'Danger in Familiarities' - the American Social Hygiene Association advises on 'The Correct Dancing Position' from 1922: 'Conventions are the fences society has built to protect you and the race. Familiarities arouse dangerous desires. They waste your power for the finest human companionship and love. Physical attraction alone will never wholly satisfy. Complete and lasting love is of the mind as well as the body' (click image to enlarge).