F. J. J.Buytendijk died on October 21st 1974 at the age of 87. His important contribution to the study of animal behaviour is analyzed here in relation to the historical development of animal psychology and ethology. The detailed study of his scientific production suggests, according to the authors, that some important findings, although largely not paid attention to in present-day literature, are akin to the conceptual and methodological evolution of comparative ethology.