A long time has elapsed since the second edition of this book was sold out.  The present edition is, in reality, a new book instead of what is ordinarily understood as a revision.  The material which was developed for the first and second editions was entirely destroyed by the dynamite explosion and fire which wrecked the great estab-lishment of the Los Angeles Times and killed more than a score of its employees.

    The demand for this book having grown steadily more insistent and the more important fact that, during the time since the publication of the second edition, there has been a great development in every phase of osteopathic teaching and practice, has led us to attempt to produce an edition of Principles of Osteopathy which will be even more useful to students and practitioners than our former editions.

    The experimental work done in the laboratories of our colleges and of private investigators, as well as the recorded experiences of our practitioners, tend more and more to substantiate the Principles of Osteopathy as set forth in our previous editions.  The feeling that this book will furnish genuine assistance in the teaching and practice of osteopathy leads the author to send it forth, with the belief that its imperfections will be kindly excused by its readers, in view of the spirit of generous helpfulness toward all schools of medicine which has been made the reason for its existence.

    Nearly every chapter is in some degree changed or completely rewritten.  Several new chapters, of practical value, have been added.  Much of the material in early chapters of the former editions, relating to histology, has been eliminated.

    The writer wishes to express his gratitude to John Comstock for his valuable assistance in illustrating this edition.