Constituting the human via the animal in eighteenth-century experimental neurophysiology: Albrecht von Haller's sensibility trials.

This paper will address the use of animal models as a vital constituent of 'life science in the making' by focussing on the 'sensibility trials' conducted by the Swiss physiologist Albrecht von Haller (1708-1777). Haller was a pioneering figure in the early days of neurophysiological research, being not only influential for establishing animal experimentation as a viable method to gain knowledge about (human) neurological functions. He also tackled the question of sensibility as the most fundamental property of living bodies, which came to influence our conception of bodily feeling. In analysing some of his experiments on the nervous system, this paper addresses the following questions: what does sensibility or sensation signify in eighteenth-century physiology? How was it assessed or measured during experimentation? How were nervous functions 'read', i.e., how was the observable behaviour of an experimental animal interpreted? And finally: how did Haller address the differences between humans and animals in the context of his investigations?