Gregorio Marañón, a pioneer in the practice and theory of endocrinology in Spain, also made his name in the period between wars as the writer of numerous essays and journalistic texts, as the leader of the Spanish movement for sexual reform and as "accoucheur" of the 1931 Republic. Marañón's fellow authors of the "generación del 14" - mainly a generation of essayists - attributed an explicit social and political function to science as a means for reforming and modernising Spanish society. In this dissertation is studied how science relates to social, political and moral elements in Marañon's essayistic and journalistic texts on the level of discourse. The focus is especially on the heterogeneity of subject positions, voices and discourses (amongst others, scientific and "ideological") in Marañón's texts (cf. Bakhtin's concepts of polyphony and heteroglossia). In a limited number of detailed text analyses is shown how the author in the course of the period examined gradually breaks away from his medical and scientific background and evolves towards an essayism on social and moral themes, and finally, develops a distinct interest in historical and cultural issues. While it is clear that in the later essays, a scientific perspective is adopted less frequently than in the earlier ones, (Spanish) science, and medicine in particular, turn into a privileged object of historical and ethical reflection in the 1933-1936 period. This thematic evolution is closely related to the social and political evolutions in Spain and contrasts with a constant in the author's discourse, which is the monologic tendency to fuse and to integrate heterogeneous or opposite elements in an all-embracing whole. In this way the apparent multiplicity of voices can mostly be reduced to the single voice of the author, while relations between discourses, rather then dialogic, or interacting dynamically, are dialectic, that is, striving for a synthesis. In Marañons essays, scientific (medical, biological) perspectives and discourses tend to coexist and fuse with social, moral and political ones.