192 BIOLOGY AND HUMAN LIFE 



5. Relation of exercise to blood system 



Exercise and appetite Exercise and circulation 



Exercise and breathing Exercise and heartstrain 



6. Disorders of the blood system 



Heart defects Arterial defects 

 Sources Lack of elasticity 



Infections Hardening (arteriosclerosis) 



Strains Venous defects 

 Kinds Varicose veins 



Muscular Capillary defects 

 Valvular Walls too thin 



Bleeding easily 



QUESTIONS 



1. In what sense does the blood unify the body? 



2. How can you tell whether the blood at a wound comes from the 

 veins or from the arteries ? 



3. How should you stop the bleeding from a w'ound on the face ? 



4. What should you do to a wound besides stopping the bleeding? 



5. Is a cut more likely to clot when a person is "fighting mad" or 

 when a person is lying still ? Why ? 



6. How does being chilly interfere with good brain work ? 



7. What part does the blood play in the sick condition resulting from 

 constipation? 



REFERENCE READINGS 



McCarthy, J. D. Health and Efficiency, pp. 125-134. 



Hough and Sedgwick. The Human Mechanism, pp. 152-165. 



Harrow, Benjamin. Glands in Health and Disease, chap, xi, The Influ- 

 ence of the Ductless Glands on Growth and Metabolism. 



Williams, J. F. Healthful Living, pp. 235-251. 



Public Health Reprint 893. Methods of Administering lodin for Pre- 

 vention of Goiter. 



Red Cross, Woodcraft, or Scout manuals for first aid. 



