CHAPTER 16 • HOW DO GLANDS WORK? 



1 Do glands influence our abilities? 



2 Do glands influence personality? 



3 How can a slight change in one part of an organism bring 



about adaptive responses in other parts? 



4 How do gland substances reach other parts of the body? 



5 What good does it do living things to feel fear? 



6 Are all people naturally or instinctively afraid of the same 



things ? 



7 Can we learn to overcome fear or to control anger? 



8 Can people act against their instincts? 



9 Why do we learn more easily at some times than at others? 

 10 Can human nature be changed? 



When Abraham Lincoln was President of the United States, the country 

 was torn by civil strife. The entire population was constantly agitated by 

 strong feelings — bitterness and hatred, anxious waitings and eager hopes, 

 high elations and shattering disappointment. The President himself, with 

 all his patience, was subject to moods of depression. It was easy to give 

 good reasons why one should be angry at one time and joyous at another. 

 But nobody suspected that "glands" had anything to do with people's 

 feelings. 



In the following forty years much was learned from the study of patients 

 in hospitals and clinics, from experiments, and from the comparison of men 

 and women living in different regions under different circumstances. We 

 had already learned enough to suspect that some of President Theodore 

 Roosevelt's characteristics were related to glands, and he was often de- 

 scribed as "hyperthyroid". 



How can glands influence people's feelings or their behavior? What 

 are glands anyhow? What do they do? How do they produce effects in 

 other parts of the body? 



What Are Glands? 



The Humors Hippocrates, the most famous Greek physician, ad- 

 vanced the idea that the health of the body depends upon a balance of four 

 master fluids or "humors" within the body. Blood is one of these, the red 

 one; and the others were white, black, and yellow. For centuries this sup- 

 position guided the doctors in treating their patients. And it still shows itself 

 in our daily language, for we speak of a person's being in ill humor, or 

 being phlegmatic or melancholic — that is having too much white humor or 



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