192 THE HUMAN MACHINE 



3. Of what use is the skin to man? 



4. Would the skin serve the same purposes in the frog as in 

 man? 



5. Name the functions of muscles. 



6. How do muscles work? Explain fully. 



7. Explain the difference between a voluntary and an involun- 

 tary muscle. 



8. What effect would working of the muscles have upon heat 

 within the body? Explain. 



9. What effect might muscular work have upon the skin? 



10. Why are the muscles arranged in pairs? 



11. Name three uses of the skeleton. 



12. What attaches muscles to bones? 



13. What is a lever? Give examples. 



14. Show how some one part of the body might illustrate the 

 action of three classes of levers. 



15. Of what use are the joints? 



16. Explain the difference between a break and a sprain. 



17. What is the body cavity? 



18. Which sets of organs are found entirely in the body cavity? 



19. Which organs are found partially in the body cavity? 



20. Why might the nervous system be called the " director of 

 the body"? 



REFERENCE BOOKS 



Hunter, Civic Biology, Chap. XVIII. American Book Company. 



Hunter, Elements of Biology, Chaps. XXXI, XXXII. American Book Company. 



Hunter, Essentials of Biology, Chap. XXIII. American Book Company. 



Davison, Human Body and Health (Advanced), Chap. XVII. American Book 

 Company. 



Goldmark, Fatigue and Efficiency. Charities Publication Committee. 



Gulick, The Gulick Hygiene Series. Ginn and Company. 



Gulick, Physical Education by Muscular Exercise. P. Blakiston's Son and Com- 

 pany. 



Hall, Elementary Anatomy. American Book Company. 



Halliburton, Kirkes Handbook of Physiology. P. Blakiston's Son and Company. 



Hammarsten, Textbook of Physiological Chemistry. J. Wylie and Son. 



Hawk, Practical Physiological Chemistry. P. Blakiston's Son and Company. 



Hough and Sedgewick, The Human Mechanism, Chap. II. Ginn and Company. 



Howell, Physiology. W. B. Saunders. 



Hutchinson, Exercise and Health. Outing Publishing Company. 



