9. BREWSTER, D. Accidental colors. Article in Edinburgh Ency., 1830, 1,

p. 91.

10. BREWSTER, D. Treatise on Optics. 1831. P. 307.

11. BRÜCKE. Untersuchungen über subjective Farben. Poggendorf Annalen, 1851, 84, 418-452.

12. BUFFON. Sur les couleurs accidentelles. Hist. de l'Acad. de Paris, 1743,

147.

13. CATTELL, J. MCK. & FARRAND, L. Physical and Mental Measurements. Psychol. Rev., 1896, 3, 645.

14. CATTELL, J. McK. Perception of Light. In OLIVER & NORRIS: System

of Diseases of the Eye, 1897, 1, 531-533

15. DARWIN, R. W.

New Experiments on the Ocular Spectra of Light and

Colors. Phil. Trans., 1786, 76, 313-348.

16. DE BERGEN. De maculis et faculis à solis aspectu in oculo residuis. 1757.

17. DE GODART. Deuxième Mémoire d'optique, ou recherches sur les couleurs accidentelles. Journal de physique de Rozier, 8, p. 5.

18. DE LA HIRE. Sur les differens accidens de la Vue. Mém. de l'Acad. Royale des Sc., Paris, 1730, 9, 614.

19. EDRIDGE-GREEN, F. W. Color-Blindness and Color Perception. 1891. P. 182.

20. FECHNER. Ueber die subjectiven Nach- und Nebenbilder. Poggendorf Annalen, 1840. 50, 445-470.

20b. FECHNER. Ibid., 210.

21. FICK, A. Die Lehre von der Lichtempfindung. In HERMAN: Handbuch

der Physiologie der Sinnesorgane, 3, p. 222.

22. FRANZ, S. I. After Images. Psychol. Monog. No. 12, 1899.

23. GOETHE. Zur Farbenlehre. Werke. (Cotta Edit. 1833.) 52, Par. 39-46. 24. HALLER. Elementa physiologiae corporis humani. 5, section 4, 480.

25. HARRIS, D. W. A case of vivid after images explained by the Hering

Theory. Brain, 1900, 23, 691-693.

26. HELMOLTZ.

Handbuch der physiologischen Optik. (2 Aufl.) 521-530.

27. HERING, E. Zur Lehre vom Lichtsinne. Wien: 1878. Par. 2.

27b. HERING, E. Ibid. Par. 43.

28. HERING, E. Ueber die von v. Kries wider die Theorie der Gegenfarben erhobenen Einwände. Pflüger's Arch., 1888, 43, 334.

29. HESS, G. Untersuchungen über die nach kurz dauernder Reizung des Sehorgans auftretenden Nachbilder. Pflüger's Arch., 1891, 49, 198. 30. HODGES, S. On some peculiarities connected with Retinal Images. Brain, 1884, 7, 77-82.

31. HODGES, S. After Images. Nineteenth Century, 1883, 14, 622-638. 32. HOMOUTH, P. Beiträge zur Kenntnis der Nachbilderscheinungen. Arch. f.d. Ges. Psychol., 1913, 26, 181-238.

32b. HOMOUTH, P. Ibid., 268.

33. KIRCHER, A. Ars magna Lucis et Umbrae. 1671.

34. KNOCHENHAUER. Ueber Blendungsbilder. Poggendorf Annalen, 1841, 53,

346-356.

35. V. KRIES, J. Die Gesichtsempfindungen und ihre Analyse. 1882. P. 120. • 36. v. KRIES, J. Die Gesichtsempfindungen. In NAGEL: Handbuch der Physiologie des Menschen, 3, 1905, pp. 228-229.

37. KÜLPE, O. Outlines of Psychology. 1895. P. 131, footnote.

38. MALEBRANCHE. Réflexions sur la lumière et les couleurs. Mém. de l'Acad. des. Sc. de Paris, 1699.

39. MCDOUGALL, W. Some new observations in support of Young's theory of Light and Color-Vision. Mind, 1901, N. S. 10.

40. MICHAELIUS. De oculo, seu natura visus, 1645.

41. MILES, G. H. The formation of projected visual images by intermittent retinal stimulation. ..Brit. J. of Psychol., 1915, 8, 110-120.

42. MONGEZ. Lettre sur une dégradation des couleurs. Jour. de physique de Rozier, 6. 481.

43. MÜLLER, J. Elements of Physiology. (Eng. Trans., Baly.) 1842. 2, 1183.

44. NAGEL, W. A. Ueber die Wirkung des Santonins auf den Farbensinn, u. s. w. Zsch. f. Psychol. u. Physiol. der Sinnesorgane, 1902, 27, 271-272. 45. NOLLET. Leçons de physique expérimentale. 5, 509-510. 46. PARSONS, J. H. Introduction to the Study of Color Vision. 1914. Pp. 110-111.

47. PORTA. De refractione optices parte libri novem. 1593.

48. PLATEAU. Ueber das Phänomen der zufälligen Farben. Poggendorf Annalen, 32, 543.

49. PLATEAU. Bibliographie Analytique des principaux Phenomenes subjectifs de la Vision. Mém. de l'Acad. Royale de Belgique, 1878, 42.

