<P> For historical reasons discussed below, a few types of carbon - containing compounds, such as carbides, carbonates, simple oxides of carbon (for example, CO and CO), and cyanides are considered inorganic . The distinction between organic and inorganic carbon compounds, while "useful in organizing the vast subject of chemistry is somewhat arbitrary". </P> <P> Organic chemistry is the science concerned with all aspects of organic compounds . Organic synthesis is the methodology of their preparation . </P> <P> For many centuries, Western physicians and chemists believed in vitalism . This was the widespread conception that substances found in organic nature are created from the chemical elements by the action of a "vital force" or "life - force" (vis vitalis) that only living organisms possess . Vitalism taught that these "organic" compounds were fundamentally different from the "inorganic" compounds that could be obtained from the elements by chemical manipulations . </P> <P> Vitalism survived for a while even after the rise of modern ideas about the atomic theory and chemical elements . It first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen . A more decisive experiment was Wöhler's 1828 synthesis of urea from the inorganic salts potassium cyanate and ammonium sulfate . Urea had long been considered an "organic" compound, as it was known to occur only in the urine of living organisms . Wöhler's experiments were followed by many others, in which increasingly complex "organic" substances were produced from "inorganic" ones without the involvement of any living organism . </P>

Why is it necessary to have hormones that are made up of different organic compounds