CHAPTER XIX. 

 HYGIENE OF THE NERVOUS SYSTEM. 



1. Introductory. The nervous system is so closely 

 connected with all other parts of the body that any- 

 thing which injures them can hardly fail to hurt it. He 

 who desires an active healthy nervous system and a 

 vigorous cheerful mind, must strive to keep muscles and 

 digestive, circulatory, and respiratory organs in health. 



On the other hand it should be borne in mind, that 

 nearly every function of the body is dependent on the 

 nervous system for its proper performance. It sets at 

 work the muscles which move the jaws, and the glands 

 which secrete saliva; controls the oesophagus in swallow- 

 ing; excites the glands of the stomach, and makes its 

 muscular coat mix the gastric juice with the food; it 

 governs the secretion of pancreatic juice and bile, which 

 turn the chyme into chyle; makes the muscular coat of 

 the intestine drive the digesting mass along that tube, 

 and controls absorption by its lacteals and blood-vessels; 

 it regulates the beat of the heart, and the diameter of 

 the arteries, and, thus, the blood-flow to every organ; it 



i. What is said of the connection of the nervous system with 

 other parts of the body ? What must one do who desires an active 

 nervous system and mind? What should also be borne in mind? 

 Give illustrations of the action of the nervous system in preparing 

 food to enter the stomach. In controlling its digestion in the stom- 

 ach. On conversion of chyme into chyle? On the movements of 

 the intestine? On absorption? On the blood-flow? On excretion? 



