THE PUBLIC WATER, MILK, AND FOOD SUPPLY 357 



mixing of some cheaper material with the original substance ; 

 second, the addition of coloring matter ; and third, the use 

 of chemical preservatives to keep foods from decay. 



Mixture. The substances used' in the first case are 

 usually not harmful to the human system, but the objection 

 to this method lies in the fraud thus practiced. Ground 

 coffee may be adulterated with chicory, ground peas, beans, 

 etc. ; unground coffee is adulterated less frequently. Butter 

 may be mixed with oleomargarine ; water may be added to 

 milk, or the cream removed; flavoring extracts and spices 

 are frequently adulterated. 



Coloring matter. There is a difference of opinion whether 

 there are ill effects in the body from all of the materials used 

 for coloring foods. But regarding the effect of many of 

 them there is no doubt, as they are known to be injurious. 

 There indisputably remains the fraud, as these colors are 

 used to give a false appearance to the foods containing them. 

 Coloring matters may be added to jellies made from cheap 

 substances so as to give them the same appearance as those 

 made from good fruits. They may be added to cucumber 

 pickles and tomato catsup to bring back the original color 

 which has been lost in the process of canning. Butter is 

 frequently artificially colored. And chopped meats which 

 are not fresh may have coloring matter added to give them 

 the appearance of fresh meat. 



Preservatives. The most dangerous kind of adulteration 

 is the use of chemical preservatives, because most of those 

 used are injurious to health. Among the more common 

 kinds are formaldehyde, benzoic, boric, and salicylic acids, 

 and their sodium salts, such as benzoate of soda. 



Milk is sometimes treated with preservatives, especially 

 in warm weather, to delay its souring. Formalin is the 

 substance generally used for this purpose. Milk is the chief 

 food of infants, and therefore it is specially important that 

 it should be pure and wholesome. At that early time in 



