William Isaac Thomas,
Sex and Society: Studies in the Social Psychology of Sex
“ This change of plan is carried out through the specialization of some organ, sense, or habit, to such a degree as to make practically a new type of the organism. In the human species, for example, the atrophied organs distributed through the body are evidence that the physical make-up of the species was well-nigh definitely fixed before the advantage of free hands led to an erect posture, thereby throwing certain sets of muscles out of use ”
