CONTENTS vii 



PAGES 



CHAPTER IV. THEORIES OF HEREDITY - 50-80 



I. THEORIES OF REPRODUCTION AND REGENERATION 50 



(a) SPENCER'S PHYSIOLOGICAL UNITS - 51 



(b) DARWIN'S PANGENESIS - - 54 



(c) GALTON'S STIRP THEORY - 55 



(d) WEISMANN'S GERM-PLASM - 57 



II. THEORY OF MATURATION - 64 



III. THEORY OF FERTILIZATION - 68 



A. MIXING OF PARENTAL QUALITIES - 69 



(a) BLENDED INHERITANCE - 70 



(b) EXCLUSIVE INHERITANCE - - 72 



(c) PARTICULATE INHERITANCE - 73 



(d) INDIVIDUAL TRAITS - 74 



B. QUANTITATIVE CONTRIBUTION OF ANCESTORS - 75 

 IV. THEORIES OF DEVELOPMENT - 77 



(a) EVOLUTION V. EPIGENESIS - 77 



(b) GERMINAL SELECTION - "79 



CHAPTER V. THEORIES OF HEREDITY (Continued] 81-92 



I. REVERSION- - 8 1 



(a) TO GRANDPARENTS - 8 1 



(b) TO DISTANT ANCESTORS - 84 

 II. TELEGONY - 86 



III. XENIA - 87 



IV. MATERNAL IMPRESSIONS - - 88 



V. DETERMINATION OF SEX - - 89 



(a) INFLUENCES OF FOOD AND OTHER AGENCIES - 90 



(b) INFLUENCE OF PARENTS - 90 



(c) INTERNAL CONDITIONS OF THE GERM - 91 



CHAPTER VI. THE INHERITANCE OF ACQUIRED 



CHARACTERS 93-107 



I. THEORETICAL CONSIDERATIONS - - 93 



II. THE FACTS AND THEIR INTERPRETATION - - 95 



(a) INHERITANCE IN UNICELLULAR ORGANISMS - 96 



(b) MUTILATIONS - ~ 97 



(c) CONGENITAL TRAITS - 98 



(d) GERMINAL VARIATIONS - - 99 



(e) ACQUIREMENTS - - IOI 

 (/) ENVIRONMENTAL INFLUENCES ON GERM-CELLS- IO3 

 (g) EXTERNAL OR SOCIAL INHERITANCE - - 104 



III. CONFUSION OF THE ISSUES - 105 



(a) EVOLUTION AND DEVELOPMENT - 105 



(b) LAMARCKISM V. NATURAL SELECTION - - IO6 



