viii SYNOPTICAL INDEX 



CHAPTER VII. THE LIBERATION OP ENERGY AND EXCRETION 



OF WASTE 



Composition of air, 52 ; relation of organisms to oxygen, 52 ; 

 respiration in animals, 53 ; respiration in plants, 54 ; demonstra- 

 tion of respiration, 56 ; excretion, 57. Circulation of energy, 58. 



CHAPTER VIII. SENSITIVITY IN PLANTS AND ANIMALS 

 Stimuli, 60 ; intensity of stimulus, 60 ; latent period, 61 ; 

 protoplasm the sensitive substance, 61 ; sensitivity in plants, 61 ; 

 nature of the reaction, 62 ; sense organs in animals, 64 ; sense 

 organs in plants, 65 ; importance of sense organs to the animal, 66 ; 

 transmission of stimuli, 68. Orientation of fixed organisms, 69 ; 

 gravity, 69; light, 71 ; water, 72; chemical stimuli, 72 ; oxygen, 

 73. Sensitivity in animals, 74 ; muscle-nerve preparation, 75 ; 

 tetanus, 76 ; central nervous system, 76 ; afferent and efferent 

 nerves, 77 ; reflex action, 77. 



CHAPTER IX. MOTION AND LOCOMOTION. THE SKELETON 

 Motion and locomotion, 78 ; movements of protoplasm, 79 ; 

 organs of locomotion, 80. Skeleton, 80; functions, 80; material-!. 

 82 ; chemical composition, 82 ; structure, 83 ; relative strength 

 of materials, 84 ; arrangement of skeletal materials, 84 ; principle 

 of the girder, 85 ; principle of the hollow column, 86 ; principle 

 of the arch, 88 ; principle of the crane, 90 ; venation of leaves, 91. 



CHAPTER X. THE ADAPTATION OF ORGANISMS TO THEIR 



ENVIRONMENT - 



Nature of the environment, 92 ; mechanical influences, 93 ; 

 chemical influences, 93 ; physical influences, 95 ; vital influences, 

 95. Adaptation of plants to habitat, 96 ; adaptation of organs 

 to special functions, 97 ; experimental work in adaptation, 98 ; 

 mimetic resemblance, 100. 



CHAPTER XL REPRODUCTION 



Antagonism of individual and tribal life, 101 ; asexual reproduc- 

 tion, 101 ; sexual reproduction, 102 ; cell division, 102 ; relation 

 of mass to surface, 103; ovum and sperm, 104. Duration of 

 organisms, 105 ; protection and nourishment of embryos, 106 ; 

 seeds and seed dispersal, 109 ; illustrative examples, 109. 



CHAPTER XII. THE STRUGGLE FOR EXISTENCE AND NATURAL 



SELECTION 



Types of organisms, 112; powers of increase of organisms, 113; 

 destruction of life, 114; struggle for existence, 115; variation and 

 heredity, 116; natural selection, 1J7; mutations, 119. Con- 

 clusion, 119, 



