9 



vegetables and fruits, such as hops, herbs, peaches, grapes (raisins and currants, for 

 example), or the peel of oranges and lemons. The result is to render the substance of the 

 food too dry to allow any form of life to exist upon its surface. It is to protect from 

 moisture in the air that groceries are stored in tins and roots are buried in dry earth. 



(3.) Food can be immersed In Brine, Sugar, Vinegar, or Alcohol. A strong solution 

 of salt has a twofold preservative effect. It extracts water from meat or fish, for 

 instance, so that their flesh is unsuitable to germ-growth ; and it also removes some 

 of the nutrient constituents present in the food, leaving it unpalatable to micro- 

 organisms. 



Thick syrups and vinegar are also unfavourable to their development. Moulds loill 

 grow on the surface of both substances, but the delicate fibres are killed when in contact 

 with an acid, neither can they push their way down into a dense substance, such as a 

 thick syrup. 



Alcohol hardens food immersed in it, by extracting the moisture, and at the same 

 time renders them unpalatable to any form of decay. 



(4. ) Foods can be preserved by being highly xpiced or strongly favoured with Herb*. 

 It is believed that certain bitter principles, acids and oils, are present in spices and 

 herbs, rendering the foods with which they are mixed unpalatable to micro-organisms. 

 But, once again, a 



Note of Warning 



must be sounded. The pungent flavour of these favourite food-preservatives may be 

 employed to mask the first stages of decay by unscrupulous tradesmen. Hence highly 

 seasoned potted meats or sausages should be regarded with suspicion, unless their 

 source and mode of preparation is known to the purchaser. 



Drawback* to each of these Methods of Food-prf serration 



are found in that they affect the flavour and, more important still, they affect in some 

 degree the digestibility of the substances for the preservation of which they are 

 employed. 



The change of flavour is often pleasant ; rarely, if ever, objectionable ; neither is 

 the second drawback really serious when preserved foods form only a part of the diet 

 of adults in good health who are leading an active life. For children they should 

 always be used sparingly, and ought to be well combined with fresh milk, vegetables, 

 and eggs, as their nutritive properties are usually affected as well as their digestibility. 



When, as in some climates, foods thus preserved necessarily constitute the sole 

 source of supply, previous soaking in cold water and careful cooking minimize the risks 

 to digestion, or other forms of ill-health, liable to result. 



(5.) Food* can be preferred by the U*e of Chemicals. Different forms of borax, 

 formalin or formaldehyde, salicylic acid, etc. , all retard the decomposition of food. They 

 are so easy of employment that, in the case of perishable articles, such as milk, cream, or 

 sausage-meat, the temptation to use them is often irresistible. No external alteration in 

 flavour or appearance draw attention to 'their addition to milk, for example ; but, 

 unfortunately, they seriously interfere with the process of digestion, cause much 

 dyspepsia, and, in rare cases, loss of life. 



Why Chemical Preservatives interfere with Digestion. 



The putrefaction of food is due, as has been said, to a process of fermentation 

 caused by the activities of the micro-organisms of decay. Strange as it may sound, 

 digestion within the body is due to a corresponding process, far too technical and 

 complicated to be entered into here. But the fact must not be overlooked that when 

 such antiseptics as boracic acid or formalin are added to foods to prevent the 



