All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young.

Zoological Philosophy: An Exposition with Regard to the Natural History of Animals (ed. Cambridge University Press, 2011) - ISBN: 9781108038423