Epistemological considerations of philosophers and scientists from the late nineteenth century to the mid-twentieth century guided Brazilian physiologist Miguel Ozório de Almeida in formulating his researches and participating in national and international scientific debates. With his siblings, Álvaro Ozório de Almeida and Branca de Almeida Fialho, he participated in debates on Brazilian educational and scientific system’s reform and in international organizations. The family’s residence in Rio de Janeiro housed a laboratory that became a reference in experimental physiology researches in Brazil. (...) This article aims to present Miguel Ozório de Almeida’s conception of science, constructed mainly within the private laboratory’s sociability, providing new aspects of scientific work production in Brazil in the early twentieth century. I argue that Ozório de Almeida’s stand as an internationalist physiologist in national and international contexts was related to his reading of texts by Ernest Mach, Pierre Duhem, Henri Poincaré and William James. (shrink)