224 
among the most important : and its immediate con- 
nection with our subsequent views of the theory of 
this function will, we hope, justify our attempt to 
give it all the additional evidence and illustration in 
our power. 
.623. Commencing with the seed, we endeavoured 
to shew (137.) that the carbon which it afforded to 
form carbonic acid, escaped from it in combination 
with the exhaled moisture* and therefore that the 
Union of this carbon with the surrounding oxygen 
did not take place while it properly formed a part of 
the vegetable substance. In support of this opinion, 
we alleged that the presence of oxygen gas was not 
necessary to abstract the carbon of seeds (133.) ; and 
we related some experiments of M. Huber, in which 
carbon was given out by seeds, and combined with 
the nitrogen of the atmosphere, after all its oxygen 
was consumed. 
624. Since that period, we have, in part, repeated 
these experiments, by placing successive quantities of 
steeped peas to germinate in atmospheric air, where 
they remained some time after all its oxygen was 
consumed. The residual air was then washed in 
lime-water to remove its carbonic acid, and it was 
afterwards mixed with an equal bulk of atmospheric 
air, previously deprived, also, of its small portion of 
carbonic acid. With this aeriform mixture a large 
phial was filled, in the usual manner, under water, 
and closely stopped. It was then kept inverted in 
water for several days, and a portion of it being af- 
terwards passed into pure lime-water occasioned in 
It a slight^ but very sensible discolouration. This 
