LIST OF ILLUSTRATIONS 



FIGURE PAGB 



1. Protective Coloration of the Rocky Mountain White-tailed 



Ptarmigan 29 



2. The Sussex Man 34 



3. Positive Heliotropism of a Marine Worm .... 47 



4. Comparison of the Embryos of Man and Other Vertebrates 50 



5. Venus' Fly-trap 53 



6. Contest between Ant-bear and Puma 76 



7. Horror and Agony 124 



8. Athlete making a Record Broad Jump 126 



9. Finish of One-half Mile Intercollegiate Race . . . 127 



10. Athlete breaking the Record for Shot Put . . . .128 



11. Anger in Male Gorilla 129 



12. Exhausted Suffragist 130 



13. Cat Terrified by Dog 131 



14. Violent Effort ..133 



15. Exhaustion 134 



16. Tigress and Cubs at Rest . 135 



17. Composure 137 



18. Photomicrographs showing Effects of Acute and of Chronic 



Fright on the Brain-cells of a Rabbit .... 139 



19. Case of Exophthalmic Goiter 142 



20. Tracing showing Effect of Fear on Adrenal Output of a 



Cat 146 



21. Photomicrographs showing the Effect of Fright on the 



Brain-cells of a Rabbit 149 



22. Photomicrographs showing the Effect of Fright on the Ad- 



renals of a Rabbit 150 



23. Photomicrographs showing the Effect of Fright on the Liver 



of a Rabbit 151 



24. Photomicrographs showing the Effect of Insomnia on the 



Brain-cells of a Rabbit 166 



25. Photomicrographs showing the Effect of Insomnia on the 



Adrenals of a Rabbit 167 



26. Photomicrographs showing the Effect of Insomnia on the 



Liver of a Rabbit 168 



27. Photomicrographs showing the Effect of Exertion on the 



Brain-cells of a Cat ... 169 



