10 STUDIES ON APPLES. 
those of Bérard.“ The air in which the fruit was kept was examined 
at shorter intervals than in the experiments of Bérard, and this may 
account for the disagreement of their results, though De Saussure 
believed that the glass containers used by Bérard 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 ease 
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’ 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 Sennebier are 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 
loosens, the mass of the fruit increases, etc. 
Sennebier supposed that the fruit suffered a loss in phlogiston 
(corresponding to a gain in oxygen). Ina 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 galliec 
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 Frémy in 1544 in the case of grapes. (See Frémy, 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 
@ Loc. cit. 
’J. pharm. chim., 1821 (2), 7: 249; and Ann. chim. phys., 1831 (2), 46: 147. 
