XIV TABLE OF CONTENTS 



PAGE 



Chapter XVIII. Critique of Darwinism 254 



Summary of Darwin's Natural-Selection Theory. Vernon L. Kellogg 254 



Objections to Darwinism 256 



Defense of Darwinism 261 



General Defense of Darwinism. J. L. Tayler 262 



Experimental Support of the Effectiveness of Natural Selection . . 265 



The Present Status of Natural Selection . 267 



The Relation of Mendelism and the Mutation Theory to Natural 



Selection. C. C. Nutting 267 



Chapter XIX. Other Theories of Species-Forming . . . . 272 



Theories Auxiliary to Natural Selection 272 



Weismann's Theory of Panmixia 272 



Weismann's Theory of Germinal Selection 274 



Roux's Theory of Intraselection or the Battle of the Parts . . 277 



Coincident Selection or Organic Selection 277 



Isolation Theories 278 



Theories Alternative to Natural Selection 282 



Chapter XX. A New Composite Causo-mechanical Theory of 



Evolution (the Tetrakinetic Theory). Henry Fairfield Osborn 284 



The Energy Concept of Life ■ 284 



The Four Complexes of Energy 289 



PART IV. GENETICS 



Chapter XXI. The Scope and Methods of Genetics .... 295 



(/ Definitions 295 



The Scope and Methods of Genetics . 295 



Heredity, Environment, and Training 297 



Chapter XXII. How Organisms Reproduce Themselves . . . 299 



V Reproductive Processes 299 



Sexual or Gametic Reproduction 301 



Chapter XXIII. The Bearers of the Heritage: An Account of 



the Cellular Basis of Heredity. Michael F. Guyer . . . 303 



Chapter XXIV. Variation and Heredity .320 



Introductory Statement 320 



Chapter XXV. Variation. E. B. Babcock and R. E. Clausen '. . 323 



Chapter XXVI. Mendel's Laws of Heredity 339 



Mendel's Life and Character. J . A. Thomson 339 



Mendel's Discoveries. /. A. Thomson 339 



Mendel's Explanations. John M. and Merle C. Coulter .... 345 



Illustrations of Mendelian Inheritance. /. A. Thomson .... 352 



