A4 TABLE OF CONTENTS PAGB A MILLION DOLLARS A DAY FOR LIGHT. By C. E. Clewell, E.E... 61 O THE SOCIAL VALUES OF HISTORY. By Albert E. McKinley, Ph.D.. 73 ○ THE CONSERvation of HorSES IN WAR. By Clarence J. Marshall, THE BASILICA OF ST. PETER IN ROME. By Prof. Alfred H. Gumaer 147 6 ADVERTISING: A DETERMINING FORCE IN OUR NEW BUSINESS RELA- THE FAMILIAR ESSAY. By Percy Van Dyke Shelly, Ph.D.......... 227 THIS GENERATION AND THE NEXT IN RELATION TO MENTAL DEFECT. By Charles H. Frazier, M.D., Sc.D. Changes in College Entrance Requirements during the Last HUNDRED YEARS. By George G. Chambers, Ph.D.. 0 SOCIAL SERVICE PROBLEMS IN EUROPE.. By Daniel J. McCarthy, 353 PRACTICAL USES OF THE X-RAY. By Henry K, Pancoast, M.D.......... 399 PREFACE The Public Lecture Course, consisting of lectures delivered every Saturday afternoon during the year by members of the various faculties of the University of Pennsylvania, continues to attract large. and interesting audiences. The secret of this seems to be that these lectures contain the best thought of men who for years have been pursuing special lines of investigation. It is with pleasure, therefore, that this volume, which is the fourth in the series, is presented to the reading public. It may be added that the early appearance of this volume is due to the kind and generous support of Henry Reed Hatfield, Esq., of the Class of 1878 College. It is another evidence of his devotion to the educational work of his Alma Mater. |