When he read a paper by Alfred Russel Wallace, "On the Law which has Regulated the Introduction of New Species", he saw similarities with Darwin's thoughts and urged him to publish to establish precedence.
Cando leu a publicación de Alfred Russel Wallace, "Sobre da lei que regula a introdución de novas especies", apreciou similitudes coas ideas de Darwin e fixo que se achegase a Darwin e motivalo a que publicase para establecer o seu precedente.