In the first edition of On the Origin of Species, Darwin briefly mentioned inheritance of acquired characters under the heading "Effects of Use and Disuse", expressing little doubt that use "strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited".
Na primeira edición de On the Origin of Species, Darwin mencionou brevemente a herdanza dos caracteres adquiridos baixo o título "Effects of Use and Disuse" (Efectos do uso e desuso), expresando poucas dúbidas de que o uso "reforza e agranda certas partes, e o desuso fainas diminuír; e que esas modificacións son herdadas".