FOODS AND DIETARIES 343 



out nutrients from vegetable tissues, it is best to boil them rapidly 

 in a small amount of water. This gives less time for the solvent 

 action to take place. Vegetables should be cooked with the outer 

 skin left on when it is possible. 



Problem XLIII. ,i study of some forms of food, adultera- 

 tions. {Laboratory .Uamtal, Prob. XLIII.) 



ty Adulterations in Foods. — The addition of some cheaper sub- 

 stance to a food, with the view to cheating the purchaser, is known 

 as adulteration. Many foods which are artificially manufactured 

 have been adulterated to such an extent as to be almost unfit for 

 food or even harmful. One of the commonest adulterations is the 

 substitution of grape sugar (glucose) for cane sugar. Most cheap 

 candy is so made. Flour and other cereal foods are sometimes 

 adulterated with some cheap substitutes, as bran or sawdust. Prob- 

 ably the food which suffers most from adulteration is milk, as water 

 can be added without the average person being the wiser. By 

 means of an inexpensive instrument known as a lactometer, this 

 cheat may easily be detected. In most cities, the milk supply is 

 carefully safeguarded, because of the danger of spreading typhoid 

 fever (see Chapter XXIX) from impure milk. Milk is often 

 treated with preservatives which kill the bacteria in it and pre- 

 vent the milk from souring rapidly. Such preservatives are often 

 harmful to health. 



Coffee, cocoa, and spices are subject to great adulteration; 

 cottonseed oil is often substituted for olive oil; butter is too 

 frequently artificial ; while honey, sirups of various kinds, cider 

 and vinegar, have all been found to be either artificially made from 

 cheaper substitutes or to contain such substitutes. 



Pure Food Laws. — Thanks to the National Pure Food I>aw 

 passed by Congress in 1907, and to the activity of various city and 

 state boards of health, the opportunity to pass adulterated foods 

 on the public is greatly lessened. 



Impure Water. — Great danger comes from drinking impure 



water. This subject has already been discussed under Bacteria, 



N^here it was seen that the spread of typhoid fever in particular is 



due to a contaminated water supply. As citizens we must aid all 



