The general chapters are particularly helpful. MORGAN, T. H. 1907. Experimental Zoölogy, pp. 454. New York. Summaries of a variety of experimental studies. SEMPER, K. 1881. Animal Life as Affected by the Natural Conditions of Existence. pp. 472. New York. “‘The Physiology of _Organisms_,’ in contradistinction to the Physiology of _Organs_, ... [is] that branch of animal biology which regards the species of animals as actualities and investigates the reciprocal relations which adjust the balance between the existence of any species and the natural, external conditions of its existence, in the widest sense of the term.” p. 33. JENSEN, P. 1907. Organische Zweckmässigkeit, Entwicklung und Vererbung vom Standpunkt der Physiologie. Jena. pp. 251. VERNON, H. M. 1903. Variation in Animals and Plants. pp. 415. London. VARIGNY, H. DE. 1892. Experimental Evolution, pp. 271. New York. BACHMETJEW, P. 1901-1907. Experimentelle entomologische Studien vom physikalisch-chemischen Standpunkt aus. Bd. I. Temperaturverhältnisse bei Insekten. pp. 160. Leipzig. 1901. Bd. II. Einfluss der Ausseren Faktoren auf Insekten. pp. 944. Sophia. 1907. An extremely valuable index to environmental influences upon insects. Numerous summaries. HERRICK, C. L. 1906. Applications of Dynamic Theory to Physiological Problems. Jour. Comp. Neurol. and Psychol., Vol. XVI, pp. 362-375. RICHARDS, H. M. 1910. On the Nature of Response to Chemical Stimulation. Science, N. S., Vol. XXXI, pp. 52-62. SCHÄFER, E. A. 1912. The Nature, Origin and Maintenance of Life. Science, N. S., Vol. XXXVI, pp. 289-312. BASKERVILLE, C. 1905. Life and Chemistry. Science, N. S., Vol. XXI, pp. 641-648. MORGAN, T. H. 1910. Chance or Purpose in the Origin and Evolution of Adaptation. Science, N. S., Vol. XXXI, pp. 201-210. MATHEWS, A. P. 1905. A Theory of the Nature of Protoplasmic Respiration and Growth. Biol. Bull., Vol. VIII, pp. 331-346. JENNINGS, H. S. 1912. Age, Death and Conjugation in the Light of Work on Lower Organisms. Pop. Sci. Mo., Vol. LXXX, pp. 563-577. Death is due to differentiation and not to a “running down” of the organism. LILLIE, F. R. 1909. The Theory of Individual Development. Pop. Sci. Mo., Vol. LXXV, pp. 239-252. HOLMES, S. J. 1904. The Problem of Form Regulation. Archiv für Entwickelungsmechanik der Organismen (Roux), Bd. XVII, pp. 265-305. 1907. Regeneration as Functional Adjustment. Jour. Exp. Zoöl., Vol. IV, pp. 419-430. WILSON, E. B. 1905. The Problem of Development. Science, N. S., Vol. XXI, pp. 281-294. SHERRINGTON, C. S. 1906. The Integrative Action of the Nervous System. pp. 411. New York. The activity of the nervous system is viewed as a _regulatory process_.