223 
no other difference, in the conduct of the experiments, 
is stated, than that the plants were respectively placed 
in sunshine and in the shade. The atmosphere of 
the plants in sunshine, at the time of their death, be- 
tween the 5th and 6th day, contained -ny of oxygen 
gas *, which is probably much more than existed in 
the vessel placed in the shade at the end of the lOth 
day ; so that the cause of death, in the former case, 
could not have proceeded from the absolute deterio- 
ration of the air. Neither can we ascribe the death 
of the plants to the abstraction of moisture by the 
lime, as we had formerly supposed (43.) ; for it is 
not stated that the leaves had become dry, and their 
fall might take place from causes entirely independent 
of their desiccation (233.). Moreover, such a cause 
would have equally affected the plants which grew in 
the shade. 
504. As, then, neither the state of the atmosphere, 
nor the condition of the plants as to moisture, seems 
sufficient to account for their death, may we not sup- 
pose that the lime itself exerted some deleterious ac- 
tion in sunshine, which it did not produce in the 
shade ? This is rendered highly probable by the ob- 
servations which M. Braconnot has made on these 
very experiments. He contends, that the death of 
the plants was not owing to the privation of carbonic 
acid alone, but to the action of the lime itself in a 
state of vapour ; for he found, that if litmus-paper 
was suspended in a phial that contained moistened 
lime, it, in a short time, was changed to a blue colour, 
* Recherches Chim. p. 35. 
