SOME LESSONS ON THE HUMAN BODY 5 



the pharynx, food and drink are beyond a person's control. 

 Their movement along through the remaining thirty or 

 more feet of the food canal is due to the vigorous activity of the 

 muscular coats of the oesophagus, stomach, and intestines. 



Taste and smell add much to the enjoyment of living. 

 But the distribution of the nerves of these two senses in the 

 nasal and mouth cavities indicates that their primary pur- 

 pose is to give warning against the introduction into the body 

 of food, drink, or air that is unwholesome or harmful. Not 

 all harmful substances have a bad taste or odor, nor are all 

 substances with disagreeable taste or odor harmful. How- 

 ever, the products of decay in foods when not disguised by 

 spices and flavorings are likely to give evidence of their 

 presence by an unnatural odor or taste. 



The tonsils are peculiarly exposed to infection. Their 

 location in the throat is such that they are in contact with 

 the air breathed, and with food and drink on its way to the 

 stomach. Their structure, too, is such as to make them sus- 

 ceptible to attacks of germ diseases. Any " soreness" of the 

 throat, and any "patches" upon the tonsils, may necessitate 

 prompt medical treatment. Many of the fatal ailments of 

 childhood manifest themselves in their earlier stages by an 

 inflamed condition of the throat, and more or less of swelling 

 and soreness there. All "colds" should be regarded with 

 suspicion, and proper care and precautions taken from 

 their first appearance. 



Although air is made to pass in and out of the mouth when 

 talking and singing, and when playing upon some musical 

 instruments, in all ordinary breathing the air should pass to 

 and from the lungs through the nose. In this way cold air 

 becomes somewhat warmed before reaching the lungs. 

 Dust present in the air is largely stopped in the nose, collect- 

 ing on the surface of the moist mucous lining of the nasal 

 cavity and on the hairs just inside the nostrils. 



