The Birth of Biochemistry
Biological processes began to be investigated in chemical terms in the nineteenth century. By the beginning of the century, chemists had established that there was no fundamental chemical difference between matter of mineral and biological origin. The same elements (carbon, oxygen, hydrogen, etc) were found to be present in living and non-living bodies, and the disciplines of organic and inorganic chemistry were born. By the early 1830s the three key classes of foodstuffs, also recognised as the major constituents of all living organisms, had been identified as carbohydrates, fats, and “albuminous” matter (later renamed proteins).
Most nineteenth-century chemists believed that although they were built of the same elements, organic molecules were fundamentally different from inorganic compounds. It was thought that organic compounds were imbued with a 'vital force' that made life possible; that only living beings could create organic molecules; and that the creation processes were beyond human investigation and understanding. In contrast, the influential German chemist Justus von Liebig was certain that chemists would eventually produce organic compounds artificially. Hopkins took Liebig’s belief much further, showing that the ‘chemistry of life’ was accessible through experimental investigation.
A view on the progress and present state of animal chemistry by Jöns Jakob Berzelius
Like most chemists at the time, the Swedish chemist Jöns Jakob Berzelius (1779-1848) insisted on an inherently incomprehensible ‘vital power’ that fuelled life, anddid not obey the laws of chemistry and physics.
Baron Justus von Liebig (1803-1873)
The work of German organic chemist Liebig in applying chemistry to plant and animal physiology was especially influential. He discovered nitrogen was an essential plant nutrient, and invented the world’s first nitrogen based fertiliser. Liebig was an inspirational teacher and one of the first chemists to organize a laboratory as we know it today. The 'Liebig condenser' remains a basic tool of any organic chemistry laboratory.
Engraving of Liebig’s laboratory in Giessen Germany.
Liebig, aged 21 years, was appointed professor at Giessen where he established a major school of chemistry. He converted two large guardhouses of the city’s barracks into the world’s first research laboratory to which students flocked from many countries.
‘Animal chemistry; or, Organicchemistry in its application to physiology and pathology’ by Justus von Liebig
Liebig believed that chemical studies of animal and plant physiology and nutrition would have applications for human health. He put his new discoveries to use for the benefit of mankind.
‘Victuals consumed during November 1840 by a Company of the Body Guard of the Grand Duke of Hesse Darmstadt’ inLiebig’s ‘Researches on the Chemistry of Food' (1847).
This month-long study was both an investigation into the nature of an adequate diet to maintain health and a scientific study of the chemical oxidation of food. All faeces and urine were collected from the soldiers and analysed for carbon, hydrogen and oxygen.
Advertisement for Liebig's beef wine
Liebig promoted science as a means to social and political progress, and believed a nation’s health was of paramount importance. He devised an efficient method of producing beef extract from carcasses, founding his own Meat Extraction company marketing the extract as a cheap, nutritious alternative to real meat. It was also sold as a tonic – beef wine.
Oxo cube packaging
Liebig’s entrepreneurial legacy is the 'Oxo' beef bouillon cube, introduced in 1899 as a cheaper version of his meat extract.
Models of Ammonium cyanate and urea
In 1828 the German chemist Friedrich Wöhler (1800-1882) accidentally synthesized urea while trying to make ammonium cyanate from silver cyanate and ammonium chloride. This synthesis of organic from inorganic compounds disproved and undermined the 'vital force'theory. Liebig, alone among his contemporaries, accepted the significance of Wöhler’s work.