History of biochemistry
The history of biochemistry can be said to have started with the ancient Greeks who were interested in the composition and processes of life, although biochemistry as a specific scientific discipline has its beginning around the early 19th century. Some argued that the beginning of biochemistry may have been the discovery of the first enzyme, diastase (today called amylase), in 1833 by Anselme Payen, while others considered Eduard Buchner's first demonstration of a complex biochemical process alcoholic fermentation in cell-free extracts to be the birth of biochemistry. Some might also point to the influential work of Justus von Liebig from 1842, "Animal chemistry, or, Organic chemistry in its applications to physiology and pathology", which presented a chemical theory of metabolism, or even earlier to the 18th century studies on fermentation and respiration by Antoine Lavoisier.
Iatrochemistry
In 1609, Flemish chemist Jan Baptista van Helmont began a seven-year period of individual research, hoping to explore nature through chemistry, ultimately hoping to replace traditional learning. Van Helmont used chemical methods to study bodily products such as urine and blood. He studied the human body and its functions, and applied his knowledge of "chymistry" as a way of understanding and curing the body. Although he began as a follower of Paracelsus, van Helmont rejected many of his theories, most notably Galenic concept of the macrocosm with microcosm. In addition, van Helmont refused to accept the Paracelsian first principles (sulphur, salt, and mercury) as pre-existent in matter, believing instead that sulphur, salt and mercury were products of reactions that involved heat.