glands, and other features that distinguish the two sexes among birds and 

 mammals. These are called secondary characters because they are not pri- 

 marily related to the reproductive function (see pages 391-393). 



One of the pituitary growth hormones stimulates the development of the 

 gonads. When these reach a certain stage, they discharge into the blood 

 their own specific sex hormones. One of these in turn acts upon a portion 

 of the pituitary gland so as to stop its further secretion of growth hormones. 

 As a consequence, the general growth of the body is likely to stop about the 

 time when reproductive organs mature. If their maturing is delayed, gen- 

 eral growth may continue further. 



What Have the Hormones to Do with the Feelings? 



Hormones as Unifiers During an emergency the appearance and the 

 behavior of a person (or of any other animal) change decidedly. The in- 

 ternal organs also change their action. Such situations arouse distinct feel- 

 ings. You feel a tingling in the skin, or you feel a difficulty in breathing. 

 You feel your heart thumping or perhaps some of the arteries in the head 

 throbbing. In addition to such feelings, however, there are others which we 

 cannot so clearly locate in any one part of the body. When you are fright- 

 ened, for example, you are frightened all over. When you are angry, you 

 are angry all over. When you are glad, you are glad all over, not merely in 

 the eye that sees the pleasing object or reads the happy news. Whatever 

 happens, you are normally all set, to take it — or to fight it, or to run away. 



Organic Sources of Emotions In general, emotions accompany the 

 organic processes that have to do with keeping alive or with preserving the 

 species. In the case of nutrition, for example, we may become so hungry 

 that we are driven to get food through special effort. We cannot keep quiet, 

 and we get no rest or satisfaction until food is obtained. If the hunger 

 makes us do somediing, we speak of the emotion as a motive, or drive. In 

 fact, the word emotioji means that which moves one to action. There may 

 be great discomfort or dissatisfaction, a desire for something, and finally a 

 deep satisfaction when the desire is fulfilled. We say in such cases that the 

 emotion is one of relief from a previous strain. 



Joy and Sorrow Agreeable emotions are associated with the healthy 

 workings of internal organs, with the satisfying of desires, and with activi- 

 ties that lead toward such satisfying. Merely hearing sounds or swinging 

 the arms, or merely shouting or walking may yield such satisfactions. Dis- 

 agreeable emotions are usually aroused by internal strains or by any inter- 

 fere?ice with desire or activity. If the urine is retained too long in the 

 bladder, if somebody blocks your path, if your wishes are denied you, un- 

 pleasant feelings are aroused. Even holding a baby's head firmly, without 



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