Seventeenth- and eighteenth-century commentators on the chemical composition of the brain.

The period between 1600 and 1800 was one of great change in the history of science, generally, and in the history of chemistry, specifically. It opened with Francis Bacon's visionary recognition of the benefits to mankind that would accrue from the expansion of scientia and closed with the overthrow of the phlogiston hypothesis. New chemical knowledge resulted from the efforts of the alchemists, especially in Paracelsians, and of the phlogistic philosophers, some of it recorded by writers of magic books (Thorndike, 1958; Camporesi, 1989). The authors of these works reflected 'the general mentality ... imbued with magic, occult beliefs, unreal suggestions, 'voices', and 'rumours', ... 'errors' and 'prejudices'. In respect to brain chemistry there appeared, beside the fantastic, elements of fact that characterise this period as embracing the 'pre-history' of neurochemistry.