526 



FOREIGN NOTICES. 



Fruits do not act on the air in the same manner 

 as leaves do : the results of the action of the former 

 (both in liii'ht and darkness) are at every instant of 

 their formation and j^rowth, to suffer a loss of car- 

 bon ; which, combining with the oxygen of the at- 

 mosphere, forms carbonic acid. The loss of car. 

 boll is essential to the ripening of the fruit ; for, if 

 the latter be placed in an atmosphere deprived of 

 oxygen, the function of throwing out carbon will 

 become suspended, the ripening stopped, and if the 

 fruit remain attached to the tree or plant, it will 

 dry up and die. 



Fruits which are enclosed in shells, however, 

 may and do ripen ; for the membranes which form 

 the husk are naturally permeable to the air : in- 

 deed, the communication between the external and 

 internal air is so free, that both have always been" 

 found to be of uniform composition ; that is, when 

 analysed, the atmosphere within the shell has fur- 

 nished the same relative quantities of oxygen and 

 nitrorjen as the air which we breathe. 



When fruits separated from the tree (even though 

 capable of completing their own ripening) are 

 placed in atmospheres or media deprived of oxy- 

 gen, they will not ripen ; the power of ripening, 

 however, in such case, is only suspended, and may 

 be induced to act, or be re-established, by placing 

 the fruit in an atmosphere capable of taking carbon 

 from it. If the fruit, however, remain too long in 

 the deoxygenated situation, it will have lost the 

 power of ripening : even though it preserve nearly 

 the same external appearance. 



From these facts the inference is plain, but high- 

 ly important, viz : that most fruits and especially 

 those which do not require to remain long on their 

 parent trees, may be preserved for a considerable 

 time ; and thus their utility and the pleasure which 

 they afford be prolonged. The most simple process 

 consists in forming a paste of lime, sulphate of iron 

 and water, placing the same at the bottoms of 

 glass or stone bottles, or jars ; and then introdu- 

 cing the fruit pulled a few days before it would 

 otherwise have become ripe. Such fruits, howe- 

 ver, are to be kept from the bottoms of the bottles 

 or other ves.sels, and as much as possible from each 

 other: at the same time care must be taken to 

 close the bottle or jar with proper corks and ce- 

 ment, either with or without bladders or tin covers, 

 according to circumstances. Persons at all ac- 

 quainted with chemistry, will perceive that fruits 

 thus placed, are situate in an atmosphere entirely 

 freed from oxygen, (which has been absorbed by 

 the paste,) and, consequently, that they may be 

 preserved for a longer or shorter space of time, 

 according to their nature : Peaches, Apricots, 

 Prunes, and several species of plums, from twenty 

 days to a month ; Pears and Apples for full three 

 months. If either of these fruits be withdrawn 

 from their confinement, after their respective peri- 

 ods, and be exposed to the air, they will ripen ex- 

 tremely well ; but if these periods be much exceed- 

 ed, they will undergo partial alteration and will 

 not ripen at all. 



It is well known that when ripe fruit is long 

 exposed to the air, it will rot and decay ; in such 

 cases the fruit first changes the oxygen of the sur- 

 rounding air into carbonic acid gas, and then the 



same gas is evolved from its own substance in a 

 large quantity. Indeed, the presence of oxygen 

 gas is necessary to tiie rotting or decay of fruits ; 

 for, when it is absent, a different change takes 

 place. When the fruit cannot ripen except on the 

 tree, its ripening is not caused by any chemical 

 change of its substance, whilst si ill green; but by 

 the change or addition of neiv substances furnished 

 to it by the capillary vessels of its parent stem ; and 

 it is a remarkable and well ascertained fact, that 

 when fruits appear to have lost the acid taste and 

 qualities which they possessed in their unripe state, 

 it is because that taste is hidden by the large quan- 

 tity of sugar which they receive during the process 

 of ripening: 



In those fruits which ripen after separation from 

 the tree, likewise, the quantity of sugar is found 

 considerably to increase : in such cases, however, 

 it must be formed at the expense of the substances 

 previously com/'osing the fruit. Gum, lignin, and 

 water, are the only substances present ; the propor- 

 tions of which diminish during the process : it is, 

 i therefore, natural for us to conclude, that it is 

 those portions of these substances which have dis- 

 appeared, that have been converted into sugar ; 

 and as the lignin contains the greatest quantity of 

 carbon, we must conclude that it is from it, the ox- 

 ygen takes ihe carbon in order to form carbonic 

 acid — a change so essential in the ripening of fruits. 



It is difficult to suppose that in those fruits which 

 ripen early on the tree, all the sugar shovXA be sent 

 into the fruit from the plant : it is much more pro- 

 bable that the substance of the fruit acts upon the 

 air — or vice versa — and thereby forms sugar, like 

 those fruits which have been separated from their 

 parent stems ; but not in sufficiently large (juantity 

 to render them identical in quality. In such cases, 

 it is necessary that recourse should be had to the 

 tree itself, to complete the process of ripening. 



In conclusion, it remains to be stated, that the 

 alteration which the lignin undergoes during the 

 process of ripening, or saccharification, continues 

 during the decay of the fruit, under any circumstan- 

 ces. During the process of decay, the lignin be- 

 comes brown, and its decomposition, as well as 

 that of the gum and the water, occasions the form- 

 ation of comparatively large volumes of carbonic 

 acid gas. The sugar also, (if any exist.) becomes 

 decomposed at this time ; and, to its disappearance^ 

 in a great measure, is to be attributed the peculiar 

 taste of decayed or rotten fruits. The sugar, du- 

 ring its decomposition, likewise, doubtless gives 

 rise to the formation of carbonic acid ; a great part 

 of which, combining with the hydrogen evolved 

 from the decomposing water, forms carburetted hy- 

 drogen, which is the main source of that ill or mi- 

 asmatic taste and smell, so characteristic of veget- 

 table putridity. The Gardener. 



The Last of the Superlatives. — The follow- 

 ing unique description of the new Dahlia, sent out 

 this season by the Metropolitan Union of Florists, 

 London, (taken from their circular,) is the best spe- 

 cimen of floral grandiloquence that we have yet 

 seen. Certainly Holland, in the days of the tulip- 

 mania, produced nothingmore exaltee. Fortunate- 

 ly, buyers in England are able to look to the opin- 



