As an outcome of this alchemical doctrine the process of fermentation was supposed to have a purifying and elevating effect on the bodies which had been submitted to its influence.
The history of the alchemical period is treated in more detail in the article Alchemy, and of the iatrochemical in the article Medicine.
Have been some doubt as to the exact nature and import of the alchemical doctrines.
From the Alexandrians the science passed to the Arabs, who made discoveries and improved various methods of separating substances, and afterwards, from the 11th century, became seated in Europe, where the alchemical doctrines were assiduously studied until the 15th and 16th centuries.
From the mazy and incoherent alchemical and iatrochemical doctrines, the former based on false conceptions of matter, the latter on erroneous views of life processes and physiology, a new science arose - the study of the composition of substances.