SALT AS A PRESERVATIVE 165 



The flavor is much changed, and too large a quantity of 

 salt meat is not wholesome. Moreover, salt somewhat 

 changes the physical nature of food, so that it is not 

 quite so easily digested. Salt foods, therefore, cannot 

 wholly take the place of fresh foods. Experience has 

 shown that when used in large quantities and unaccom- 

 panied by plenty of fresh food they give rise to a kind 

 of digestive derangement known as scurvy, a trouble fre- 

 quently met with among sailors who hav^e subsisted too 

 largely upon salty foods. Nevertheless such foods are 

 very useful, and if a quantity of fresh food is used with 

 them they may be used very advantageously as part of 

 our diet. In preparing such foods for the table they 

 should be soaked in water to remove as much of the salt 

 as possible. 



Vinegar. Acetic acid is another material used legiti- 

 mately for the preservation of certain kinds of food prod- 

 ucts. In its best known form, vinegar, it is the basis 

 of the preservation of all kinds of pickles. The acetic 

 acid in these cases serves two purposes : (i) It gives a new 

 flavor to the material, rendering it very sour. (2) It pro- 

 tects the product almost totally from the action of bacteria. 

 The pickling of cucumbers has become a great industry, 

 green cucumbers being more extensively used for the pur- 

 pose than any other material. The vinegar is frequently 

 mixed with spices, both for the purpose of added flavor 

 and to aid in the preservation. Although pickled vegetables 

 keep well, they do not keep indefinitely. Pickle brine 

 sometimes becomes covered with a scum composed of bac- 

 teria, and the pickles themselves may grow soft from decay. 

 If the pickles are taken out and boiled for a few minutes, 



