^4 M. De SaussUre on the Injkience of Green Fruits 07i the Mr. 
that green fruits decompose much less carbonic acid than green 
leaves in the sun, but much more than when they approach ma- 
turity. 
From the foregoing experiments, the author concludes, gene- 
rally, that green fruits act upon the air, both in sunshine and 
in darkness, exactly like green leaves, but in a smaller degree: 
that, during the night, they cause the oxygen of their atmos- 
phere to disappear, and replace it by carbonic acid, which they 
in part absorb, but that this pov/er is exerted in a less degree as 
the fruit approaches maturity : that, on the contrary, when ex- 
posed to the sun, they set free, in whole or in part, the oxygen 
of the carbonic acid absorbed through the night, and leave not 
a trace of this acid gas in their atmosphere : that green fruits, 
detached from the plant, and placed alternately in sunshine and 
in darkness, produce little or no change, either in the purity or 
volume of their atmosphere : that in sunshine, fruits also possess, 
like leaves, the power of decomposing carbonic acid, when add- 
ed artificially to their atmosphere, but that this faculty of de- 
composing carbonic acid diminishes as they approach maturity. 
Beside these conclusions, which seem to be fully warranted 
by the experiments recited above, M. De Saussure seems to 
think, that, in their sour stafe, green fruits assimilate a portion 
of the oxygen of the carbonic acid which they decompose ; while, 
as they approach maturity, no such assimilation of oxygen takes 
place. And thus the passage from the acid to the saccharine 
state appears to shew, that the acidity of the green fruit has re- 
lation to the fixation of atmospheric oxygen, and that this acidity 
disappears when the fruit derives only carbon from the air. 
The author believes also, that, during their growth, fruits ap- 
propriate oxygen and hydrogen, the elements of water, by 
causing that fluid to lose its liquid state. These opinions must 
be regarded as resting on more doubtful evidence. 
In concluding his essay, M. De Saussure suggests some cau- 
tions in conducting the experiments, the neglect of which may 
have given rise to the erroneous results obtained by M. Berard. 
The volume c)f air employed in these experiments on fruits 
should exceed thirty or forty times that of the fruit ; and the 
heating power of the solar rjiys should be moderated. If these 
precautions are neglected, many fruits vitiate the air, even in 
