l8o ANSWERS TO PRACTICAL QUESTIONS 



henc i it is mainly digested in the stomach ; while vege- 

 table food needs to be thoroughly masticated and incor- 

 porated with the salivary mucus. 



29. Why is a child 's face plump and an old marts 

 wrinkled ? 



In the child the processes of nutrition are more active 

 than those of waste. The reverse is the case in old age. 



30. Show how life depends on repair and waste. 



(See Chemistry, page 34, et sey. ; and Physiology, page 120.) 



31. What is the difference between the decay of the teeth 

 and the constant decay of the body ? 



The particles of the teeth lost by decay are not 

 renewed, while in the body they are replaced as fast as 

 worn out. 



32. Should biscuit and cake containing yellow spots of 

 soda be eaten ? 



Certainly not. The alkali neutralizes the acids of the 

 alimentary juices, and thus impairs their functions, while 

 it corrodes and irritates the delicate mucous lining of 

 the digestive organs. 



33. Tell how the body is composed of organs, organs are 

 made up of tissues, and tissues of cells. 



(See Physiology, page 154, note.) 



34. Why do we not need to drink three pints of water 

 per day ? 



(See Physiology, page 133.) 



The amount of water one needs depends upon the 



