The present work is a study on the relationships and contributions of medical thought, in the last quarter of the nineteenth century, regarding the institutionalization process of Social Sciences in Brazil. The object of this study may be established not only by its attempt of reasserting the role of a particular group of intellectuals who contributed to build a Brazilian social thought, but also and moreover as an undertaking of reflecting on the intellectual (and greatly political) work of Dr. Francisco Franco da Rocha, regarded as one of the most important names in the history of Brazilian psychiatry and alienism. Our inference concerns the existence of a peculiar social analysis, elaborated as psychiatric medicine evolved in Brazil, particularly the one drawn by such 'paulista' physician. In order to do so, we performed an investigation on Franco da Rocha's and other doctor's work and discussionswhich includes names from Nina Rodrigues, Arthur Ramos, Afrânio Peixoto to Manoel Bonfim. The referred work and discussions took place in a time of a historical and intellectual context full of medical prescriptions towards the establishment of a national identity. Ultimately, we concluded that there is a certain originality in the speech of Franco da Rocha who, by outlining his account on the social etiology of madness, makes use of a critical sense, shaping the social structure he sees-made evident by the multiplicity of his work. If on one side he did not rule out the theory of degeneration or eugenics, on the other, he did not resonate the most pessimist views on racial mixing and the presence of color people in the formation of national character, bridging between the alternative explanations of Brazil, already undertaken by other physicians.