76 FOOD MATERIALS 



important articles of diet because they contain large 

 amounts of cellulose. Although this cannot be digested, 

 yet it is valuable in that it furnishes a considerable 

 residue in the intestine, thus insuring a regular onward 

 movement of the bowel contents. 



Dangers of raw vegetables. Raw vegetables, such 

 as radishes, lettuce and celery, are often dangerous to 

 health, more especially in European countries, because 

 animal excretions are used to fertilize them. Many 

 cases of dysentery, typhoid and other diseases have been 

 traced to this source. They should therefore never be 

 eaten unless they have been previously thoroughly 

 washed, or scraped and rinsed under running water. 



Potatoes. Common or white potatoes have long been 

 recognized as the most valuable of all cheap vegetables, 

 because they contain considerable nutriment and furnish 

 the salts necessary to maintain health. In addition, 

 they are always appetizing and can be kept from one 

 season to the next. 



Fruits. Besides cereals and vegetables, plants fur- 

 nish us with another most important and attractive kind 

 of food, namely, fruits and nuts. Juicy fruits contain 

 large amounts of fruit or grape sugar, together with 

 a considerable amount of cellulose and some starch. 

 Melons and grapes are particularly rich in sugar, 

 bananas in * starch. Nuts contain large amounts of 

 hydrocarbon and proteid and thus resemble meat in 

 composition. Like vegetables, fruits also contain the 

 acids and salts which are so important for health. 

 They should be used freely in all diets, either raw or 

 cooked. 



Preserved fruits. Fruits are prepared for use out 

 of their season, by being dried, preserved, or canned. 

 Dried fruits are almost as valuable as fresh and are 



