In the second half of the 19th century, linguists likened the history of languages to the evolution of species, a pattern also used as a model for the competition between literary genres. Those similes intensified the fear that science and its “monster” neologisms would eradicate the spirit and language of poetry. However, inspite of numerous texts stating that the words of science should and could not be put in verse, the rejection of the periphrasis used in Delille’s earlier scientific poetry shows that the critics and the poets of the time, just like the general public, did in fact consider many once specialized terms as proper terms, that one could hardly keep avoiding without being ridiculous. The essay hence analyzes the limits of a refusal of science that led to advocate a confinement of poetry, cutting it from its cultural environment, while deducting its models from life sciences.