xii TABLE OF CONTENTS 
CHAPTER XVIII. OTHER THEORIES OF SPECIES-FORMING 
Theories Auxiliary to Natural Selection 
Weismann’s Theory of Panmixia . 
Weismann’s Theory of Germinal Selection , : : 
Roux’s Theory of Intraselection or the Battle of the Parts 
Coincident Selection or Organic Selection 
Isolation Theories . : 
Theories Alternative to Natural Selection. oe ae SP oe 
CHAPTER XIX. A New Composite Causo-MECHANICAL THEORY 
oF EVOLUTION (THE TETRAKINETIC THEORY). Henry Fairfield 
Osborn Yet cdl ats «ee es 
The Energy Concept st Life, 
The Four Complexes of Energy . 
PART IV. GENETICS 
CHAPTER XX. THE SCOPE AND METHODS OF GENETICS . 
Definitions . 
The Scope and Mietliods of Genetics i 
The Importance of the Cell Theory in Genetics ‘ F 
_ CHAPTER XXI. Tue BEARERS OF THE HERITAGE (an aarti of the 
Cellular Basis of Heredity). Michael F. Guyer 
_CuapTeR XXII. Variation. Ernest Brown Babcock and ‘Roy 
Elwood Clausen 
CHAPTER XXIII. ARE ACQUIRED Gicenedee ee 
: HEREDITARY? . fu 
oe as to the Guestion: at Tesie: F "Arthur Thom- 
son 
The Takavbancs. or “Non-Tiihetitande of Kenvired Characters. 
Edwin Grant Conklin . 
The Other Side to the Question . 
A Possible Mechanism for the "Tranismiigetori of Acquired Characters. 
Michael F. Guyer ‘ 
CHAPTER XXIV. THE eee TunoRy 
New Species (Mutants) of Oenothera. Hugo De Vries 
Summary of De Vries’s Mutation Theory. Thomas Hunt M ilies 
Criticisms . ‘ ft cid otal, oh, Oxley Jad Sy 
Causes of Mutations: : ; in 4 Boge cB 
CHAPTER XXV. BrIoMETRY (THE Sens er OF Wachee 
AND Herepity). H.H.N 
The Statistical Study of Variation . 
Bimodal and Multimodal Curves 
The Coefficient of Correlation bs eat sas Ce 
Statistical Study of Inheritance. Edwin Grant Conklin 
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