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138 PHILOSOPHICAL PERIODICALS. ZEITSCHRIFT Fttn PSYCHOLOGIE UND PHYSIOLOGIE DER SINNESORGANE. Bd. xxi., Heft 5. G. Heymans. ' Untersuohungen iiber psychische Hemmung.' [Experiments within the three modalities of sight, taste and hearing : attention held upon the inhibited sensation. General re- sult : the inhibitory effects, as measured by the raising of the stimulus limina are (1) proportional to the intensities of the inhibiting stimuli, (2) where the quality of these is different, to the resistances which they themselves offer to inhibition by other stimuli, and (8) inversely propor- tional to their stimulus limina. It follows that the stimulus limen of ordinary laboratory work is an inhibition phenomenon.] L. W. Stern. ' Die Wahrnehmung von Tonveranderungen, II. Tonunterschiede und Tonanderungen : Paralleluntersuchung nach der Methode des Urtheils- ganges.' [Description of apparatus (blown bottle and variator) and method (course of certainty and accuracy of judgments). Continuous tonal change is easier remarked than corresponding tone difference (dis- crete change) ; the former is grasped in a single act of perception. The interval of 6 seconds proves to be an optimal tune for the perception of tonal change and difference. The reason is to be looked for in the culmination at this point of the second observation-stage (' psychical present') of the individual experiment.] S. Exner. ' Notiz iiber die Nachbilder vorgetauschter Bewegungen.' [Illusory visual movements leave after-images.] Literaturbericht. Bd. xxi., Heft 6. A. Pick. ' Psychiatrische Beitriige zur Psychologic des Rhythmus und Reimes.' [Groos divides hear-plays into productive and receptive. He finds analogues of the former in psychopathology ; the present paper givea instances of receptive rhymes and rhythms in pathological cases. Heart- beat, the movements of walking, etc., play a part beside entotic noises. In general, attentive expectation (Meumann) is of great importance; noticeable also is the involuntariness of the rhythms (</. memory- experiments with nonsense syllables).] Roddingius. ' Die Fixation.' [There is no true 'fixation,' for there can be no sense-stimulus to it; what happens is an alternation of loss and regaining of adjustment, the movements being so slight as to be imperceptible. Discussion of the hypothesis in five cases. (1) Absence of the innervation of conver- gence and divergence : pendular movement of the fovea to the image- point and back again. (2) Binocular vision with orthophoria : homo- geneous innervation of fixation (equality of convergence and divergence stimuli) ; equal movements of the fovese to either side of the image- point. (3) Normal monocular vision : the motor equivalent of the dis- persion circles is an impulse put together of equally intensive stimuli from accommodation, pupil convergence and divergence. (4) Binocular vision : esophoria, enhancement of the impulse to divergence ; exophoria, diminution of it. (5) Binocular vision with hyperphoria : necessary to assume a paired vertical innervation vertical convergence and diver- gence.] R. Simon. ' Ueber die Wahrnehmung von Helligkeitsunter- schieden.' [Influence of practice ; of the magnitude of the illuminated field of vision ; of the visual angle ; of monocular and binocular experi- mentation ; of the method of investigation. Weber's law holds only ap- proximately ; or at least, if valid, is valid only over a certain limited range of intensities.] Literaturbericht. L. W. Stern. 'Erklarung.' [Reply to Meyer.] Bd. xxii., Heft 1. L. W. Stern. ' Die Wahrneh- mung von Tonveranderungen, in. Die Wahrnehmung von Tonverander- ungen sehr verschiedener Geschwindigkeit.' [The limen of change, contrary to the accepted opinion, falls with decrease of rapidity of change. An explanation is sought in the law of optimal times. Reply to Stratton's criticisms.] L. W. Stern. ' Ein Beitrag 7,ur differentiellen Psychologic des Urtheileus.' [A contribution to the 'individual' psy-