OSiaiN OF LIFE UPON THE EARTH 189
general growth. There are also catalysers which accelerate or retard the growth of certain organs or parts of the body. The enzyme theory has developed with extreme rapidity but is stilly doubtless^ in its infancy. In the concluding section of this lecture we shall trace these physical and chemical principles into some of the simpler forms of life.^^^
(To he eontiwued)
List of Wobks Gitxd
Abel, John J., 1915. Experimental and Chemical Studies of the Blood with an
Appeal for More Extended Chemical Training for the Biological and Medical
Investigator. Science, August 6, 1915, pp. 165-178.
Bechhold, Heinrich, 1912. Die KoUoide in Biologic und Medizin. Dresden, 1912.
Becker, George F., 1910. The Age of the Earth. Smithsonian Misc. Colls.
Washington, 1910.
^1915. IsoBtasy and Badioactivity. Bull. Geol. Soc. America, March, 1915,
pp. 171-204. Calkins, Oary N., 1916. General Biology of the Protozoan life Cyde. Amer,
Natwralist, May, 1916, pp. 257-270. CampbeU, William Wallace, 1915. The Evolution of the Stars and the Forma- tion of the Earth. Second series of lectures on the William EUery Hale foundation, delivered Dec. 7 and 8, 1914. Fop. 8ci. Mon,, Sept., 1915, pp. 209-235; ScntNTiPio Monthly, Oct., 1915, pp. 1-17; Nov., 1915, pp. 177- 194; Dec., 1915, pp. 238-255. Chamberlin, Thomas Chrowder, 1916. The Evolution of the Earth. Third series of lectures on the William EUery Hale foundation, delivered April 19-21, 1915. BciENnria Monthly, May, 1916, pp. 417-437; June, 1916, pp. 53^-556. Clarke, Frank Wigglesworth, 1873. Evolution and the Spectroscope. Fop. 8oi* Mon^ Jan., 1873, pp. 320-326.
^1916. The Data of Geochemistry. Third edition. Washington, 1916.
Cimiiingham, J. T., 1908. The Heredity of Secondary Sexual Characters in Be- lation to Hormones, a Theory of the Heredity of Somatogenic Characters. Archiv fur Entwichlungsmechanih, Nov. 24, 1907, pp. 372-428. Covier, Baron Greorges L. C. F. D., 1817. Le Bftgne animal distribud d'aprte son Organisation. Tome I., contenant Pintroduction, les mammif^es et lea oiseaux. Paris, 1817.
^1825. Discours sur les revolutions de la surface du globe et sur les change-
mens qu'eUes out produit dans le r^gne animaL See, Becherches sur les Ossemens fossOes. Third edition, Paris, 1825, pp. 1-167. Darwin, Charles, 1859. On the Origin of Species, by Means of Natural Selec- tion; or the Preservation of Favored Baces in the Struggle for life. Lon- don, 1859. Bavies, G. B., 1916. Plato's Philosophy of Education. School and Society,
April 22, 1916, pp. 582-585. Eoeken, Budolf, 1912. Main Currents of Modern Thought. TransL by Booth,
New York, 1912. Halsted, William Stewart, 1915. The Significance of the Thymus Gland in issln addition to the acknowledgments made in the introduction, I especially desire to express my indebtedness to Henry Norris Bussell, of Princeton University, to George EUery Hale, of the Mount Wilson Observatory, to Joseph BarreU and Charles Schuchert, of Yale University, who have kindly cooperated through correspondence and otherwise.
�� �
