128 THE VITAL PROCESSES 



Variety in the selection of foods for the table is an essen- 

 tial feature, but this should not increase either the work or 

 the expense of supplying the meals. Each single meal 

 can, and should, be simple in itself and, at the same time, 

 differ sufficiently from the meal preceding and the one 

 following to give the necessary variety in the course of the 

 day. The bill of fare should, of course, include fruits (for 

 their tonic effects) and very small amounts perhaps of sub- 

 stances which stimulate the appetite, such as pepper, mus- 

 tard, etc., known as condiments. 



Purity of Food. The fact that many of the food substances are 

 perishable makes it possible for them to be eaten in a slightly decayed 

 condition. Such substances are decidedly unwholesome (some con- 

 taining poisons) and should be promptly rejected. Not only do fresh 

 meats, fruits, and vegetables need careful inspection, but canned and 

 preserved goods as well. If canned foods are imperfectly sealed or if 

 not thoroughly cooked in the canning process, they decay and the acids 

 which they generate act on the metals lining the cans, forming poison- 

 ous compounds. The contents of "tin" cans should for this reason be 

 transferred to other vessels as soon as opened. 



Foods are also rendered impure or weakened through adulteration, 

 the watering of milk being a familiar example. The manufacture of 

 jellies, preserves, sirups, and various kinds of pickles and condiments 

 has perhaps afforded the largest field for adulterations, although it js 

 possible to adulterate nearly all of the leading articles of food. A long 

 step in the prevention of food and drug adulteration was taken in this 

 country by the passage of the Pure Food Law. By forcing manufac- 

 turers of foods and medicines to state on printed labels the composition 

 of their products, this law has made it possible for the consumer to know 

 what he is purchasing and putting into his body. 



Alcohol not a Food. Many people in ,this and other 

 countries drink in different beverages, such as whisky, 

 beer, wine, etc., a varying amount of alcohol. This sub- 

 stance has a temporary stimulating or exciting effect, and 

 the claim has been made that it serves as a food. Recently 



