KEPORTS OF AUXILIARY SOCIETIES. . 361 



an oxidizing agent, and the most of its influences are the opposite of those of 

 ozone. Moreover ozone is not a preservative, so that this trade-name, ozone, is 

 adopted with no regard to the use of the chemical term. Sulphurous acid is a 

 most potent antiseptic and preservative, of use as old as history. Its salts, the 

 sulpliites, are employed to prevent the fermentation of cider. It is cheap 

 enough, a pound of sulphur at three or four cents furnishing sulphurous acid 

 enough for the treatment of hundreds of pounds of perishable material. There 

 are three difficulties, however, in the way of its success in preserving fruits. 

 First, if not confined in strictly air-tight vessels it escapes and leaves the fruit 

 to decompose as surely as though it had not been applied. Second, if air is 

 not excluded it oxidizes to sulphuric acid, nearly valueless as a preservative, 

 and the fruit is left unprotected. Tliird, while the sulphurous acid is retained 

 its suffocating vapor is both ofFensireand hurtful, its oxidized product is astrin- 

 gent, disagreeable, and unsuitable to food, and it is hardly practicable to expel 

 it so as to avoid its oxidation. Another agent which has been tried in the 

 preservation of fruit is borax. It is a potent preservative but probably cannot 

 be taken in concentration sufficient to be eflfective without being objectiouable 

 to taste and health. Still another, and perhaps the most promising preserva- 

 tive is salicylic acid, much praised for keeping milk and other foods, — an agent 

 that does not vaporize, can be taken in considerable quantities with but little 

 effect on the system, and is not very expensive. There is, however, a lack of 

 evidence that it can be used properly to keep fruits. 



In considering the influences which preservative methods have upon the 

 value of fruits, Ave should bear in mind the lollowing named constituents: 



a. Sugars and starch products (common to other vegetable foods). 



h. Pectous substances and gums. 



c. Acids, tannin, glucosides. 



d. Ethers and other flavoring substances. 



In cooking, all of these substances are altered, and the ones most distinctive 

 to fruits are so changed as to no longer retain the especial value of fruit as a 

 promotive of digestion and a nourishment to the body. The pectous substan- 

 ces lose no small share of their distinctive service, as antiscorbutics, and pro 

 moters of nourishment, in being cooked. Acids are modified less seriously; 

 but they suflfer alteration. Flavors are driven off. Cooked fruit in some res- 

 pects corresponds to over-ripe fruits. 



The changes in dr^-ing, if it be done rapidly, with brief exposure to air, are 

 not so generally injurious as in cooking, but are still hurtful in some degree. 

 The flavors are dissipated, and the pectous substances, frail ana alterable as 

 they are, after drying, refuse to resume their exact previous state. With 

 long exposure to air the changes of over-ripening and incipient decay are 

 obtained. But it should be admitted that fruits rapidly dried at low tempera- 

 ture present many claims to comparative favor. 



The effect of sugar added to preserve fruits is hot objectionable, unless it 

 becomes an objectionable article in itself. Sugar does not neutralize or modify 

 the acids, nor does it cause chemical changes of the other constituents. But 

 sugar is in itself a heavy article of diet, not by any means always favorable as 

 an accompaniment of fruit. If the sugar is desired as an addition, it; is very 



burn on a plate in a closeil and air-tight barrel, V)Ox, or compartment containing the articles to be 

 preservetl. It will burn until the articles are fully preserveil, when it will stop burning of itself, 

 SI) that what is left can be useil again. Upon analysis 1 lind the mixture to consist of three parts 

 of sublimed sulptiur ami two parts of powdered charcoal, with a very little ground cinnamon." 

 —[From report of A. B. Prescott in Detroit Post and Tribune, December, IStJl.j 



