FOREIGN AIVD MISCELLANEUS NOTICES. 



ever, are not of this description ; their skins are 

 so porous and open, that they very soon allow 

 the air to pass into the interior of the fruit, and 

 consequently it is impossible to preserve them 

 by drying. 



The immediate consequence of air coming in 

 contact with the pulpy matter of ripe fruit, is 

 that the azotised matters begin to absorb oxy- 

 gen, and decompose; then the sugar, starch, 

 and gum are acted on; the flavor is rapidly de- 

 stroyed, sometimes spirit is formed, the sugar 

 simply undergoing the vinous fermentation; at 

 other times, the change goes on more rapidlj', 

 and tlie fruit soon becomes putrid. All these 

 effects may be easily observed, by watching the 

 ripening of any of the common varieties of 

 fruit. The drying up of ripe grapes, which 

 are left to hang with their skins uninjured, and 

 the immediate change whicli occurs if the skin 

 is injured or punctured, is familiar to every 

 one. The rapid change which takes place in 

 ripe Gooseberries, when the skins burst, and 

 which, in the first instance, is a mere case of 

 common vinous fermentation, is also well known. 

 The injury which all fruit sustains from bruises, 

 though it often does not produce the same ef- 

 fect, is yet in chemical nature very similar to 

 that which occurs in the gooseberry. The cause 

 of the evil in all cases is the oxygen of the air; 

 and the mode in which it acts consists in the 

 skin or cuticle being destroyed or injured, so 

 tliat the air finds an easy entrance through the 

 damaged part. In the case of delicate and thin 

 skinned fruits, they are so porous that the air 

 enters on all sides, as soon as they are fully 

 ripe, and even though they are not in any way 

 injured, and this constitutes the chief difficulty 

 in preserving them. 



The fresh juice of the grape readily ferments, 

 as soon as it is ex[)osod to the air, but the juice 

 of a raisin or half dried grape no longer has 

 the power of doing so, because it contains too 

 much sugar to ferment. A weak solution of 

 sugar, under favorable conditions, soon begins 

 to ferment; whilst a strong one is unable to en- 

 ter into the vinous fermentation. It is in part, 

 on this fact, that the common mode of preser- 

 ving fruits by means of sugar depends. In 

 making preserves, too, the fruit is heated, and 

 heat, by rendering the vegetable albumen solid, 

 makes it less likely to decompose. The pre- 

 servative influence of heat on all forms of or- 

 ganic matter is well known; the value of heat 

 in preventing the decomposition of food gene- 

 rally, was minutely detailed by Appnrt in 1810, 

 for which he was rewarded by the French 

 Government with a sum of twelve thousand 

 francs. 



But both heat and sugar, though no doubt 

 very useful agents in the preservation of fruit, 

 are very far from being quite satisfactory ; and 

 though, by their use, the fruit may be prevented 

 from undergoing actual fermentation, yet more 

 of the flavoring matter of the fruit is 

 destroyed or lost. What is wanted is 

 means of preventing the decomposition of the I 



fruit, without the use of any substance which 

 could injure its flavor, either by the addition 

 of a new flavor or the destruction of the natural 

 one. After what has been done already in the 

 storing and preservation of some sorts of fruit, 

 and the improved modes of keeping it which 

 have been devised, we do not altogether des- 

 pair of a satisfactory mode of preserving the 

 more delicate kinds being discovered, although 

 most of the recorded experiments which have 

 been made with that view are certainly not very 

 encouraging. The experiments usually referred 

 to on the preservation of fruit by chemical 

 means, are some which were made by Dr. 

 Henry in 1776, and described in the fourth 

 volume of Dr. Priestley's '•' Essays on Air.'' 

 The fruit in these experiments was suspended 

 in carbonic acid, so that it was kept in an at- 

 mosphere containing no free oxygen. A bunch 

 of grapes expo.sed to carbonic acid remained 

 fresh and plump for six weeks, whilst a corres- 

 ponding bunch placed near it in a similar ves- 

 sel, containing common air, was quite mouldj' 

 in three weeks. A second experiment was 

 made with some ripe and rather stale straw- 

 berries, which had been gathered the day be- 

 fore; the following day those which were ex- 

 posed to the air had lost their taste, whilst the 

 fruit kei)t in cai-bonicacid, " had become more 

 dry, but was fragant and well tasted; their 

 fragrancy was even thought to be improved." 

 On the fourth day, those in air became quite 

 musty and mouldy, whilst those in carbonic 

 acid were some of them firm, and had still a 

 moderate degree of flavor at the end of eight 

 days- 



In this experiment of Dr. Henry's there are 

 two points which were decidedly against the 

 preservation of the fruit, namely, that the 

 fruit was already stale at the commencement 

 of the trial, and that the carbonic acid employ- 

 ed was not pure, but contained common air. 

 A number of similar experiments have since 

 been made, the general result of which has 

 been, that though the fruit kept well, it wholly 

 lost its flavor; but we do not think that there 

 is any reason to despair of ultimate success. It 

 is plain, from all the trials which have been 

 made, that it is easy to prevent the decay or 

 fermentation of fruit; the difficulty is rather 

 to preserve its fine flavor, and prevent it from 

 becoming tasteless and insipid. "When an ap- 

 ple is bruised, the part thus injured soon turns 

 brown, decay commences, it becomes mouldy, 

 and the whole fruit soon rots; and this decay 

 easily spreads from one apple to another. If 

 a little hole is cut through the skin of a sound 

 apple, and a small piece of a rotton one is in- 

 serted under the skin, the sound fruit will soon 

 be brought into a state of decay; but if this 

 is done in a jar of carbonic acid, no such effect 

 will take place — the sound apple will remain 

 fresh, even though there is a portion of decay 

 ed apple in contact with it. The flavor of 

 is apt to be spoilt, not merely from the 

 the peculiar volatile oil which it contains 



