REPORT ON CHEMISTRY. 
497 
upwards of fifty other principles have been described, pos¬ 
sessing the properties or virtues of the plants from which they 
are extracted, but exhibiting neither acid nor alkaline proper¬ 
ties. 
While our knowledge of ultimate principles and their atomic 
constitution has thus been extending, several interesting theo¬ 
retical inquiries have been raised, chiefly in regard to the man¬ 
ner in which the elementary atoms of which they are composed 
may be supposed to be grouped together. To a few of these 
I shall here briefly advert, as they will enable the reader better 
than anything else to form a proper estimate of the true state 
of our knowledge in this department of the science. 
Are vegetable principles binary compounds ? —1°. It has long 
been the opinion of certain chemists, and has lately been ably 
maintained by Dumas, that vegetable or animal principles con¬ 
taining three or more elements ought not to be regarded as 
simple combinations into which the elements enter singly, or 
as combinations of the first order, but as made up of two binary 
compounds of the first order, which unite together in virtue of 
their opposite electrical states, as an acid and an alkali do. 
Thus sugar may be considered as a compound of carbonic acid 
and carburetted hydrogen ; and the aethers as composed of 
aetlierine which gives the general character to all, and of water 
or an acid which imparts its peculiar properties to each. This 
view of organic principles is very simple, and gives a very clear 
idea of the way in which the elementary atoms are grouped ; 
but while we admit the probability of the hypothesis, so many 
facts militate against it that it cannot be received as a law. One 
of the strongest of these is, that we know only of one or two 
cases in which these compounds can be resolved into their 
supposed binary elements, and none in which they can be 
artificially produced by uniting them*. Many of the vegetable 
acids also appear so obviously to be oxides of a compound 
radical containing hydrogen and carbon, that we should be 
neglecting the most striking analogies were we to adopt the 
opinion of Dumas in regard to them; while, on the other hand, 
the discovery of benzule by Liebig and Wohler puts beyond 
question the existence of compound radicals of several ele¬ 
ments in which no such binary grouping can be supposed to 
have place. 
Dr. Prout's view. — 2°. A view of a different kind has been 
advanced by Dr. Prout in regard to the arrangement of the 
* The interesting observation of Brande, that in the galvanic circuit the 
vegetable alkalies are not decomposed, appears also to oppose the idea of their 
being binary compounds. 
2 i 
