[Naturalism, novel and society in 19th-20th century transition in Spain.]

The second half of the nineteenth century in Spain was a period characterized by a strong presence of social science, which even came to permeate the masses. Evolutionary theories and some figures such as Charles Darwin himself were present in areas far from the scientific activity proper. The use of concepts and laws of biological origin for the diagnosis and political practice against certain problematic social realities, such as crime or poverty, gave rise to theories and intellectual schools that asserted the value of evolutionary principles for the analysis of complex realities of socio-cultural inequality. The attraction for difference and the scientific method, with the possibility of observation of poverty and social inequality that industrial development and modernity put forward to the writers, added to the naturalist and biological interest a literary curiosity for the degeneration, both physical and cultural, of that unfortunate part of humanity.