Sir David Ferrier FRS (13 January 1843 – 19 March 1928) was a pioneering Scottish neurologist and psychologist. Ferrier conducted experiments on the brains of animals such as monkeys and in 1881 became the first scientist to be prosecuted under the Cruelty to Animals Act, 1876 which had been enacted following a major public debate over vivisection. Life Ferrier was born in Woodside, Aberdeen, and educated at Aberdeen Grammar School before studying for an MA at Aberdeen University (graduated 1863). As a medical student, he began to work as a scientific assistant to the influential free-thinking philosopher and psychologist Alexander Bain (1818–1903), one of the founders of associative psychology. Around 1860, psychology was finding its scientific foundation mainly in Germany, with the rigorous research of Hermann von Helmholtz (1821–1894), who had trained as a physicist, and of Wilhelm Wundt (1832–1920). They focused their work mainly in the area of sensory psychophysiology, because it was the most rewarding for the approach based on the paradigms of experimental physics. Both worked at the University of Heidelberg. In 1864, Bain prompted Ferrier to spend some time in their laboratories. On returning to Scotland, Ferrier graduated in medicine in 1868 at the University of Edinburgh. A few years later, in 1870, he moved into London and started work as a neuropathologist at the King's College Hospital and at the National Hospital for Paralysis and Epilepsy, Queen Square. The latter – now the National Hospital for Neurology and Neurosurgery – was the first hospital in England to be dedicated to the treatment of neurological diseases and has a David Ferrier ward named in his memory. At that period, the great neurologist John Hughlings Jackson (1835–1911) worked in the same hospital as Ferrier. Jackson was refining his concepts of the sensorimotor functions of the nervous system, derived from clinical experience. Jackson proposed that there was an anatomical and physiological substrate for the localization of brain functions, which was hierarchically organized. Influenced by Jackson who became a close friend and mentor, Ferrier decided to embark on an experimental program. It aimed to extend the results of two German physiologists, Eduard Hitzig (1838–1907) and Gustav Fritsch (1837–1927). In 1870, they had published results on localized electrical stimulation of the motor cortex in dogs. Ferrier wanted also to test Jackson's idea that epilepsy had a cortical origin, as it was suggested by his clinical observations. Coincidentally, Ferrier had received