162 Progress of Foreign Science. 



on vegetation, which is now fully confirmed by his recent expe- 

 riments. 



" When I was occupied," says this able philosopher, " in my 

 researches on vegetation* , with the action of green fruits on the 

 atmospheric air, I admitted that they produced the same effects 

 as the leaves, or that they poured out like them oxygenous 

 gas, by the decomposition of the carbonic acid, with this dif- 

 ference that, in an equal volume, they decomposed much less. 

 My experiments on this subject indicate, that grapes in the 

 state of verjuice, and the green fruit of the solanum pseudo- 

 capsicum, exposed to the sun, and adhering to the plant and 

 soil, which make them grow, add oxygen to the air contained 

 in the vessel in which they are enclosed; whilst the^same fruits, 

 in circumstances otherwise equal, destroy the oxygen of the 

 vessel, when it contains hydrate of lime. This substance, by 

 absorbing the carbonic acid which they form, and that which 

 they receive from the soil, prevents the oxygen from making its 

 appearance, which would otherwise have been disengaged. 



" In the experiments which I published, the disengagement 

 of oxygen gas had not the same success when the fruits were 

 detached from the plant that bore them. Like the leaves, they 

 absorbed oxygen gas from the air in obscurity, replacing it in a 

 volume nearly equal to the fruit, by an equal quantity of car- 

 bonic acid gas; but in the sun they decomposed only in part the 

 acid gas produced during the night, whilst on the plant they 

 decomposed it altogether. This partial and purely accidental 

 difference depended evidently on the decay or loss of the vege- 

 tative force which a fruit must suffer when it is detached from 

 its plant, and which receives no nourishment; and this difference 

 ought not to affect the experiments which led to the conclusioa 

 that green fruits comport themselves in the air, as the leaves 

 do. These experiments offered, moreover, merely a confirma- 

 tion of the principle which supposes that the faculty of emitting 

 oxygen gas in the sun is essential to the green herbaceous parts 

 in a state of vegetation." 



M. Berard deduced from his experiments the remarkable 

 result, that green fruits, in any period of their growth, do not 

 comport themselves like leaves in sunshine ; that they do not 

 there decompose the carbonic acid gas ; that they do not there 

 disengage oxygen gas, and that the only action which thev 

 exercise on the atmosphere in every period of their vegetation, 

 is to transform its oxygen into carbonic acid ; he is even led to 

 believe that, in an equal time, green fruits cause the disap- 

 pearance of more oxygen in the sun than in the shade. 



M. de Saussure justly observes, that since the object is to 



* Pages .S7 and 129. 



