THE PRESERVATION OF FOOD BY CHEMICALS. 409 



preservative, but its presence in foods is readily detected, and it gives rise 

 to characteristic effects upon the consumer. Furthermore, such foods are 

 subject to special taxation as alcoholic products. Its use as a food pre- 

 servative is therefore limited. 



Wood smoke has been employed for centuries in the curing of meats. 

 Its antiseptic properties probably depend for the most part upon creosote 

 and pyroligneous acid, constituents of wood smoke which are antiseptic 

 and also undoubtedly poisonous in sufficient doses. Smoking is a time- 

 honored custom, however, and the amounts of these substances actually 

 consumed with the smoked meat is doubtless exceedingly minute. 



SUBSTANCES ADDED TO FOODS TO IMPROVE THE APPARENT QUALITY. 

 Several chemical substances are employed in various foods to improve 

 the appearance, or to simulate the taste of a higher-grade product. In 

 some cases the presence of these agents is known to the consumer, and 

 desired by him; in other instances they are employed to deceive the pur- 

 chaser. Butter coloring is quite generally used to produce the color of 

 June butter the year around; nitrates bring about a pleasing red color in 

 cooked pickled meats; copper sulphate is used to give a more brilliant 

 green color to prepared vegetable foods; sulphites restore the red color of 

 freshly cut meat to meat far from fresh; saccharine devoid of food value 

 gives a taste resembling sugar to a variety of preparations at a great sav- 

 ing in cost to the manufacturer; carbonates of the alkalies or alkaline 

 earths added to milk, neutralize the acids resulting from bacterial decom- 

 position and so keep the milk sweet; inorganic acids added to weak 

 vinegar increase its acidity. Some of these practices are so universal and 

 so well known that they are no longer criticized, others, such as the use 

 of chalk in milk, are generally disapproved. 



LEGAL CONTROL OF THE PRESERVATION OF FOODS BY CHEMICALS. 



The desirability of legal regulation of the use of chemical food pre- 

 servatives is now generally recognized, but there is still considerable di- 

 versity of opinion concerning what this regulation should be. Few, in- 

 deed maintain that a substance exerting antiseptic action upon microorgan- 

 isms outside the body is wholly without influence, after ingestion, upon 

 the enzymes and bacteria of the normal digestive tract, even if we dis- 

 regard the possible effects of the substance after absorption. It seems 

 necessary to grant the existence of some effect, even though it be so slight 



