Paper, 'Experiments to prove the existence of a fluid in the nerves' by A S [Alexander Stuart ] Stuart shares the findings of experiments on animals in an attempt to prove the existence of a fluid in the nerves, also known as 'animal spirits'. Subject: Physiology / Neurology Published in Philosophical Transactions as 'Experiments to prove the existence of a fluid in the nerves' Read to the Royal Society on 22 June 1732 [1732]