98 REPORT ON BOTANY, MDCCGXLI : 
is unjust to attribute to all the neglect of two. Chemistry 
has certainly been taken into consideration in the better 
systems of physiology ; but Botanists cannot be blamed, if they 
do not at once take every thing for granted that is told them 
by chemists. The author further says, in his indignation, — As 
soon as the mysterious vital power is presented to the phy- 
siologists in some phenomenon, they renounce their senses and 
judgment, &c., &c. Strange ! Finally, the author demands, that 
the bugbear, “ vital power,” as he expresses it, be assumed, 
to place substances together in such a manner, as to constitute 
a spiral vessel, a cell, a leaf, a blossom. The author then pro- 
ceeds to the assimilation of hydrogen in plants. He says, the 
solid part of the plant, the woody fibre, contains carbon and 
the constituents of water, or the elements of carbonic acid. 
We can suppose the wood to be produced from the carbon of 
the carbonic acid, which is combined with the elements of the 
existing water, under the influence of the light of the sun ; in 
this case, oxygen is given off as gas, and the carbon is assimi- 
lated in the plant ; or, what is more probable, the plant, under 
the same circumstances, containing carbonic acid, decomposes 
the water ; its hydrogen is assimilated with the carbonic acid, 
in order to form the woody fibre, whilst its oxygen is given off. 
The woody fibre contains carbon and the constituents of water ; 
there is, however, more hydrogen in the wood than corresponds 
Avith this relation ; hydrogen is situated Avithin the wood, in 
the form of chromule, AA^ax, oil, resin, &c., &c. It cannot be 
doubted, that hydrogen is assimilated by the plant from the 
water ; but it has not yet been explained how this is done ; 
the author only states conjectures, and does not enter into the 
reasons of the chemical combinations and decompositions. The 
assimilation of nitrogen, according to the author, takes place 
from the carbonate of ammonia in the atmosphere, which is 
carried down by the rain, and imbibed by the roots of the plant. 
Bain Avater, according to the author, contains carbonate of 
ammonia. This salt gets into the atmosphere through the 
medium of decaying animal and vegetable substances. This 
seems to be very correct. Gypsum, the author adds, is used 
as manure, because it decomposes carbonate of ammonia, and 
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