normal variability in the function of dark-adaptation and the refractory period, such variation being probably due to changing physiological conditions. The dilatation of the pupils by atropin and homatropin seems to have little or no effect upon dark-adaptation except to make it a little more prolonged. This prolongation is due to the over-stimulation of the retina by light caused by a toolong sustained dilated pupil. It also seems safe to infer that the iris plays a minor part, if any, in the visual phenomenon which resembles refractory phase. Because of the limited number of cases involved the conclusions drawn from this study must be taken as suggestive and not as final evidence. MADISON BENTLEY, UNIVERSITY OF ILLINOIS HOWARD C. WARREN, PRINCETON UNIVERSITY (Review) JOHN B. WATSON, NEW YORK CITY (Review) SHEPHERD I. FRANZ, UNIV. OF CALIF., So. BR. (Monographs) S. W. FERNBERGER, UNIVERSITY OF Pennsylvania (Bulletin) EDITED BY HOWARD C. WARREN, PRINCETON UNIVERSITY (Review) JOHN B. WATSON, 244 MADISON AVE., NEW YORK (Review) SHEPHERD I. FRANZ, UNIV. OF CALIF., So. BR. (Monographs) MADISON BENTLEY, UNIVERSITY OF ILLINOIS (J. of Exp. Psych.) S. W. FERNBERGER, UNIVERSITY OF PENNSYLVANIA (Bulletin) WALTER S. HUNTER, CLARK UNIVERSITY (Index) WITH THE CO-OPERATION OF MANY DISTINGUISHED PSYCHOLOGISTS PSYCHOLOGICAL REVIEW containing original contributions only, appears bimonthly, January, March, May, July, September, and November, the six numbers comprising a volume of about 480 pages. PSYCHOLOGICAL BULLETIN containing abstracts, critical reviews of books and articles, psychological news and notes, university notices, and announcements, appears monthly, the annual volume comprising about 720 pages. Special issues of the BULLETIN consist of general reviews of recent work in some department of psychology. JOURNAL OF EXPERIMENTAL PSYCHOLOGY containing original contributions of an experimental character, appears bimonthly, February, April, June, August, October, and December, the six numbers comprising a volume of about 480 pages. PSYCHOLOGICAL INDEX is a compendious bibliography of books, monographs, and articles upon psychological and cognate topics that have appeared during the year. The INDEX is issued annually in May, and may be subscribed for in connection with the periodicals above, or purchased separately. PSYCHOLOGICAL MONOGRAPHS consist of longer researches or treatises or collections of laboratory studies which it is important to publish promptly and as units. The price of single numbers varies according to their size. The MONOGRAPHS appear at irregular intervals and are gathered into volumes of about 500 pages. Philosophical Monographs: a series of treatises more philosophical in character. Library of Genetic Science and Philosophy: a series of bound volumes. ANNUAL SUBSCRIPTION RATES Review: $5.00 (Foreign, $5.25). Review and Bulletin: $9.50 (Foreign, $10.00) Journal: $5.00 (Foreign, $5.25). Review and Journal: $9.00 (Foreign, $9.50) Bulletin: $5.50 (Foreign, $5.75). Journal and Bulletin: $9.50 (Foreign, $10.00) Any one of above with Index: $1.50 additional. Review, Bulletin, and Journal: $14.00 (Foreign, $14.75). Review, Bulletin, Journal, and Index: $15.00 (Foreign, $15.75). Current Numbers: Review or Journal, $1.00; Bulletin, 6oc: Index, $2.00 Current Issues: prices vary according to size. Subscriptions, orders, and business communications may be sent direct to the PRINCETON, N. J. OFFICE PSYCHOLOGICAL REVIEW COMPANY FOREIGN AGENTS: G. E. STECHERT & CO., London (2 Star Yard, Cary St., W.C.), Paris (16, rue de Condé) EXP It has been found that work done under the guidance of the eyes is facilitated, in some cases, by an increase in the amount of light. Investigations which have shown this are of two types. First, tests in factories under actual working conditions show an increased output of work under a higher intensity of illumination (1). Secondly, in the laboratory the same problem has been attacked in an analytical way. The threshold-time of exposure of a test-object has been found, in general, to be shorter with the higher illumination (2, 3). Beyond, say, 0.3 sec. the time of exposure is hardly critical. Under ordinary working illuminations, what is not seen within that time would seldom, if ever, be seen. The threshold exposure-time has been found to vary from about this value to a very few thousandths of a second, depending upon the conditions. This is one datum in the problem. With the knowledge of the least time that an image must be allowed to act upon the retina to determine an appropriate response, the question at once arises: In the ordinary use of the eyes, what is the least time that the image is, in fact, allowed to act? The eyes are continually in motion, and their movement has been shown to consist mainly of rapid sweeps, long or short, with brief pauses. During the sweeps it is obviously 359 |