THE JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION

THE PHYSIOLOGY AND PATHOLOGY OF THE PINEAL BODY  Of all the "ductless glands" the pineal body has disclosed the least concerning its reason for existence, not enough having yet been learned by the physiologists to afford a basis for even a working hypothesis. Because of its inaccessible location experimental investigation in the living animal has been unsatisfactory or impossible, and practically nothing has been learned by experimental feeding or by injection of extracts. While clinical and pathologic observations have added much to our knowledge concerning the functions of other organs of this class, these sources of information have not been of service in the problem of the pineal gland, for the simple reason that pathologic changes are almost unknown in this organ. About the only lesions described, except for a few instances of tubercle and gumma, are tumors, and in a review of the literature Pappenheimer¹ was able to collect