ADVANCED BY LIEBIG- AND OTHERS. 3 
established by Faraday, that hydrogen and oxygen may be 
made to unite by a well cleaned plate of platina, seems ir- 
reconcilable with the idea that absorption is the mean of 
its accomplishment. But if absorption be not the cause in 
I the case of the plate, is it consistent to suppose it to be the 
cause in that of the sponge ? In this, as in most other cases, 
Liebig seems to overlook the all-important agency of elec- 
tricity in the phenomena of nature. I should infer, that the 
metal most probably acts by altering the electrical polarity, 
and consequent association of imponderable with ponder- 
able matter. 
Having inconsistently assumed that during the dehydroge- 
nation of alcohol by atmospheric oxygen in the presence of 
platina black, this powder is alternately endowed with the 
power to take it from the air, and to impart it to that, of 
which the attraction for oxygen, under the circumstances, 
is too feeble to take it from the same source, this popular 
theorist proceeds to make the inference that honey, mother 
of vinegar, and other substances promotive of acetification, 
act in the same way by absorbing oxygen from the air, 
and abandoning it to hydrogen. But if, agreeably to the 
view above presented, platina black does not act by absorp- 
tion, no argument, founded on the agency of that substance, 
will justify the idea that absorption avails in other cases ; 
and it should be recollected that platina black is most active 
when most free from moisture; while honey, yeast, mother 
of vinegar, and other substances which cause acetification, 
have no attraction for oxygen in the absence of water : more- 
over, that the necessity for moisture to the preparatory 
oxidizement of gluten, caseine, diastase, and other organic 
substances, which, by exposure in a humid state, acquire 
their capacity to act as ferments, is not explained. That 
water acts as a catalyzer, seems to have escaped notice. 
Before referring to the absorption of oxygen by honey, as 
a ground of explanation founded on the analogy of platina 
sponge, should not an explanation have been given by the 
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