xii CONTENTS 



CHAPTER III 

 Multicellular Organisms and Division op Labor 



PAGE 



Nature of the Subject 24 



Amoeba 25 



Paramocoium 26 



'Iin|)ortanc-e of One-Celled Organisms 27 



Colonial Forms 27 



Volvox 28 



Hydra 29 



Division of Labor 30 



Tissues, Organs and Systems 32 



Section 2. The Role of Green Plants 



CHAPTER IV 

 The Manufacture of Foods and Fuels 



The Annual Value of Food 37 



Annual i'roduction of Food Necessary 37 



The Food Materials 37 



Water and Mineral Salts 38 



The Composition of Food Materials 38 



The Absorption of Foo<l Materials 38 



Tlie Working Over of Food Materials 38 



Riidiant Energy 39 



Photosynthesis 39 



('hlorophyll 40 



Orcurrenre of Chlorophyll 40 



What Limits Photosynthesis 41 



The Photochemical Reactions in Photosynthesis 42 



Von Bayer's Hypothesis of Photosynthesis 43 



The Products of Photosynthesis 43 



CHAPTER V 

 The Building of the Living Machine 



The Living Machine 45 



The Com|>osition of Protoplasm 45 



Nitrogen 45 



Physical Properties of Proteins 46 



The Amino- Acids 46 



The Synthesis of Proteins from Amino- Acids 47 



The Organization of Protoplasm 48 



The Fvjnrtioning (»f Pr(»toplasm 49 



The (Irowth of Protoplasm 49 



The Death of Protoplasm 49 



The Mineral Constituents 50 



Potassium 50 



Iron 51 



