440 PHILOSOPHICAL PERIODICALS. points out that use was never made of it by Aristotle or by the better known scholastics. ZEITSCHRIFI' FUR PSYCHOLOGIE UND PHYSIOLOGIE DER SINNESORGANE. Bd. xii., Heft 2. J. von Kries. ' Ueber die Wirkung kurzdauernder Lichtreize auf das Sehorgan.' [New experiments on recurrent vision. Failure of the phenomenon at the fixation point : its dependence upon adaptation. Comparison with the 'flickering heart' (Szili, etc.). Tenta- tive explanation, in terms of the author's theory of vision.] R. Simon. ' Zur Lehre von der Entstehung der koordinierten Augenbewegungen.' [Empirism and nativism : Helmholtz v. Hering. Bonders' proposal of crucial experiments on animals has never been taken up. Better are human cases of connate muscular anomaly, where binocular vision persists: e.g., paralysis of the abducens or insufficiency of the superior and inferior recti and obliqui. Both tell for Helmholtz.] E. Roemer. ' Zur Frage der psychischen Zeitmessungen bei Geisteskranken.' [For Kraepelin, against Ziehen.] Litteraturbericht. Bd. xii., Heft 3 und 4. E. Koettgen imd G-. Abelsdorff. ' Absorption und Zersetzung des Sehpurpurs bei den Wirbeltieren.' [The maximum of absorption for mammals (including man), birds and amphibia lies at about the wave-length 500, for fish at about 540/n/i. No evidence of visual yellow in animals.] S. Witasek. ' Ueber willkuerliche Vorstel- lungsverbindung.' [The two kinds of centrally aroused ideas : repro- ductive (" anschaulich ") and surrogate (" unanschauh'ch "). Passage from latter to former is either direct, by way of consolidated contents, or indirect, part after part of the reproduction coming up. It involves an idea of relation. It depends on two factors : the proportion of directly to indirectly ideated attributes in the surrogate idea, the "Leistungs- f aehigkeit ' ' of that idea ; and the disposition to the formation of the reproduction, the degree of practice. The two factors form inversely related continua. Characteristic of these connexions in general is a volition, whose object, an idea, is thought bj r the aid of a relation and another idea, which constitutes one term of this relation ; the second idea must be different in contents from the idea willed, but have the same object ; this condition affords a general determination of the rela- tion. The four possible cases : reproduction to reproduction, reproduc- tion to surrogate, etc. Relation to current views : Wundt, the associa- tionists. (The article follows from Meinong's work on imagination, and uses Meinong's terminology.)] J. Merkel. ' Die Abhaengigkeit zwis- chen Reiz und Empfindvmg.' [Defence of the author's position against Meinong's attack.] G-uillery. ' Vergleichende Untersuchungen ueber Raum-, Licht-, und Farbensinn in Centrum und Peripherie der Netzhaut.' [The magnitude of the physiological point (black on white), the magni- tude of the surface necessary for the perception of a determinate bright- ness-difference, and the magnitude of that required for a determinate colour perception are ascertained at centre and periphery (four chief meridians) of the retina. The results, all reduced to terms of the physio- logical point, give an idea of the distribution of the various sensitive elements concerned over the retinal area.] T. lapps. ' Berichtigung.' [To the author's paper on geometrical optical illusions.] Litteratur- bericht. [Ziehen on Wundt's Grundriss.] Bd. xii., Heft 5 und 6. S. Exner. ' Ueber autokinetische Empfin- dungen.' [If a point of light is fixated in an otherwise dark room, it appears to move. Our judgment of the direction of our line of vision is in any case very uncertain. The retinal local sign helps us, if several points are in the field at the same time. But the single point lias a
