.