A text-book of the science and art of bread-making : including the chemistry and analytic and practical testing of wheat, flour, and other materials employed in baking / by William Jago.

William Jago

Date:: 1895

Credit: A text-book of the science and art of bread-making : including the chemistry and analytic and practical testing of wheat, flour, and other materials employed in baking / by William Jago. Source: Wellcome Collection.

74/740 page 42

$4-J C IT AFTER IIL DESCRIPTION OF OROANIC COMPOUNDS. 82. “Organic” Chemical Compounds.—Cliemical science is coiunionly divided into two liraiiclies, Icnown respectively as “ Iiior<(anic” and “Orifanic” chemistry. Certain sulistances, whether they occur in nature, or ai'e jaepared in the laboratory, are obtained from mineral sources : the bodies descrilied in the preceding chajiter are instances of such compounds. There ai’e, on the other hand, l)odies which are obtained either from the animal or vegetable kingdom. Animals and vegetables are organi.sed bodies, that i.s, they have definite organs which adapt them foi- that series of processes which constitutes what is called “ life hence chemical compounds having a vegetable or animal origin are termed “organic.” Tho.se which are not thus obtained from organic sources are tei’ined “ inorgainc ” compounds : the two names have also been given to the branches of chemistry which treat respectively of these two classes of bodies, and of their properties and reactions. It was foi'inerly supposed tliat the .so-called oi’ganic bodies could only be obtained fi'om orgainc sources; but com])aratively i-ecent chemical in¬ vestigation has demonstrated that many such compounds tan be produced by artificial means from the elements of which they are composed, witliout the intervention of living organisms, and ('ven under such conditions as rendei- the existence of li\'ing organisms an impossi¬ bility. Alcohol and its deiTvations are e.xam])les. The definition of an oi'ganic body as om* produced as a r(*sult of “life” is evidently no longer tmiable, and chemi.sts have (mdeavoured, with more or less success, to frame new (hdinitions of organic chemistry. As all organic com¬ pounds contain carbon, it has been propos(‘d to define it as tlu' “chmnisfry of the carbon compounds;” again, as many oi’ganic liodies are well defined compound radic’ds, the jihrase, “chemistry of the conniound radicals ” has been jiroposed. 'riu'se definitions have not been found mitirely satisfactory, as tlnw are eitlu'r too wide or too narrow. I’or our present purpose. Organic Chemistry may be viewed, with sufficient accuracy, as that branch of the science which treats of the comioosition and properties of those com¬ pounds whoso usual source is either animal or vegetable. 83. Organised Structures.—Although organic compounds can$