The development of a scientific understanding of synesthesia from early case studies (1849-1873)

The first case of synesthesia was reported in 1812 (Jewanski, Day, & Ward, 2009). However, it took almost seven decades before the idea of synesthesia entered the mainstream of science and, subsequently, art. There are no known new cases described between 1812 and 1848, but in the following three decades there are at least 11 reported cases of synesthesia and many reviews of these cases. This comes at an important period in the history of the neurosciences, and for sensory physiology in particular. However, the literature that describes synesthesia during this period is largely unknown to contemporary researchers and historians. The aim of this review is to discuss the reports of synesthesia during this period, providing translations of some key passages, and to place these reports within the contextual framework of nineteenth-century neuroscienc