THE SPECIAL SENSES 409 



4. A foreigner who speaks our language perfectly when at ease 

 often falls into his native speech when excited. Tell why. 



5. Why is the order for the closing of the eyelids, when we fear an 

 accident, not left to the cerebrum? 



6. If the cerebrum of a person were removed, and he lived, could 

 any of his functions go on? What ones could not? 



7. Why is the idea of goodness connected in our minds with clean- 

 ness? 



8. How does a baby learn to speak with a rough voice, or with a 

 pleasant one? How does it learn to speak one language rather than 

 another? 



9. Name several reflex actions of the external organs. 



10. Suppose that you have a bad temper; in the light of what you 

 have learned about habit, suggest how you could get control of your 

 temper. What would you suggest to a person who always " answers 

 back," as a way to cure himself of the habit? To one who uses 

 cigarettes? 



11. Why does your mouth water when you smell a good dinner? 

 How do the salivary glands know when to secrete the saliva? Does the 

 ''watering" of the mouth serve any good purpose? 



12. How are nerve impulses started, and to what organ are they 

 carried, when you "read over" your lesson for the first time? What 

 has occurred when you can recite it perfectly? 



13. Why ought the performing of experiments with hydrogen, in 

 the laboratory, to help you get a better idea of this gas than merely 

 reading about it? Give the reasons. 



409. The Special Senses. By the special senses we 

 mean touch, taste, smell, hearing, and sight. The organs 

 of the special senses are the skin, the mouth and tongue, 

 the nose, the ears, and the eyes. Each of these contains 

 afferent neurons that carry to the brain special messages 

 from the outside world. The eyes send light impulses, 

 the ears, sound impulses, the finger tips, feeling impulses. 

 As these impulses come to the brain, we, that is, our 



