Animal magnetism. Satirical artwork depicting a patient and animal magnetism practitioner with animal heads. Animal magnetism was developed by the German physician Franz Mesmer (1734-1815) in the 1770s. It involved manipulating a magnetic fluid thought to reside in living objects. The practice was later renamed 'mesmerism', and eventually led to the development of hypnosis. At lower left is a German copy of Ovid's 'Metamorphoses'. This 19th century artwork is from 'Die Karikatur und Satire in der Medizin' (Caricature and Satire in Medicine, 1921) by the German art historian and physician Eugen Hollander (1867-1932).