50. PORTERFIELD. A Treatise on the Eye. Edinburgh. 1759.

51. PRIEUR, C. A. Considérations sur les couleurs, etc. Ann. de Chimie et de Physique, Sér. 1, 54.

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53. PURKINJE. Beobachtungen und Versuche zur Physiol. der Sinne.

I.

62. SEGUIN. Mém. sur les images accidentelles des objets blancs. Comptes Rendus, 1870, 70, 322-323.

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64. STEVENSON, P. R. Experiments with the Negative Flight of Colors from a White Light. 1914. (Unpublished Master's thesis. University of Cincinnati.)

Instructor's Manual:

65. TITCHENER, E. B.
Experimental Psychology.
Qualitative, 1910. P. 48.
66. VENTURI. Indagine fisica sui colori. Modena. 1801.
67. WASHBURN, M. F. Subjective Color and the after image:

Their

significance for the Theory of Attention. Mind, 1899. N. S. 8, 25. 68. WASHBURN, M. F. The color changes of the white light after image,

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70. YOUNG, T. Lectures on Natural Philosophy. 1807. Lect. 38.

71. ZAHN. Oculus artificialis teledioptricus. 1685.

CUTANEOUS SPACE

BY HAROLD E. BURTT
Ohio State University

The literature on cutaneous space during the past two years comprises a few studies of local signature, an experiment with a temperature esthesiometer, two cutaneous studies with amputates, an investigation of after-images of movement, considerable discussion of illusions especially those of motion and an experiment on the dynamogenic effects of light. Some foreign literature of earlier date which was delayed by the war is included in the present review.

Ruediger (9) discusses theories of tactual local signature especially the "sensory complex" theory versus the " sensory element " theory. His own experiments appear to substantiate the latter. The subject with eyes closed was touched upon the radial forearm, and then localized the spot with eyes open. Pressures of ten grams and one gram were used. According to the "senso sensory complex" theory the stronger stimulus should give more accurate localization. It failed to do so and in fact there was a slight tendency in the reverse direction. Moreover with the stimulus applied over a vein, where the subcutaneous portion of the complex would be uniform, less accurate localization should be found than elsewhere on the arm. The opposite result was obtained with seven of the eight subjects. In a supplementary series pure cold sensations were obtained and these were located as accurately as touch sensations or touch and cold combined. The writer therefore inclines to the "sensory element" theory.

Lufkin (7) disputes Watt's proposed "attribute of order" which, among other things, is based on the fact that "every touch spot can be distinguished from every other." Watt's experiments were performed on the forearm and Lufkin tried a region on the back where localization would be as free as possible from "empiristic motives (images, reflexes)." Preliminary experiments located an area bounded by the scapulae and the seventh and tenth cervical vertebrae where the observer was often unable to tell whether the right or left side of the spine was stimulated. Selected pressure spots in this region were systematically studied. Successive stimulation of two

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spots on opposite sides of the spine yielded thirteen per cent. " same" judgments. There were also some judgments of this sort when the two spots were on the same side. The percentage of such judgments varied inversely with the distance between the points. With the same spot stimulated twice the report same was given only about half the time. The results do not confirm those of Watt on the forearm and the conclusion is that localization is a matter of perception rather than of sensation.

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Turro (11) gives a critical resumé of theories of tactual space. As a result of his own experiments with children he concludes that in order to localize one needs either active movement or the reproduction of ideas of movement. In a study of amputates he found correct localization only when the subject moved the stump.

Katz (3) studied over one hundred cases of one-arm amputation. The usual illusion of the missing member was diminished in size in nearly every case. This is ascribed to loss of peripheral excitation. Normally we have a sort of sensory "tension" built up through experience out of our tactual and kinesthetic sensations from the limb, and the absence of these sensations gives the illusion that the limb is smaller. Experiments upon the side of the stump and a corresponding area of the normal arm yielded lower thresholds for touch and two-point discrimination on the stump. Articles placed on the stump were recognized more readily than on the normal arm. Localization, however, was poorer on the stump with a constant error in the direction of the shoulder. The author considers these phenomena to be due to attention.

Piéron (8) reports a novel study of thermal-spatial discrimination. The esthesiometer deposited two drops of water on the skin, thus giving a thermal stimulus without a pressure stimulus. Twopoint thresholds were determined in this manner while the temperature of the water was varied from 32 degrees below skin temperature to 21 degrees above. At about skin temperature the threshold was much higher than at extremes of temperature. Comparison with an ordinary esthesiometer on the same cutaneous area was equivocal because of the difference in the size of the stimuli. It is obvious from the experiment, however, that there is a thermal-spatial discrimination.

Thalman (10) applied a moving stimulus to the forearm to see if an after-image of movement would ensue. Various stimuli were used-a knotted string, a wide strip of muslin, a belt of corduroy and a belt of corrugated muslin (with transverse strips attached