131 
der the elementary nature of these substances as 
nearly the same, then the opinion of M. Geoffroy 
will come near to a true expression of the fact. It 
is, we think, much more remarkable, that M. Sene- 
bier, who saw all that he has-mentioned, and much 
mQre that we shall have to relate, was yet turned 
aside from the conclusion to which his experiments 
naturally led, by the influence of an hypothesis which 
had nothing better than a name for its support. 
382* BUT if the colour of green leaves depend, as 
we have supposed, on the predominance of alkaline 
matter (378.), that of white leaves may reasonably 
be presumed to arise from the deficiency of it ; and 
the experiments of M. Senebier prove that such is 
the fact. Not only did he find alkaline matter to be 
less abundant in etiolated than in green eaves, but 
to exist in a more neutralized state ; and may not, 
says he, this neutralization be produced by the 
union of the carbonic acid, in such leaves, with the 
alkali which they contain * ? This acid he actually 
found, by other experiments, to abound most hi etio- 
lated leaves t ; and his results are confirmed by those 
obtained by Davy (25.) and others. Since, there- 
fore, etiolated leaves not only contain less alkali than 
those which are green, but this alkali is neutralized, 
or even supersaturated, by a predominant acid, it is 
not to be expected that it should produce its usual 
* Mem. Phys. Chim. t. ii. p. l6'6- t ll>id. 1^9- 
T O 
