26 



HUMAN PHYSIOLOGY 



CHAP. 



contain salts, acids, and sugar. They are not especially 

 nourishing. 



4. Nuts contain a large amount of proteid and fat, 

 which makes them valuable as articles of diet. They 

 must be well chewed and eaten in small quantities, for 

 they are rather difficult to digest. The Germans say 

 that nuts and cheese are "gold in the morning, silver 

 at noon, and lead at night." 



30. Hygiene. The foods we eat, the water we drink, 

 and the air we breathe require careful attention, as we 

 shall learn later. Places where foods are kept should 

 be clean and well ventilated. How often are the pantry, 

 the ice box, and the cellar sadly neglected! Air, water, 

 milk, and meats that are impure, and fruits artificially 

 ripened or overripe, are often the causes of diseases. 

 We cannot be too careful as to the conditions of the 

 foods we take into our systems. 



FIG. 9. Trichinae (Buchholz) : A, trichinae, as seen in a muscle of a young 

 man who died of trichinosis ; B, a single trichina magnified. 



31. Value of Cooking. -Why do we cook foods? Some 

 will say because they taste better and look more at- 

 tractive when cooked. That is true ; but there are other 



