The subjects herewith presented, while including certain of the most important sections of mental disease, make no claim to completeness either in the subject matter presented or in the attempt to cover the entire field of the psychoses. They cover those portions, however, with which we have come in closest touch at the Still-Hildreth Sanatorium, and in which we have the most complete records. I have been aided in the compilation of the essential facts and statistics by the able staff of the institution and wish to acknowledge especially the valuable cooperation of Dr. C. M. VanDuzer in the Dementia Praecox group, Dr. H. P. Hoyle in the Manic Depressive group, Dr. B. L. Jemmette in the group entitled Delirium, Confusion and Stupor, Dr. J. C. Snyder in the Senile Dementia group and Dr. G. S. Elkins in the Involutional group. The opinions concerning each type held by Dr. A. G. Hildreth are appended under its appropriate heading. I wish to state emphatically that the sole treatment carried out in the Macon Institution is specific corrective work upon spinal lesions, and it is upon this treatment that the statistics are based which are to be found throughout the text. These records cover more than 700 cases, including complete histories of the patients with the physical and mental findings on examination; these represent, therefore, by far the largest body of statistics ever accumulated in the study of osteopathic results in mental disorders. While the results naturally vary in different types of mental disease the grand total shows that more than one-half of all patients admitted recovered. Details for each group will be mentioned under its appropriate heading. While adjuncts such as diet and hydrotherapy have been utilized; we certainly cannot attribute any curative value to their influence. It should be further emphasized that in no case whatsoever has medicine been used as a curative agent. And the same may be said of surgery. It has indeed been conclusively proved even in the medical world that medicines and surgical procedures are absolutely ineffective; from the osteopathic viewpoint this of course is perfectly reasonable since the theory calls for definite lesions as causative factors and these lesions can hardly be reached other than by the osteopathic method of correction. The results obtained, therefore, could only be attributed to the genuine osteopathic principle enunciated by Dr. A. T. Still who kept in close touch with the work and gave it his approval up to the time of his death. He had always maintained that the osteopathic principle could accomplish remarkable results in this field and considering the previous inefficiency of any other method his confidence has been fully justified. Dementia Praecox