[1] In 1885 he gave a course of lectures on Experimental Psychology at the Sorbonne, and in 1888 was appointed professor of that subject at the College of France.

His thesis for his doctors' degree, republished in 1882, Hérédité: étude psychologique (5th ed., 1889), was his most important and best known book.

[2] L'Hérédité psychologique is considered to have introduced Darwinian and Spencerian evolutionary ideas to France.

He paid particular attention to the physical element of mental life, ignoring all spiritual or nonmaterial factors in man.

In his work on La Psychologie anglaise contemporaine: l'école expérimentale (1870), he showed his sympathy with the sensationalist school, and again in his translation of Herbert Spencer's Principles of Psychology.