CONTENTS. 



Page. 



CHAPTER I. 



INTRODUCTION... ... ... ... ... ... 1 



CHAPTER II. 



FOUNDATIONS OF THE MUTATION CONCEPT ... 6 



DUPLICATE FACTOR MUTATIONS 12 



RECESSIVE MENDELIAN FACTOR MUTATIONS ... 15 



MUTATIONS ARISING AT OR AFTER FERTILIZATION 17 



MUTATIONS IN DROSOPHILA 20 



CHAPTER III. 



FORMS HAVING AN EXTRA CHROMOSOME ... 24 



CHAPTER IV. 



NON-DISJUNCTION IN DROSOPHILA 35 



CHAPTER V. 



PARALLEL MUTATIONS 43 



THE CRUCIATE CHARACTER 48 



PARALLEL MUTATIONS IN DROSOPHILA 52 



CHAPTER VI. 



PRESUMPTIVE MUTATIONS IN WILD AND CULTI- 

 VATED PLANTS 55 



DOUBLING ... ... ... 56 



PELORIA ... ... ... ... ... ... 64 



OTHER MUTATIONS IN WILD AND CULTIVATED 

 PLANTS 66 



CHAPTER VII. 



MUTATIONS IN ANIMALS 72 



CHAPTER VIII. 



LIMITATIONS OF THE CELL THEORY 76 



CHAPTER IX. 



THE RECAPITULATION THEORY 81 



RECAPITULATION PHENOMENA IN GAMETOPHYTES 83 



RECAPITULATION IN THE SPOROPHYTE 86 



RECAPITULATION IN ANIMALS ... ... ... 88 



CHAPTER X. 



INHERITANCE OF ACQUIRED CHARACTERS ... 94 



CHAPTER XI. 



GENERAL COMPARISON OF RECAPITULATORY AND 



KARYOGENETIC CHARACTERS 99 



THE BIOGENETIC LAW ... 99 



RELATION TO GEOGRAPHIC DISTRIBUTION ... 100 

 THE NEO-LAMARCKIAN PRINCIPLE 101 



CHAPTER XII. 



ORTHOGENETIC CHARACTERS 103 



LITERATURE CITED 105 



INDEX 113 



