During the year of my presidency of the Comparative Section of the Royal Society of Medicine, a continuous theme was selected for discussion, leading up, through the subjects which constituted the most rational means of appreciating its meaning and scope, to the culminating one, namely, that of Comparative Psychology and Animal Behaviour. Without such rational approach it would have been impossible, to my mind, for anyone not conversant with the immense and confusing literature that is now accumulating on the subject to grasp the transcending importance of animal behaviour study as a subject calling out for immediate exploitation, particularly by veterinary workers.