The first theory of eugenics was developed in 1869 by Francis Galton (1822–1911), who used the then-popular concept of "degeneration". He applied statistics to study human differences and the alleged "inheritance of intelligence", foreshadowing future uses of "intelligence testing" by the anthropometry school. Such theories were vividly described by the writer Émile Zola (1840–1902), who started publishing in 1871, a twenty-novel cycle, "Les Rougon-Macquart", where he linked heredity to behavior. Thus, Zola described the high-born Rougons as those involved in politics ("Son Excellence Eugène Rougon") and medicine ("Le Docteur Pascal") and the low-born Macquarts as those fatally falling into alcoholism ("L'Assommoir"), prostitution ("Nana"), and homicide ("La Bête humaine").