THE AMEBIC AN NATURALIST 



[Vol. L 



2. From paleontology, where the history of the phylum 

 seems governed by internal laws. 



3. From experimental breeding where progress is 

 afforded only as internal changes permit. 



4. From analogy, with evolution in the inorganic world, 

 so far as may be inferred from the studies on the "rare 

 earths." 



Such a theory makes clear that success in "selection" 

 depends on rate and amplitude of internal change and 

 ability to judge of germinal from somatic conditions. 



It renders less hopeful (but not hopeless) the prospect 

 of being able to control completely by experimental 

 methods evolutionary change. 



Carnegie Institution of Washington, 



Station for Experimental Evolution, 



Cold Spring Harbor, Long Island, N. Y. 



V. LITERATURE CITED 

 Beecher, C. E. 1898. -The Origin and Significance of Spines. Amer. 



Jour. Sci., VI, 1-20; 125-136; 249-268; 329-359. July-Oct. 

 Bergson, H. 1913. Creative Evolution. Transl. by A. Mitchell. 407 



pp. N. Y. 



Castle, W. E. 1914. Piebald Eats and Selection. Publ. 195. Carnegie 



Inst, of Washington, 56 pp. 3 plates. 

 Castle, W. E. 1915. Some Experiments in Mass Selection. Amer. Nat., 



49: 713-726. Dec. 



Castle, W. E. 1916. Can Selection cause Genetic Change? Amer. Nat., 



50: 248-256. April. 

 deVries, II. 1906. Species and Varieties: Their Origin by Mutation. Ed. 



by D. T. MacDougal. 2d ed. 847 pp. Chicago, Open Court Publ. 



Co. 



Hagedoorn, A. L. Autokatalytieal Substances the Determinants for the 

 Inheritable Characters, a Biochemical Theory of Inheritance and Evo- 

 lution. Vortr. u. Aufs. iiber Entwicklungsmechanik der Organismen, 



Loomis, F. B. 1905. Momentum in Evolution. Amer. Nat., 39 : 839-844. 

 Nov. 



Lotsy, J. P. 1913. Fortsehritte unserer Anschauungen iiber Deszendenz 

 seit Danvin und der jetzige Standpunkt der Frage. Progressus Bei 

 Botanicce, 4: 361-388. 



Lutz, F. E. 1911. Experiments with Drosophila ampelophila Concerning 

 Evolution. Publ. 143. Carnegie Institution of Washington. 



Mivart, St. G. 1871. The Genesis of Species. London and N. Y., Mac- 



