The subject categories are those in A Classified Bibliography of Gerontology and Geriatrics by Nathan W. Shock, published by Stanford University Press, Stanford, California (1951). Only major headings are used and the Roman numerals correspond to those given in the bibliography. Insofar as possible, references are classified according to organ systems. Thus, most of the material on Geriatrics will be found under the organ system involved in the disease. Cross references are indicated by numbers at the end of each section. When available, abstract references are given (B.A.— Biological Abstracts. P.A.—Psychological Abstracts, and P.I.—Population Index). Abbreviations for journals are those in A World List of Scientific Periodicals Published in the years 1900-1933, 2nd Edition. For journals not listed, abbreviations were devised to the general rules used in the above source. It is impossible to cover all journals and list all papers concerned with aging and the aged. Authors and publishers are requested to call attention to publications or to send reprints to the Gerontology Research Center, Baltimore City Hospitals, Baltimore, Maryland 21224.