ORGANIC SUBSTANCES. 663 
hope to arrive at a correct and unanimous opinion concerning the 
constitution of those bodies which occur in nature or which arise 
Srom the action of chemical agents upon them. 
These principles, although never positively denied, have also 
never been generally admitted. 
Historical Statement of the Views entertained upon Organic 
Composition. 
The first tolerably satisfactory experiments upon the compo- 
sition of organic substances were published in 1811 by Thénard 
and Gay-Lussac. The law of chemical proportions was then 
only partially developed, and had not attracted the attention of 
these chemists, who were consequently obliged to determine the 
relative quantities of the elements in hundredths of the analysed 
substance. The view to which these experiments led, namely, 
that those organic substances were neutral, in which, as in starch, 
sugar, wood, &c., the hydrogen and oxygen were in the same 
relative proportions as in water, whereas those containing oxygen 
in excess possessed the properties of acids, and that an excess of 
hydrogen, classed a substance amongst the resins, oils or spi- 
rituous fluids, although in accordance with the results of the 
analyses, has since been found to be incorrect. Some years after- 
wards, when I had endeavoured to establish the law of chemical 
proportions for inorganic substances, I undertook, with a similar 
object in view, the examination of organic composition. It then 
appeared that all organic bodies containing oxygen, including 
those not reckoned amongst the acids, could be made to com- 
bine with inorganic oxides in definite and often in multiple 
proportions, by which means, as in inorganic nature, the atomic 
weight, and with it a check upon the accuracy of the analytical 
results, could be obtained. At the same time it was observed 
that the oxygen of the organic substance was a multiple of the 
oxygen in the inorganic oxide with which it was combined, and 
that the amounts of the other constituents corresponded to a 
certain number of atoms, and could, as in inorganic compounds, 
be expressed by a formula. This similarity between organic 
substances containing oxygen and the inorganic oxides, led im- 
mediately to the idea that the organic bodies were oxides of 
compound radicals, whereas the inorganic were oxides of simple 
elements. 
This view I expressed in the second edition of my ‘ Manual 
