[Footnote 72: K. Huerthle: Beiträge zur Hämodynamik, Archiv f. d. Ges. Physiologie, vol. 60, p. 281, 1895.] [Footnote 73: Edgren: _loc. cit._ p. 87.] [Footnote 74: A. Chauveau: Inscription électrique des mouvements valvulaires, Journal de Physiologie et de Pathologie Générale, vol. 1, p. 388, fig. 4, 1899.] [Footnote 75: _Ibid._ p. 391, fig. 6 (curve 5); and the same author's La pulsation cardiaque, in the same Journal, vol. 1, p. 795, fig. 5, and p. 796, 1899.] [Footnote 76: Edgren: _loc. cit._ p. 114.] [Footnote 77: The exposition of this theory may be found in R. Tigerstedt: Intracardialer Druck und Herzstoss, Ergebnisse der Physiologie, vol. 1, pp. 258-262, 1902. This theory, equally remarkable for its logical beauty and for its confirmation by Edgren's experiments, has not found its way into recently published text-books of physiology, though Edgren's paper belongs to the most frequently quoted publications on sphygmography and cardiography.] [Footnote 78: Tigerstedt: _loc. cit._ p. 261.] [Footnote 79: Fredericq: La pulsation du cœur chez le chien, no. 5. La comparaison du tracé du choc du cœur avec celui de la pression intraventriculaire, Travaux du Laboratoire de Liège, vol. 5, p. 67, 1896.] [Footnote 80: Galenus: De pulsuum differentiis, lib. 1. c. 16.] [Footnote 81: The amount of change in the base-line is the chief difference between the sphygmograms and the plethysmograms. It was stated recently that for this reason the plethysmograph could not be used for psychological experiments. An analysis of the mechanical conditions of these two instruments shows that also the sphygmogram must show some plethysmographic influences, and the author supplied experimental evidence for this result.] [Footnote 82: More recent publications have taken this view. Cohn speaks of "Organgefühle des Gehirns," approaching Meynert's view on the causes of pleasure and pain. (P. Cohn: Gemüthserregungen und Krankheiten, pp. 23 and 50, 1903.) Cohn's book shows clearly that this theory belongs to the type of philosophical explanations. This is also suggested by Duprat who remarked the parallelism between the theories of James, Lange and Ribot, and the theories of certain Greek philosophers. (Duprat: "La psycho-physiologie des sentiments dans la philosophie ancienne," Archiv f. Geschichte d. Philosophie, vol. 18 (3), p. 395, 1905.)] THE MUTUAL INFLUENCE OF FEELINGS BY JOHN A. H. KEITH The object of this investigation was to ascertain the mutual influence of simultaneous stimuli that appealed to different senses with regard to the _intensity_ of their feeling values. The investigation covers combinations: (1) of colors and active touches, (2) of colors and passive touches, (3) of tones and active touches, (4) of tones and passive touches, (5) of colors and tones. The basis of appreciation was a numerical scale[83] as follows: