xxiv CONTENTS 



PAGE 



New organic compounds 60 



Interactions — enzymes, antibodies, hormones, and chalones . 71 



Chemical messengers 72 



Physicochemical differentiation 78 



CHAPTER III 



Energy Evolution of Bacteria, Alg^, and Plants 



Evolution of bacteria 80 



Protoplasm and heredity-chromatin 91 



Chlorophyll — the sunlight converter of plants .... 99 



Evolution of ALGiE^THE most primitive plants loi 



Plant and animal evolution contrasted 105 



PART 11. THE EVOLUTION OF ANIMAL FORM 



CHAPTER IV 



The Origins of Animal Life and Evolution of the 

 Invertebrates 



Evolution of Protozoa no 



Evolution of Metazoa 117 



Cambrian invertebrates 118 



Environmental changes 134 



Mutations of Waagen 138 



CHAPTER V 



Visible and Invisible Evolution of the Vertebrates 



Evolution of the germ 141 



Character evolution 146 



The laws of adaptation 152 



