The study of the transmissibility of cholera between man and the lower animals led to a study in comparative psychopathology during the course of the life of William Lauder Lindsay (1829-1880). The interrelationship of the physical and mental diseases of man with those of the lower animals led to his proposition for the understanding of a ‘Community of Disease’ of both body and mind. Through this formation of a ‘community’ Lauder Lindsay attempted to raise awareness amongst both veterinarians and physicians of the connections between their fields of expertise.

The historiography of Comparative Psychology to-date has focused on the development of the objective study of animal behaviours and rejection of the subjective premise that underlay the nineteenth century variants of the discipline. This paper presents a re-exploration of Comparative Psychology, with a focus on the animal-human relationship, providing an alternative conception of the role of animals within the science of the mind of the period. Lauder Lindsay’s Comparative Psychology explored the possibility of a shared moral insanity, the subject of his expertise as asylum physician in Perthshire. He used his patients within the asylum to understand the behaviour of animals, just as, if not to a greater extent, animals provided models for the understanding of the diseases of the human mind. The role of the animal within asylum medicine was not limited to the modelling and understanding of the mind - pets and farm animals all feature within the moral treatment regimen of the insane.

Lauder Lindsay’s community of disease, as a variant of comparative psychology, provides an important case study though which the many roles animals played within the early manifestations of psychology and the mental sciences can be explored. Through the treatment of animals as subjects, rather than objects of disease, a parallel historiography to that based on the nineteenth-century vivisected animal can be presented, expanding the place and role of animals within the scientific practice of this period. Although this paper will focus on the aspects of Lauder Lindsay’s work on the science of mind, his ‘Community of Disease’ gives an indication of the depth of work as yet not fully explored within the history of the ‘One Health’ movement.