10 ; '-STUDIES ON APPLES. 



those f of Berard.^ ' The'air<in which the fruit was kept was examined 

 at shorter intervals than in the experiments of Berard, and this may 

 account for the disagreement of their results, though De Saussure 

 believed that the glass containers used by Berard were too small, so 

 that crowding or overheating may have taken place. 



De Saussure reiterated that green (unripe) fruits act on the air like 

 leaves, differing only in intensity of action, which is less in the case 

 of fruits. During the night oxygen disappeared and was replaced by 

 carbon dioxid, which was partly absorbed by the fruit, absorption 

 being less in free than in confined air. The fruits consumed, volume 

 for volume, more oxygen in the dark when they were very green than 

 when they approached maturity. On exposure to sunlight they gave 

 off part or all of the oxygen of the carbon dioxid which they had 

 absorbed in darkness, and used up all the carbon dioxid from the 

 atmosphere in which they were inclosed. Green fruits could even 

 remove the carbon dioxid from an atmosphere artificially charged with 

 several per cent of the gas. 



Couverchel 6 contributed two papers of much interest, in which the 

 ideas of several early writers on the subject are given. These ideas 

 were founded largely on theory rather than on experiment. From 

 the early work of Sennebierare quoted the following items of interest: 



The fruits which have yellowed in ripening are more succulent than green fruits, 

 are nearer decay, are more gummy than resinous, and are more soluble in water. 

 Perhaps the phlogiston may have less energy because it is more attenuated, the fiber 

 ioosens, the mass of the fruit increases, etc. 



Sennebier supposed that the fruit suffered a loss in phlogiston 

 (corresponding to a gain in oxygen). In a later work he says: "The 

 taste of fruits, at first bitter, becomes acid, then sweet. The astrin- 

 gent principle which appears before the formation of vegetable acid 

 changes to sugar by oxidizing." This writer considered that gallic 

 acid was the "unfinished" vegetable acid, completed by the oxygen 

 which it appropriated. " It is certain," he adds, " that the acids oxi- 

 dize more and more; for example, citric acid in green grapes passes, 

 by oxidation, into tartaric acid." This idea appears to have been cur- 

 rent among the chemists of the time, since it was specifically denied 

 by Fremy in 1844: in the case of grapes. (See Fremy, p. 11.) 



Other early writers are quoted by Couverchel, showing at what an 

 early date the functions and fate of the changing constituents of 

 growing fruits were studied and how varied were the notions con- 

 cerning them. For example, Lamarck and Decandolle considered 

 that oxygen arising from the decomposition of carbon dioxid acted 

 on the mucilage of the fruit, changing it to sugar. Berthollet thought 



a Loc. cit. 



&J. pharin. chim., 1821 (2), 7:249; and Ann. chini. phys., 1831 (2), 46:147. 



