Vitalist theory

The vitalist theory of Berzelius challenged by F. Wohler faged 28) who synthesized urea, (NH2)2CO. from NHaiOCN),... 

Little more than a decade later, the vitalistic theory suffered still further when Friedrich Wohler discovered in 1828 that it was possible to convert the "inorganic" salt ammonium cyanate into the "organic" substance urea, which had previously been found in human urine. 

Buchner and Rapp, 1898a). The same is true for Liebig s position, which was dominating at that time (Schunk, 1898). With Pasteur s work the vitalistic theory in turn gained the victory in the 1860 s (Buchner, 1898). 

By the mid-1800s, the weight of evidence was clearly against the vitalistic theory. As William Brande wrote in 1848 No definite line can be drawn between organic and inorganic chemistry. Any distinctions... must for the present be merely considered as matters of practical convenience calculated to further the progress of students. ... 

It is appropriate to start with the definition of isomerism. Different chemical substances (at least by some experimentally detmninable properties) are said to be isomers if and only if they have the same molecular formula. This definition restricts the notion of isomerism to compounds containing covalent bonds (for only then can one speak of molecules and molecular formulas), and possibly also other kinds of bcmds, such as ionic bonds. For example, urea and ammonium cyanate are isomers. Wohler s isomerization of the latter into the former substance (1828) is considered to represent the ezperimmtum cruci in disproving the vitalist theory. The above definition also impUes that two isomeric molecules consist of the same set of atoms bonded differently. 

The vitalists theory of fermentation (essentially dependent on living cells) by Pasteur... 

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